American Century Capital Value Fund Investor Class (ACTIX) N-CSRS Certified semi-annual shareholder report (management investment company)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number		811-00816
AMERICAN CENTURY MUTUAL FUNDS, INC.
(Exact name of registrant as specified in charter)
4500 MAIN STREET, KANSAS CITY, MISSOURI				64111
(Address of principal executive offices)				(Zip Code)
CHARLES A. ETHERINGTON 4500 MAIN STREET, KANSAS CITY, MISSOURI  64111
(Name and address of agent for service)
Registrant’s telephone number, including area code:			816-531-5575
Date of fiscal year end:	10-31
Date of reporting period:	04-30-2011

ITEM 1.  REPORTS TO STOCKHOLDERS.

SEMIANNUAL REPORT      |     APRIL 30, 2011

Balanced Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	23
Statement of Operations	24
Statement of Changes in Net Assets	25
Notes to Financial Statements	26
Financial Highlights	33
Additional Information	35

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12–18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	10 years	Since Inception	Inception Date
Investor Class	TWBIX	10.03%	12.66%	4.31%	4.37%	7.98%	10/20/88
Blended index(2)	—	9.62%	12.80%	4.69%	4.33%	9.00%(3)	—
S&P 500 Index	—	16.36%	17.22%	2.95%	2.82%	9.70%(3)	—
Barclays Capital U.S. Aggregate Bond Index	—	0.02%	5.36%	6.33%	5.74%	7.18%(3)	—
Institutional Class	ABINX	10.14%	12.80%	4.52%	4.58%	3.69%	5/1/00

(1) Total returns for periods less than one year are not annualized.

(2) The blended index combines two widely known indices in proportion to the asset mix of the fund. The S&P 500 Index represents 60% of the index and the remaining 40% is represented by the Barclays Capital U.S. Aggregate Bond Index.

(3) Since 10/31/88, the date nearest the Investor Class’s inception for which data are available.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class
0.91%	0.71%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. As interest rates rise, bond values will decline.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the indices are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the indices do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Stock Holdings	% of net assets
Exxon Mobil Corp.	2.3%
Chevron Corp.	1.5%
International Business Machines Corp.	1.4%
Microsoft Corp.	1.3%
General Electric Co.	1.3%
Johnson & Johnson	1.3%
Apple, Inc.	1.2%
AT&T, Inc.	1.1%
Philip Morris International, Inc.	1.1%
Wells Fargo & Co.	1.1%
Top Five Stock Industries	% of net assets
Oil, Gas & Consumable Fuels	7.1%
Pharmaceuticals	3.7%
Insurance	2.9%
IT Services	2.7%
Diversified Financial Services	2.3%
Types of Investments in Portfolio	% of net assets
Common Stocks	60.4%
U.S. Government Agency Mortgage-Backed Securities	10.5%
Corporate Bonds	10.4%
U.S. Treasury Securities	9.5%
U.S. Government Agency Securities and Equivalents	2.7%
Commercial Mortgage-Backed Securities	2.2%
Collateralized Mortgage Obligations	1.5%
Municipal Securities	1.1%
Sovereign Governments and Agencies	0.6%
Temporary Cash Investments	1.1%
Other Assets and Liabilities	—*
*Category is less than 0.05% of total net assets.
Key Fixed-Income Portfolio Statistics
Weighted Average Life	6.7 years
Average Duration (Effective)	5.1 years

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,100.30	$4.69	0.90%
Institutional Class	$1,000	$1,101.40	$3.65	0.70%
Hypothetical
Investor Class	$1,000	$1,020.33	$4.51	0.90%
Institutional Class	$1,000	$1,021.32	$3.51	0.70%

* Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares/ Principal Amount		Value
Common Stocks — 60.4%
AEROSPACE & DEFENSE — 1.0%
General Dynamics Corp.		40,039	$	2,915,640
Raytheon Co.		45,581		2,212,958
				5,128,598
AIR FREIGHT & LOGISTICS — 0.9%
United Parcel Service, Inc., Class B		62,742		4,703,768
AUTO COMPONENTS — 0.7%
Magna International, Inc.		25,889		1,326,811
TRW Automotive Holdings Corp.(1)		39,712		2,265,967
				3,592,778
AUTOMOBILES — 0.2%
Ford Motor Co.(1)		69,657		1,077,594
BEVERAGES — 1.0%
Coca-Cola Co. (The)		27,826		1,877,142
Coca-Cola Enterprises, Inc.		11,128		316,146
Constellation Brands, Inc., Class A(1)		11,879		265,971
Dr Pepper Snapple Group, Inc.		62,050		2,432,360
PepsiCo, Inc.		9,009		620,630
				5,512,249
BIOTECHNOLOGY — 1.2%
Amgen, Inc.(1)		35,769		2,033,468
Biogen Idec, Inc.(1)		32,184		3,133,112
Cephalon, Inc.(1)		18,160		1,394,688
				6,561,268
CAPITAL MARKETS — 1.3%
Franklin Resources, Inc.		8,350		1,078,152
Goldman Sachs Group, Inc. (The)		556		83,962
Legg Mason, Inc.		76,917		2,857,466
Morgan Stanley		114,906		3,004,792
				7,024,372
CHEMICALS — 0.9%
Monsanto Co.		14,374		978,007
PPG Industries, Inc.		27,958		2,646,784
W.R. Grace & Co.(1)		26,141		1,185,756
				4,810,547
COMMERCIAL BANKS — 1.5%
PNC Financial Services Group, Inc.		20,691		1,289,877
U.S. Bancorp.		37,225		961,149
Wells Fargo & Co.		201,664		5,870,439
				8,121,465
COMMUNICATIONS EQUIPMENT — 0.4%
Cisco Systems, Inc.		24,435		429,079
Harris Corp.		18,849		1,001,447
Motorola Solutions, Inc.(1)		8,110		372,087
Research In Motion Ltd.(1)		8,195		398,687
				2,201,300
COMPUTERS & PERIPHERALS — 2.1%
Apple, Inc.(1)		17,938		6,246,550
Dell, Inc.(1)		199,922		3,100,790
Hewlett-Packard Co.		6,070		245,046
Lexmark International, Inc., Class A(1)		58,749		1,894,655
				11,487,041
CONSTRUCTION & ENGINEERING — 0.4%
Chicago Bridge & Iron Co. NV New York Shares		1,805		73,175
KBR, Inc.		51,874		1,990,405
URS Corp.(1)		3,608		161,458
				2,225,038
CONSUMER FINANCE — 0.3%
American Express Co.		13,492		662,187
Cash America International, Inc.		25,011		1,186,772
				1,848,959
CONTAINERS & PACKAGING — 0.1%
Crown Holdings, Inc.(1)		8,520		318,648
DIVERSIFIED CONSUMER SERVICES — 0.4%
Career Education Corp.(1)		3,838		83,707
ITT Educational Services, Inc.(1)		28,175		2,020,993
				2,104,700
DIVERSIFIED FINANCIAL SERVICES — 2.3%
Bank of America Corp.		255,270		3,134,716
Citigroup, Inc.(1)		801,004		3,676,608
JPMorgan Chase & Co.		61,131		2,789,407
McGraw-Hill Cos., Inc. (The)		64,348		2,604,164
				12,204,895
DIVERSIFIED TELECOMMUNICATION SERVICES — 2.1%
AT&T, Inc.		197,394		6,142,901
Verizon Communications, Inc.		140,861		5,321,729
				11,464,630
ELECTRIC UTILITIES — 0.6%
Entergy Corp.		34,622		2,413,846
Exelon Corp.		17,362		731,808
				3,145,654

8

	Shares/ Principal Amount		Value
ELECTRICAL EQUIPMENT — 0.2%
Emerson Electric Co.	13,813	$	839,278
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 1.2%
Anixter International, Inc.	25		1,879
Corning, Inc.	78,816		1,650,407
TE Connectivity Ltd.	59,604		2,136,803
Vishay Intertechnology, Inc.(1)	134,279		2,562,043
			6,351,132
ENERGY EQUIPMENT & SERVICES — 1.0%
Core Laboratories NV	19,609		1,882,072
Diamond Offshore Drilling, Inc.	9,299		705,515
Schlumberger Ltd.	12,046		1,081,128
SEACOR Holdings, Inc.	15,884		1,569,816
			5,238,531
FOOD & STAPLES RETAILING — 0.7%
Walgreen Co.	74,142		3,167,346
Wal-Mart Stores, Inc.	12,387		681,038
			3,848,384
FOOD PRODUCTS — 1.7%
H.J. Heinz Co.	29,636		1,518,252
Hershey Co. (The)	42,825		2,471,431
Hormel Foods Corp.	7,036		206,929
Sara Lee Corp.	91,216		1,751,347
Smithfield Foods, Inc.(1)	4,976		117,235
Tyson Foods, Inc., Class A	142,609		2,837,919
			8,903,113
HEALTH CARE EQUIPMENT & SUPPLIES — 0.5%
Cooper Cos., Inc. (The)	2,320		173,768
Zimmer Holdings, Inc.(1)	38,488		2,511,342
			2,685,110
HEALTH CARE PROVIDERS & SERVICES — 1.9%
AMERIGROUP Corp.(1)	3,322		226,893
Cardinal Health, Inc.	34,534		1,508,790
Health Net, Inc.(1)	13,192		439,294
Humana, Inc.(1)	40,089		3,051,575
Magellan Health Services, Inc.(1)	13,208		687,080
UnitedHealth Group, Inc.	78,341		3,856,727
WellCare Health Plans, Inc.(1)	4,553		199,467
			9,969,826
HOTELS, RESTAURANTS & LEISURE — 0.1%
Brinker International, Inc.	12,925		311,363
McDonald’s Corp.	167		13,078
Starbucks Corp.	1,600		57,904
			382,345
HOUSEHOLD DURABLES — 0.1%
Tupperware Brands Corp.	8,708		554,438
HOUSEHOLD PRODUCTS — 0.6%
Colgate-Palmolive Co.	3,178		268,064
Procter & Gamble Co. (The)	42,880		2,782,912
			3,050,976
INDEPENDENT POWER PRODUCERS & ENERGY TRADERS — 0.2%
AES Corp. (The)(1)	87,684		1,160,936
INDUSTRIAL CONGLOMERATES — 1.8%
3M Co.	26,033		2,530,668
General Electric Co.	352,336		7,205,271
Seaboard Corp.	17		40,579
			9,776,518
INSURANCE — 2.9%
ACE Ltd.	24,299		1,634,108
Allied World Assurance Co. Holdings Ltd.	28,525		1,853,269
American Financial Group, Inc.	57,616		2,060,924
Berkshire Hathaway, Inc., Class B(1)	19,047		1,586,615
Chubb Corp. (The)	9,286		605,355
Horace Mann Educators Corp.	1,483		26,516
Principal Financial Group, Inc.	74,836		2,525,715
Prudential Financial, Inc.	56,356		3,574,098
Travelers Cos., Inc. (The)	22,915		1,450,061
			15,316,661
INTERNET & CATALOG RETAIL — 0.1%
Expedia, Inc.	13,894		347,767
INTERNET SOFTWARE & SERVICES — 0.7%
AOL, Inc.(1)	40,027		815,750
Google, Inc., Class A(1)	5,781		3,145,442
			3,961,192
IT SERVICES — 2.7%
Accenture plc, Class A	38,864		2,220,300
Computer Sciences Corp.	29,641		1,511,098
Global Payments, Inc.	11,185		595,490
International Business Machines Corp.	45,407		7,745,526
Visa, Inc., Class A	33,911		2,649,127
			14,721,541
LEISURE EQUIPMENT & PRODUCTS — 0.4%
Polaris Industries, Inc.	19,665		2,073,281
MACHINERY — 1.6%
Caterpillar, Inc.	37,043		4,275,133
Dover Corp.	29,014		1,974,113
Eaton Corp.	10,172		544,507
Parker-Hannifin Corp.	13,391		1,263,039
Sauer-Danfoss, Inc.(1)	11,121		656,250
			8,713,042

9

Shares/ Principal Amount Value

MEDIA — 2.0%
Comcast Corp., Class A		158,083	$	4,148,098
DirecTV, Class A(1)		39,487		1,918,673
Interpublic Group of Cos., Inc. (The)		103,754		1,219,110
Time Warner, Inc.		87,033		3,295,069
				10,580,950
METALS & MINING — 1.4%
Freeport-McMoRan Copper & Gold, Inc.		65,832		3,622,735
Newmont Mining Corp.		48,439		2,839,010
Walter Energy, Inc.		6,866		949,018
				7,410,763
MULTILINE RETAIL — 0.6%
Dillard’s, Inc., Class A		30,918		1,484,682
Target Corp.		38,846		1,907,339
				3,392,021
MULTI-UTILITIES — 0.6%
DTE Energy Co.		2,199		111,116
Integrys Energy Group, Inc.		56,454		2,955,931
				3,067,047
OIL, GAS & CONSUMABLE FUELS — 7.1%
Canadian Natural Resources Ltd.		13,082		614,331
Chevron Corp.		75,510		8,263,814
ConocoPhillips		68,831		5,432,831
Exxon Mobil Corp.		142,083		12,503,304
Murphy Oil Corp.		35,440		2,745,891
Occidental Petroleum Corp.		42,632		4,872,411
Sunoco, Inc.		19,524		832,894
Valero Energy Corp.		68,469		1,937,673
Williams Cos., Inc. (The)		20,338		674,611
				37,877,760
PAPER & FOREST PRODUCTS — 0.4%
Domtar Corp.		24,437		2,273,130
PERSONAL PRODUCTS — 0.6%
Estee Lauder Cos., Inc. (The), Class A		15,409		1,494,673
Herbalife Ltd.		18,906		1,697,381
				3,192,054
PHARMACEUTICALS — 3.7%
Abbott Laboratories		55,407		2,883,380
Bristol-Myers Squibb Co.		35,689		1,002,861
Eli Lilly & Co.		97,368		3,603,590
Forest Laboratories, Inc.(1)		70,134		2,325,643
Johnson & Johnson		109,369		7,187,731
Merck & Co., Inc.		22,286		801,182
Pfizer, Inc.		104,353		2,187,239
				19,991,626
REAL ESTATE INVESTMENT TRUSTS (REITs) — 0.4%
Rayonier, Inc.		29,042		1,927,227
Simon Property Group, Inc.		2,635		301,813
				2,229,040
ROAD & RAIL — 0.7%
CSX Corp.		39,150		3,080,713
Norfolk Southern Corp.		10,429		778,838
				3,859,551
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 2.1%
Intel Corp.		252,838		5,863,313
LSI Corp.(1)		283,809		2,080,320
Micron Technology, Inc.(1)		95,069		1,073,329
Teradyne, Inc.(1)		123,359		1,986,080
				11,003,042
SOFTWARE — 2.2%
Cadence Design Systems, Inc.(1)		39,835		413,487
Electronic Arts, Inc.(1)		13,767		277,818
Intuit, Inc.(1)		18,491		1,027,360
Microsoft Corp.		276,961		7,206,525
Oracle Corp.		53,453		1,926,981
Symantec Corp.(1)		42,203		829,289
				11,681,460
SPECIALTY RETAIL — 1.3%
AutoZone, Inc.(1)		8,984		2,536,902
Bed Bath & Beyond, Inc.(1)		29,056		1,630,623
Best Buy Co., Inc.		15,318		478,228
Williams-Sonoma, Inc.		50,382		2,187,082
				6,832,835
TEXTILES, APPAREL & LUXURY GOODS — 0.4%
VF Corp.		23,531		2,366,277
TOBACCO — 1.1%
Philip Morris International, Inc.		85,418		5,931,426
TOTAL COMMON STOCKS (Cost $254,162,416)				323,116,557
U.S. Government Agency Mortgage-Backed Securities(6) — 10.5%
FHLMC, 7.00%, 10/1/12(3)	$	20,524		21,256
FHLMC, 4.50%, 1/1/19(3)		986,791		1,051,182
FHLMC, 6.50%, 1/1/28(3)		70,175		79,268
FHLMC, 5.50%, 12/1/33(3)		619,258		670,330
FHLMC, 5.50%, 1/1/38(3)		1,493,938		1,611,078

10

Shares/ Principal Amount Value

FHLMC, 6.00%, 8/1/38(3)	$	409,077	$	448,583
FHLMC, 6.50%, 7/1/47(3)		67,335		75,334
FNMA, 7.50%, 11/1/11(3)		10,965		11,168
FNMA, 6.50%, 5/1/13(3)		1,447		1,591
FNMA, 6.50%, 5/1/13(3)		2,787		2,897
FNMA, 6.50%, 6/1/13(3)		439		483
FNMA, 6.50%, 6/1/13(3)		4,213		4,634
FNMA, 6.50%, 6/1/13(3)		6,055		6,660
FNMA, 6.50%, 6/1/13(3)		9,271		10,197
FNMA, 6.00%, 1/1/14(3)		28,754		31,369
FNMA, 6.00%, 4/1/14(3)		105,197		114,766
FNMA, 4.50%, 5/1/19(3)		1,154,178		1,228,049
FNMA, 5.00%, 9/1/20(3)		1,520,578		1,635,670
FNMA, 6.50%, 1/1/28(3)		24,816		28,077
FNMA, 7.00%, 1/1/28(3)		37,385		43,073
FNMA, 6.50%, 1/1/29(3)		86,109		97,425
FNMA, 7.50%, 7/1/29(3)		159,101		185,449
FNMA, 7.50%, 9/1/30(3)		46,594		54,288
FNMA, 6.50%, 9/1/31(3)		78,345		88,641
FNMA, 7.00%, 9/1/31(3)		24,690		28,485
FNMA, 6.50%, 1/1/32(3)		121,323		137,267
FNMA, 7.00%, 6/1/32(3)		310,955		358,172
FNMA, 6.50%, 8/1/32(3)		120,804		136,680
FNMA, 5.50%, 6/1/33(3)		643,956		697,770
FNMA, 5.50%, 7/1/33(3)		903,623		979,136
FNMA, 5.50%, 8/1/33(3)		973,432		1,054,779
FNMA, 5.50%, 9/1/33(3)		651,809		706,279
FNMA, 5.00%, 11/1/33(3)		2,742,606		2,915,556
FNMA, 5.50%, 1/1/34(3)		3,782,329		4,108,408
FNMA, 4.50%, 9/1/35(3)		2,358,117		2,445,111
FNMA, 5.00%, 2/1/36(3)		2,872,133		3,046,968
FNMA, 5.50%, 4/1/36(3)		1,156,206		1,251,020
FNMA, 5.50%, 5/1/36(3)		2,303,469		2,492,364
FNMA, 5.50%, 2/1/37(3)		740,095		798,936
FNMA, 6.00%, 7/1/37		5,079,629		5,581,297
FNMA, 6.50%, 8/1/37(3)		743,241		829,883
FNMA, 4.50%, 9/1/40		7,317,669		7,551,038
FNMA, 4.00%, 1/1/41		2,287,761		2,284,309
FNMA, 4.50%, 2/1/41		2,093,599		2,158,403
FNMA, 6.50%, 6/1/47(3)		57,924		64,550
FNMA, 6.50%, 8/1/47(3)		161,447		179,914
FNMA, 6.50%, 8/1/47(3)		234,426		261,241
FNMA, 6.50%, 9/1/47(3)		19,485		21,714
FNMA, 6.50%, 9/1/47(3)		68,642		76,494
FNMA, 6.50%, 9/1/47(3)		266,945		297,479
FNMA, 6.50%, 9/1/47(3)		327,483		364,942
GNMA, 7.00%, 4/20/26(3)		130,517		150,173
GNMA, 7.50%, 8/15/26(3)		70,741		82,322
GNMA, 7.00%, 2/15/28(3)		16,625		19,225
GNMA, 7.50%, 2/15/28(3)		35,281		41,144
GNMA, 7.00%, 12/15/28(3)		37,475		43,334
GNMA, 7.00%, 5/15/31(3)		143,985		166,760
GNMA, 5.50%, 11/15/32(3)		816,409		894,952
GNMA, 4.00%, 1/20/41		6,187,041		6,278,052
TOTAL U.S. GOVERNMENT AGENCY MORTGAGE-BACKED SECURITIES (Cost $52,761,609)				56,005,625
Corporate Bonds — 10.4%
AEROSPACE & DEFENSE — 0.1%
Lockheed Martin Corp., 4.25%, 11/15/19(3)		150,000		153,313
United Technologies Corp., 6.05%, 6/1/36(3)		454,000		513,514
				666,827
BEVERAGES — 0.1%
Anheuser-Busch InBev Worldwide, Inc., 7.75%, 1/15/19(3)		150,000		188,477
Anheuser-Busch InBev Worldwide, Inc., 6.875%, 11/15/19		250,000		302,014
Dr Pepper Snapple Group, Inc., 2.90%, 1/15/16(3)		60,000		60,379
PepsiCo, Inc., 4.875%, 11/1/40(3)		50,000		47,998
				598,868
BIOTECHNOLOGY(2)
Amgen, Inc., 3.45%, 10/1/20(3)		100,000		95,455
CAPITAL MARKETS — 1.1%
Bear Stearns Cos. LLC (The), 6.40%, 10/2/17(3)		330,000		377,608
Credit Suisse (New York), 5.00%, 5/15/13(3)		340,000		364,603
Credit Suisse (New York), 5.50%, 5/1/14(3)		200,000		221,470
Credit Suisse (New York), 6.00%, 2/15/18(3)		100,000		108,679
Credit Suisse (New York), 5.30%, 8/13/19(3)		230,000		246,928
Deutsche Bank AG (London), 4.875%, 5/20/13(3)		330,000		352,451
Deutsche Bank AG (London), 3.875%, 8/18/14(3)		190,000		200,131
Goldman Sachs Group, Inc. (The), 3.625%, 2/7/16(3)		525,000		529,683

11

Shares/ Principal Amount Value

Goldman Sachs Group, Inc. (The), 7.50%, 2/15/19(3)	$	900,000	$	1,071,005
Goldman Sachs Group, Inc. (The), 6.25%, 2/1/41(3)		100,000		103,083
Jefferies Group, Inc., 5.125%, 4/13/18		50,000		50,417
Jefferies Group, Inc., 8.50%, 7/15/19(3)		130,000		156,250
Korea Development Bank, 3.25%, 3/9/16(3)		130,000		128,673
Korea Development Bank, 4.00%, 9/9/16(3)		110,000		111,690
Morgan Stanley, 4.20%, 11/20/14(3)		200,000		208,553
Morgan Stanley, 6.625%, 4/1/18(3)		410,000		458,616
Morgan Stanley, 5.625%, 9/23/19(3)		250,000		260,457
Morgan Stanley, 5.50%, 7/24/20(3)		200,000		204,829
Morgan Stanley, 5.75%, 1/25/21(3)		250,000		260,719
UBS AG (Stamford Branch), 2.25%, 8/12/13(3)		100,000		101,703
UBS AG (Stamford Branch), 2.25%, 1/28/14(3)		80,000		81,052
UBS AG (Stamford Branch), 5.875%, 12/20/17(3)		380,000		425,014
				6,023,614
CHEMICALS — 0.2%
CF Industries, Inc., 6.875%, 5/1/18		210,000		237,563
Dow Chemical Co. (The), 5.90%, 2/15/15(3)		110,000		123,825
Dow Chemical Co. (The), 2.50%, 2/15/16(3)		170,000		166,981
Rohm & Haas Co., 5.60%, 3/15/13(3)		240,000		258,217
				786,586
COMMERCIAL BANKS — 0.7%
Barclays Bank plc, 5.00%, 9/22/16(3)		200,000		215,697
BB&T Corp., 5.70%, 4/30/14(3)		60,000		66,565
BB&T Corp., 3.20%, 3/15/16		190,000		191,851
BNP Paribas, 3.60%, 2/23/16(3)		130,000		132,391
BNP Paribas, 5.00%, 1/15/21(3)		80,000		80,803
Fifth Third Bancorp., 6.25%, 5/1/13(3)		170,000		184,781
HSBC Bank plc, 3.50%, 6/28/15(3)(4)		140,000		144,211
HSBC Holdings plc, 5.10%, 4/5/21		120,000		123,845
HSBC Holdings plc, 6.80%, 6/1/38(3)		80,000		86,089
Huntington Bancshares, Inc., 7.00%, 12/15/20(3)		30,000		33,676
Lloyds TSB Bank plc, 4.875%, 1/21/16(3)		130,000		136,631
National Australia Bank Ltd., 2.25%, 4/11/14(4)		320,000		322,405
National Australia Bank Ltd., 2.75%, 9/28/15(3)(4)		100,000		99,772
PNC Bank N.A., 6.00%, 12/7/17(3)		290,000		325,601
PNC Funding Corp., 4.25%, 9/21/15(3)		50,000		53,247
Royal Bank of Scotland plc (The), 3.95%, 9/21/15		220,000		224,385
SunTrust Bank, 7.25%, 3/15/18(3)		110,000		127,593
SunTrust Banks, Inc., 3.60%, 4/15/16(3)		50,000		50,713
U.S. Bancorp., 3.44%, 2/1/16		120,000		121,291
Wachovia Bank N.A., 4.80%, 11/1/14(3)		373,000		402,706
Wachovia Bank N.A., 4.875%, 2/1/15(3)		123,000		132,908
Wells Fargo & Co., 3.68%, 6/15/16(3)		140,000		144,113
Wells Fargo & Co., 5.625%, 12/11/17(3)		50,000		55,884
Wells Fargo & Co., 4.60%, 4/1/21(3)		190,000		192,564
				3,649,722
COMMERCIAL SERVICES & SUPPLIES — 0.2%
Corrections Corp. of America, 6.25%, 3/15/13(3)		250,000		250,625
Corrections Corp. of America, 7.75%, 6/1/17(3)		90,000		99,000
Republic Services, Inc., 5.50%, 9/15/19(3)		300,000		326,963
Waste Management, Inc., 6.125%, 11/30/39(3)		120,000		127,940
				804,528
COMMUNICATIONS EQUIPMENT(2)
Cisco Systems, Inc., 5.90%, 2/15/39(3)		130,000		139,187
CONSUMER FINANCE — 0.3%
American Express Centurion Bank, 5.55%, 10/17/12(3)		150,000		159,167
American Express Centurion Bank, 6.00%, 9/13/17(3)		250,000		284,606

12

Shares/ Principal Amount Value

American Express Co., 7.25%, 5/20/14(3)	$	200,000	$	229,720
American Honda Finance Corp., 2.375%, 3/18/13(3)(4)		170,000		173,110
American Honda Finance Corp., 2.50%, 9/21/15(3)(4)		220,000		218,941
Capital One Bank USA N.A., 8.80%, 7/15/19(3)		250,000		320,863
Nissan Motor Acceptance Corp., 3.25%, 1/30/13(3)(4)		50,000		51,202
SLM Corp., 5.00%, 10/1/13(3)		180,000		187,753
SLM Corp., 6.25%, 1/25/16(3)		130,000		138,014
				1,763,376
CONTAINERS & PACKAGING — 0.1%
Ball Corp., 7.125%, 9/1/16(3)		130,000		142,350
Ball Corp., 6.75%, 9/15/20(3)		120,000		126,900
				269,250
DIVERSIFIED FINANCIAL SERVICES — 1.3%
Arch Western Finance LLC, 6.75%, 7/1/13(3)		47,000		47,529
Bank of America Corp., 4.50%, 4/1/15(3)		190,000		200,135
Bank of America Corp., 6.50%, 8/1/16(3)		620,000		700,027
Bank of America Corp., 5.75%, 12/1/17(3)		150,000		162,117
Bank of America N.A., 5.30%, 3/15/17(3)		720,000		757,108
Citigroup, Inc., 6.00%, 12/13/13(3)		330,000		361,343
Citigroup, Inc., 6.01%, 1/15/15(3)		520,000		576,960
Citigroup, Inc., 4.75%, 5/19/15		70,000		74,660
Citigroup, Inc., 6.125%, 5/15/18(3)		660,000		730,262
Citigroup, Inc., 8.50%, 5/22/19(3)		100,000		124,864
General Electric Capital Corp., 3.75%, 11/14/14(3)		200,000		210,747
General Electric Capital Corp., 2.25%, 11/9/15(3)		200,000		196,345
General Electric Capital Corp., 5.625%, 9/15/17(3)		450,000		498,898
General Electric Capital Corp., 6.00%, 8/7/19(3)		350,000		390,620
General Electric Capital Corp., 4.375%, 9/16/20(3)		320,000		316,463
General Electric Capital Corp., 4.625%, 1/7/21(3)		160,000		161,261
General Electric Capital Corp., 5.30%, 2/11/21(3)		80,000		83,232
JPMorgan Chase & Co., 3.70%, 1/20/15(3)		110,000		114,333
JPMorgan Chase & Co., 3.45%, 3/1/16		190,000		192,497
JPMorgan Chase & Co., 6.00%, 1/15/18(3)		840,000		936,599
				6,836,000
DIVERSIFIED TELECOMMUNICATION SERVICES — 0.7%
Alltel Corp., 7.875%, 7/1/32(3)		100,000		131,267
AT&T, Inc., 6.80%, 5/15/36(3)		350,000		389,397
AT&T, Inc., 6.55%, 2/15/39(3)		470,000		514,783
British Telecommunications plc, 5.95%, 1/15/18(3)		120,000		133,450
Cellco Partnership/Verizon Wireless Capital LLC, 8.50%, 11/15/18(3)		330,000		429,156
CenturyLink, Inc., 6.15%, 9/15/19(3)		140,000		147,337
CenturyLink, Inc., 7.60%, 9/15/39(3)		60,000		60,827
Deutsche Telekom International Finance BV, 6.75%, 8/20/18(3)		150,000		178,338
Embarq Corp., 7.08%, 6/1/16(3)		69,000		78,153
Qwest Corp., 7.875%, 9/1/11(3)		120,000		123,000
Qwest Corp., 7.50%, 10/1/14(3)		200,000		227,500
Telecom Italia Capital SA, 6.175%, 6/18/14(3)		340,000		371,136
Telecom Italia Capital SA, 7.00%, 6/4/18(3)		130,000		145,145
Telecom Italia Capital SA, 7.175%, 6/18/19(3)		80,000		90,392
Telefonica Emisiones SAU, 5.88%, 7/15/19(3)		220,000		235,683
Telefonica Emisiones SAU, 5.46%, 2/16/21		160,000		166,493
Verizon Communications, Inc., 7.35%, 4/1/39(3)		160,000		192,529
Windstream Corp., 7.875%, 11/1/17(3)		150,000		162,750
				3,777,336
ELECTRIC UTILITIES — 0.2%
Carolina Power & Light Co., 5.15%, 4/1/15(3)		100,000		110,968
Cleveland Electric Illuminating Co. (The), 5.70%, 4/1/17(3)		81,000		87,494
Duke Energy Corp., 6.30%, 2/1/14(3)		100,000		111,911

13

Shares/ Principal Amount Value

Duke Energy Corp., 3.95%, 9/15/14(3)	$	130,000	$	137,660
Edison International, 3.75%, 9/15/17(3)		130,000		129,959
FirstEnergy Solutions Corp., 6.05%, 8/15/21(3)		300,000		320,253
Florida Power Corp., 6.35%, 9/15/37(3)		230,000		262,962
Southern California Edison Co., 5.625%, 2/1/36(3)		60,000		63,254
				1,224,461
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS(2)
Jabil Circuit, Inc., 7.75%, 7/15/16(3)		150,000		171,000
Jabil Circuit, Inc., 5.625%, 12/15/20(3)		80,000		80,400
				251,400
ENERGY EQUIPMENT & SERVICES — 0.1%
Ensco plc, 3.25%, 3/15/16(3)		120,000		121,319
Transocean, Inc., 6.50%, 11/15/20(3)		100,000		112,528
Weatherford International Ltd., 9.625%, 3/1/19(3)		150,000		194,928
				428,775
FOOD & STAPLES RETAILING — 0.3%
CVS Caremark Corp., 6.60%, 3/15/19(3)		350,000		406,985
Kroger Co. (The), 6.40%, 8/15/17(3)		200,000		233,502
Wal-Mart Stores, Inc., 5.875%, 4/5/27(3)		468,000		521,528
Wal-Mart Stores, Inc., 6.20%, 4/15/38(3)		220,000		244,327
Wal-Mart Stores, Inc., 5.00%, 10/25/40(3)		150,000		142,361
				1,548,703
FOOD PRODUCTS — 0.2%
Archer Daniels Midland Co., 5.765%, 3/1/41(3)		130,000		138,705
Kellogg Co., 4.45%, 5/30/16(3)		200,000		217,195
Kraft Foods, Inc., 6.00%, 2/11/13(3)		70,000		75,823
Kraft Foods, Inc., 6.125%, 2/1/18(3)		160,000		181,965
Kraft Foods, Inc., 5.375%, 2/10/20(3)		330,000		358,044
Mead Johnson Nutrition Co., 3.50%, 11/1/14(3)		120,000		125,879
				1,097,611
GAS UTILITIES — 0.1%
CenterPoint Energy Resources Corp., 6.25%, 2/1/37(3)		330,000		341,548
HEALTH CARE EQUIPMENT & SUPPLIES — 0.1%
Baxter International, Inc., 5.90%, 9/1/16(3)		130,000		151,722
Covidien International Finance SA, 1.875%, 6/15/13(3)		170,000		172,859
				324,581
HEALTH CARE PROVIDERS & SERVICES — 0.2%
Express Scripts, Inc., 5.25%, 6/15/12(3)		230,000		240,817
Express Scripts, Inc., 7.25%, 6/15/19(3)		360,000		435,781
Medco Health Solutions, Inc., 7.25%, 8/15/13(3)		270,000		302,932
WellPoint, Inc., 5.80%, 8/15/40(3)		60,000		60,972
				1,040,502
HOTELS, RESTAURANTS & LEISURE — 0.1%
McDonald’s Corp., 5.35%, 3/1/18(3)		170,000		191,387
Wyndham Worldwide Corp., 6.00%, 12/1/16(3)		50,000		53,607
Yum! Brands, Inc., 5.30%, 9/15/19(3)		310,000		332,807
				577,801
HOUSEHOLD DURABLES — 0.1%
Jarden Corp., 8.00%, 5/1/16		230,000	��	253,575
Toll Brothers Finance Corp., 6.75%, 11/1/19(3)		100,000		104,291
				357,866
INDEPENDENT POWER PRODUCERS & ENERGY TRADERS(2)
Exelon Generation Co. LLC, 5.20%, 10/1/19(3)		150,000		156,604
INDUSTRIAL CONGLOMERATES — 0.1%
General Electric Co., 5.00%, 2/1/13(3)		158,000		168,749
General Electric Co., 5.25%, 12/6/17(3)		230,000		255,160
				423,909
INSURANCE — 0.5%
Allstate Corp. (The), 7.45%, 5/16/19		150,000		181,083
American International Group, Inc., 3.65%, 1/15/14		70,000		71,846
American International Group, Inc., 5.85%, 1/16/18(3)		250,000		265,044
American International Group, Inc., 8.25%, 8/15/18(3)		100,000		119,093

14

Shares/ Principal Amount Value

Berkshire Hathaway Finance Corp., 4.25%, 1/15/21(3)	$	120,000	$	121,936
CNA Financial Corp., 5.875%, 8/15/20(3)		60,000		63,600
CNA Financial Corp., 5.75%, 8/15/21		50,000		52,568
Genworth Financial, Inc., 7.20%, 2/15/21(3)		70,000		70,412
Hartford Financial Services Group, Inc., 4.00%, 3/30/15(3)		180,000		185,248
Hartford Financial Services Group, Inc., 6.30%, 3/15/18(3)		110,000		121,013
Lincoln National Corp., 6.25%, 2/15/20(3)		160,000		180,125
MetLife Global Funding I, 5.125%, 4/10/13(3)(4)		200,000		214,247
MetLife, Inc., 6.75%, 6/1/16(3)		260,000		304,839
New York Life Global Funding, 4.65%, 5/9/13(3)(4)		150,000		160,709
Prudential Financial, Inc., 7.375%, 6/15/19(3)		100,000		119,345
Prudential Financial, Inc., 5.375%, 6/21/20(3)		70,000		74,520
Prudential Financial, Inc., 5.40%, 6/13/35(3)		270,000		257,907
				2,563,535
INTERNET SOFTWARE & SERVICES(2)
eBay, Inc., 3.25%, 10/15/20(3)		60,000		55,787
MACHINERY(2)
Deere & Co., 5.375%, 10/16/29(3)		200,000		215,114
MEDIA — 0.8%
CBS Corp., 4.30%, 2/15/21(3)		160,000		154,227
Comcast Corp., 5.90%, 3/15/16(3)		339,000		382,434
Comcast Corp., 5.70%, 5/15/18(3)		120,000		132,990
Comcast Corp., 6.40%, 5/15/38(3)		220,000		234,425
Comcast Corp., 6.40%, 3/1/40(3)		80,000		85,375
DirecTV Holdings LLC/DirecTV Financing Co., Inc., 4.75%, 10/1/14(3)		155,000		168,253
DirecTV Holdings LLC/DirecTV Financing Co., Inc., 3.55%, 3/15/15(3)		190,000		196,910
DirecTV Holdings LLC/DirecTV Financing Co., Inc., 5.00%, 3/1/21(3)		380,000		390,883
Interpublic Group of Cos., Inc. (The), 10.00%, 7/15/17(3)		300,000		359,250
Lamar Media Corp., 9.75%, 4/1/14(3)		150,000		175,500
NBCUniversal Media LLC, 5.15%, 4/30/20(3)(4)		90,000		94,252
NBCUniversal Media LLC, 4.375%, 4/1/21(4)		220,000		215,317
NBCUniversal Media LLC, 5.95%, 4/1/41(4)		70,000		70,435
News America, Inc., 6.90%, 8/15/39(3)		150,000		169,033
Omnicom Group, Inc., 4.45%, 8/15/20(3)		145,000		143,741
Time Warner Cable, Inc., 5.40%, 7/2/12(3)		350,000		368,407
Time Warner Cable, Inc., 6.75%, 7/1/18(3)		270,000		311,572
Time Warner, Inc., 3.15%, 7/15/15(3)		140,000		143,573
Time Warner, Inc., 7.70%, 5/1/32(3)		200,000		242,161
Virgin Media Secured Finance plc, 6.50%, 1/15/18(3)		250,000		275,000
Virgin Media Secured Finance plc, 5.25%, 1/15/21(3)(4)		100,000		102,568
				4,416,306
METALS & MINING — 0.3%
Anglo American Capital plc, 4.45%, 9/27/20(3)(4)		130,000		132,265
AngloGold Ashanti Holdings plc, 5.375%, 4/15/20(3)		180,000		185,563
ArcelorMittal, 9.85%, 6/1/19(3)		240,000		309,811
ArcelorMittal, 5.25%, 8/5/20(3)		120,000		120,926
ArcelorMittal, 5.50%, 3/1/21(3)		140,000		142,294
Freeport-McMoRan Copper & Gold, Inc., 8.375%, 4/1/17(3)		210,000		231,797
Newmont Mining Corp., 6.25%, 10/1/39(3)		120,000		129,979
Rio Tinto Finance USA Ltd., 3.50%, 11/2/20(3)		80,000		76,664
Teck Resources Ltd., 5.375%, 10/1/15(3)		70,000		76,952
Vale Overseas Ltd., 5.625%, 9/15/19(3)		210,000		224,672
Vale Overseas Ltd., 4.625%, 9/15/20		150,000		149,248
				1,780,171
MULTILINE RETAIL(2)
Macy’s Retail Holdings, Inc., 5.35%, 3/15/12(3)		175,000		181,125

15

Shares/ Principal Amount Value

MULTI-UTILITIES — 0.2%
CMS Energy Corp., 4.25%, 9/30/15	$	160,000	$	164,473
CMS Energy Corp., 8.75%, 6/15/19(3)		180,000		220,237
Dominion Resources, Inc., 6.40%, 6/15/18(3)		260,000		301,551
Pacific Gas & Electric Co., 5.80%, 3/1/37(3)		133,000		137,876
PG&E Corp., 5.75%, 4/1/14(3)		60,000		66,048
Sempra Energy, 8.90%, 11/15/13(3)		170,000		197,893
Sempra Energy, 6.50%, 6/1/16(3)		100,000		115,317
				1,203,395
OFFICE ELECTRONICS — 0.1%
Xerox Corp., 5.65%, 5/15/13(3)		80,000		86,535
Xerox Corp., 4.25%, 2/15/15(3)		200,000		212,359
				298,894
OIL, GAS & CONSUMABLE FUELS — 1.1%
Anadarko Petroleum Corp., 5.95%, 9/15/16(3)		50,000		55,940
Anadarko Petroleum Corp., 6.45%, 9/15/36(3)		250,000		258,729
Apache Corp., 5.25%, 2/1/42(3)		60,000		58,778
BP Capital Markets plc, 3.20%, 3/11/16(3)		120,000		121,164
BP Capital Markets plc, 4.50%, 10/1/20(3)		100,000		101,052
Cenovus Energy, Inc., 4.50%, 9/15/14(3)		140,000		151,733
Chesapeake Energy Corp., 7.625%, 7/15/13(3)		100,000		110,250
ConocoPhillips, 5.75%, 2/1/19(3)		240,000		275,766
El Paso Corp., 7.25%, 6/1/18(3)		200,000		226,412
Enbridge Energy Partners LP, 6.50%, 4/15/18(3)		130,000		149,090
Enbridge Energy Partners LP, 5.20%, 3/15/20(3)		100,000		106,320
Enbridge Energy Partners LP, 5.50%, 9/15/40(3)		120,000		116,906
Enterprise Products Operating LLC, 3.70%, 6/1/15(3)		150,000		156,014
Enterprise Products Operating LLC, 6.30%, 9/15/17(3)		390,000		447,458
Enterprise Products Operating LLC, 5.20%, 9/1/20(3)		100,000		105,706
Enterprise Products Operating LLC, 5.95%, 2/1/41(3)		125,000		125,940
EOG Resources, Inc., 5.625%, 6/1/19(3)		150,000		168,180
Hess Corp., 6.00%, 1/15/40(3)		110,000		114,864
Kinder Morgan Energy Partners LP, 6.85%, 2/15/20(3)		200,000		233,526
Kinder Morgan Energy Partners LP, 6.50%, 9/1/39(3)		130,000		138,696
Magellan Midstream Partners LP, 6.55%, 7/15/19(3)		150,000		173,827
Marathon Petroleum Corp., 3.50%, 3/1/16(3)(4)		50,000		50,741
Marathon Petroleum Corp., 6.50%, 3/1/41(3)(4)		60,000		63,309
Newfield Exploration Co., 6.875%, 2/1/20(3)		200,000		212,500
Noble Energy, Inc., 6.00%, 3/1/41(3)		60,000		62,376
Peabody Energy Corp., 6.50%, 9/15/20(3)		70,000		75,338
Pemex Project Funding Master Trust, 6.625%, 6/15/35(3)		50,000		51,087
Petrobras International Finance Co. - Pifco, 5.75%, 1/20/20(3)		120,000		125,353
Petrobras International Finance Co. - Pifco, 5.375%, 1/27/21		240,000		244,758
Petroleos Mexicanos, 6.00%, 3/5/20(3)		120,000		128,940
Plains All American Pipeline LP/PAA Finance Corp., 3.95%, 9/15/15(3)		60,000		62,526
Plains All American Pipeline LP/PAA Finance Corp., 8.75%, 5/1/19(3)		190,000		240,848
Shell International Finance BV, 3.10%, 6/28/15(3)		140,000		145,392
Shell International Finance BV, 6.375%, 12/15/38(3)		50,000		58,304
Suncor Energy, Inc., 6.10%, 6/1/18(3)		174,000		198,815
Talisman Energy, Inc., 7.75%, 6/1/19(3)		350,000		433,165
TransCanada PipeLines Ltd., 3.80%, 10/1/20		80,000		78,366
Williams Partners LP, 5.25%, 3/15/20(3)		120,000		127,930
Williams Partners LP, 4.125%, 11/15/20(3)		80,000		78,040
				5,834,139

16

Shares/ Principal Amount Value

PAPER & FOREST PRODUCTS — 0.1%
Georgia-Pacific LLC, 5.40%, 11/1/20(3)(4)	$	270,000	$	273,096
International Paper Co., 9.375%, 5/15/19(3)		110,000		143,679
				416,775
PHARMACEUTICALS — 0.3%
Abbott Laboratories, 5.30%, 5/27/40(3)		100,000		100,961
AstraZeneca plc, 5.40%, 9/15/12(3)		295,000		314,170
AstraZeneca plc, 5.90%, 9/15/17(3)		200,000		231,796
Pfizer, Inc., 7.20%, 3/15/39(3)		170,000		215,708
Sanofi-Aventis SA, 4.00%, 3/29/21(3)		95,000		94,820
Watson Pharmaceuticals, Inc., 5.00%, 8/15/14(3)		410,000		444,565
				1,402,020
REAL ESTATE INVESTMENT TRUSTS (REITs) — 0.3%
AMB Property LP, 6.625%, 12/1/19(3)		160,000		178,341
Developers Diversified Realty Corp., 5.375%, 10/15/12(3)		70,000		72,643
Developers Diversified Realty Corp., 4.75%, 4/15/18(3)		230,000		227,984
Digital Realty Trust LP, 5.875%, 2/1/20(3)		75,000		79,501
HCP, Inc., 3.75%, 2/1/16(3)		160,000		163,302
HCP, Inc., 5.375%, 2/1/21		215,000		224,076
Host Hotels & Resorts LP, 6.00%, 11/1/20(3)		20,000		19,950
Kimco Realty Corp., 6.875%, 10/1/19(3)		90,000		104,671
Simon Property Group LP, 5.75%, 12/1/15(3)		140,000		156,881
Ventas Realty LP/Ventas Capital Corp., 3.125%, 11/30/15(3)		195,000		193,192
				1,420,541
ROAD & RAIL(2)
Burlington Northern Santa Fe LLC, 5.05%, 3/1/41(3)		60,000		56,268
SOFTWARE — 0.1%
Intuit, Inc., 5.75%, 3/15/17(3)		254,000		283,069
Oracle Corp., 5.375%, 7/15/40(3)(4)		445,000		446,925
				729,994
SPECIALTY RETAIL — 0.1%
Gap, Inc. (The), 5.95%, 4/12/21(3)		110,000		111,519
Home Depot, Inc. (The), 5.40%, 3/1/16(3)		170,000		190,260
Home Depot, Inc. (The), 5.95%, 4/1/41(3)		100,000		103,052
Staples, Inc., 9.75%, 1/15/14(3)		145,000		174,496
				579,327
TEXTILES, APPAREL & LUXURY GOODS(2)
Hanesbrands, Inc., 6.375%, 12/15/20(3)		140,000		139,300
TOBACCO(2)
Altria Group, Inc., 10.20%, 2/6/39(3)		50,000		73,499
WIRELESS TELECOMMUNICATION SERVICES — 0.2%
America Movil SAB de CV, 5.00%, 10/16/19(3)		200,000		209,559
America Movil SAB de CV, 5.00%, 3/30/20(3)		110,000		115,382
American Tower Corp., 4.625%, 4/1/15(3)		230,000		242,584
Rogers Communications, Inc., 6.25%, 6/15/13(3)		180,000		198,803
SBA Telecommunications, Inc., 8.25%, 8/15/19(3)		120,000		133,050
Vodafone Group plc, 5.625%, 2/27/17(3)		210,000		236,159
				1,135,537
TOTAL CORPORATE BONDS (Cost $52,538,598)				55,686,237
U.S. Treasury Securities — 9.5%
U.S. Treasury Bonds, 5.50%, 8/15/28(3)		70,000		82,480
U.S. Treasury Bonds, 5.25%, 2/15/29(3)		1,239,000		1,420,011
U.S. Treasury Bonds, 5.375%, 2/15/31(3)		2,680,000		3,119,689
U.S. Treasury Bonds, 4.375%, 11/15/39(3)		2,970,000		2,960,255
U.S. Treasury Notes, 1.375%, 9/15/12(3)		4,200,000		4,259,556
U.S. Treasury Notes, 1.375%, 10/15/12(3)		4,500,000		4,565,214
U.S. Treasury Notes, 0.50%, 11/30/12(3)		2,960,000		2,963,700
U.S. Treasury Notes, 1.375%, 1/15/13(3)		1,500,000		1,522,911
U.S. Treasury Notes, 1.375%, 5/15/13(3)		1,000,000		1,015,317

17

Shares/ Principal Amount Value

U.S. Treasury Notes, 1.25%, 3/15/14(3)	$	6,120,000	$	6,170,227
U.S. Treasury Notes, 2.375%, 8/31/14(3)		2,500,000		2,597,070
U.S. Treasury Notes, 2.125%, 12/31/15(3)		8,150,000		8,260,155
U.S. Treasury Notes, 2.00%, 4/30/16(3)(5)		5,000,000		5,008,180
U.S. Treasury Notes, 2.625%, 4/30/18(3)(5)		375,000		374,121
U.S. Treasury Notes, 2.625%, 8/15/20(3)		1,871,000		1,780,520
U.S. Treasury Notes, 2.625%, 11/15/20(3)		4,000,000		3,787,812
U.S. Treasury Notes, 3.625%, 2/15/21		1,000,000		1,028,125
TOTAL U.S. TREASURY SECURITIES (Cost $50,427,692)				50,915,343
U.S. Government Agency Securities and Equivalents — 2.7%
FIXED-RATE U.S. GOVERNMENT AGENCY SECURITIES — 2.0%
FHLMC, 2.875%, 2/9/15(3)		2,900,000		3,038,762
FNMA, 2.75%, 3/13/14(3)		4,000,000		4,189,456
FNMA, 5.00%, 2/13/17(3)		2,200,000		2,499,627
FNMA, 6.625%, 11/15/30(3)		761,000		971,098
				10,698,943
GOVERNMENT-BACKED CORPORATE BONDS(7) — 0.7%
Ally Financial, Inc., 1.75%, 10/30/12(3)		2,000,000		2,039,820
Citigroup Funding, Inc., 1.875%, 11/15/12(3)		1,800,000		1,838,388
				3,878,208
TOTAL U.S. GOVERNMENT AGENCY SECURITIES AND EQUIVALENTS (Cost $13,914,172)				14,577,151
Commercial Mortgage-Backed Securities(6) — 2.2%
Banc of America Commercial Mortgage, Inc., Series 2004-1, Class A4 SEQ, 4.76%, 11/10/39(3)		400,000		425,458
Banc of America Commercial Mortgage, Inc., Series 2004-6, Class A3 SEQ, 4.51%, 12/10/42(3)		800,000		809,178
Commercial Mortgage Pass-Through Certificates, Series 2004 LB3A, Class A4 SEQ, VRN, 5.23%, 5/2/11(3)		600,000		615,989
Credit Suisse Mortgage Capital Certificates, Series 2007 TF2A, Class A1, VRN, 0.40%, 5/16/11, resets monthly off the 1-month LIBOR plus 0.18% with no caps(3)(4)		448,386		440,343
GE Capital Commercial Mortgage Corp., Series 2005 C3, Class A5, VRN, 4.98%, 5/2/11(3)		200,000		202,565
Greenwich Capital Commercial Funding Corp., Series 2005 GG3, Class A4, VRN, 4.80%, 5/2/11(3)		480,000		515,486
GS Mortgage Securities Corp. II, Series 2004 GG2, Class A6 SEQ, VRN, 5.40%, 5/2/11(3)		675,000		732,783
GS Mortgage Securities Corp. II, Series 2005 GG4, Class A4 SEQ, 4.76%, 7/10/39(3)		375,000		397,189
GS Mortgage Securities Corp. II, Series 2005 GG4, Class A4A SEQ, 4.75%, 7/10/39(3)		675,000		723,002
LB-UBS Commercial Mortgage Trust, Series 2004 C1, Class A4 SEQ, 4.57%, 1/15/31(3)		600,000		636,146
LB-UBS Commercial Mortgage Trust, Series 2004 C2, Class A4 SEQ, 4.37%, 3/15/36(3)		1,000,000		1,056,678
LB-UBS Commercial Mortgage Trust, Series 2004 C4, Class A4, VRN, 5.32%, 5/11/11(3)		300,000		323,045
LB-UBS Commercial Mortgage Trust, Series 2004 C8, Class AJ, VRN, 4.86%, 5/11/11(3)		125,000		130,522
LB-UBS Commercial Mortgage Trust, Series 2005 C2, Class A2 SEQ, 4.82%, 4/15/30(3)		130,859		130,974
LB-UBS Commercial Mortgage Trust, Series 2005 C5, Class AM, VRN, 5.02%, 5/11/11(3)		400,000		424,022
LB-UBS Commercial Mortgage Trust, Series 2005 C7, Class A4 SEQ, VRN, 5.20%, 5/11/11(3)		225,000		244,736

18

Shares/ Principal Amount Value

LB-UBS Commercial Mortgage Trust, Series 2005 C7, Class AM SEQ, VRN, 5.26%, 5/11/11(3)	$	400,000	$	427,699
Merrill Lynch Floating Trust, Series 2006-1, Class A1, VRN, 0.29%, 5/16/11, resets monthly off the 1-month LIBOR plus 0.07% with no caps(3)(4)		309,245		303,009
Morgan Stanley Capital I, Series 2001 T5, Class A4 SEQ, 6.39%, 10/15/35(3)		612,471		622,024
Morgan Stanley Capital I, Series 2003 T11, Class A3 SEQ, 4.85%, 6/13/41(3)		195,670		198,497
Morgan Stanley Capital I, Series 2005 HQ6, Class A2A SEQ, 4.88%, 8/13/42(3)		161,039		162,810
PNC Mortgage Acceptance Corp., Series 2001 C1, Class A2 SEQ, 6.36%, 3/12/34(3)		4,776		4,775
Wachovia Bank Commercial Mortgage Trust, Series 2003 C3, Class A2 SEQ, 4.87%, 2/15/35(3)		300,000		313,942
Wachovia Bank Commercial Mortgage Trust, Series 2004 C11, Class A3 SEQ, 4.72%, 1/15/41(3)		76,147		76,945
Wachovia Bank Commercial Mortgage Trust, Series 2004 C15, Class A3 SEQ, 4.50%, 10/15/41(3)		200,000		206,114
Wachovia Bank Commercial Mortgage Trust, Series 2005 C20, Class A5, VRN, 5.09%, 5/2/11(3)		272,783		276,474
Wachovia Bank Commercial Mortgage Trust, Series 2005 C20, Class A6A, VRN, 5.11%, 5/2/11(3)		1,000,000		1,037,365
TOTAL COMMERCIAL MORTGAGE-BACKED SECURITIES (Cost $11,327,973)				11,437,770
Collateralized Mortgage Obligations(6) — 1.5%
PRIVATE SPONSOR COLLATERALIZED MORTGAGE OBLIGATIONS — 1.2%
ABN Amro Mortgage Corp., Series 2003-4, Class A4, 5.50%, 3/25/33		279,224		289,835
Banc of America Alternative Loan Trust, Series 2007-2, Class 2A4, 5.75%, 6/25/37(3)		650,516		496,522
Banc of America Mortgage Securities, Inc., Series 2004-7, Class 7A1, 5.00%, 8/25/19(3)		218,020		219,930
Chase Mortgage Finance Corp., Series 2006 S4, Class A3, 6.00%, 12/25/36(3)		336,285		344,070
Citigroup Mortgage Loan Trust, Inc., Series 2005-4, Class A, VRN, 5.35%, 5/2/11(3)		426,617		422,707
Countrywide Home Loan Mortgage Pass-Through Trust, Series 2003 J13, Class 1A1 SEQ, 5.25%, 1/25/34(3)		48,033		47,983
Countrywide Home Loan Mortgage Pass-Through Trust, Series 2005-17, Class 1A11, 5.50%, 9/25/35(3)		270,514		269,813
Credit Suisse First Boston Mortgage Securities Corp., Series 2003 AR28, Class 2A1, VRN, 2.78%, 5/2/11(3)		608,696		568,048
MASTR Asset Securitization Trust, Series 2003-10, Class 3A1, 5.50%, 11/25/33(3)		374,962		396,385
PHHMC Mortgage Pass Through Certificates, Series 2007-6, Class A1, VRN, 6.18%, 5/2/11		408,439		428,341
Residential Funding Mortgage Securities I, Series 2006 S10, Class 2A1 SEQ, 5.50%, 10/25/21(3)		351,401		354,872
Wells Fargo Mortgage-Backed Securities Trust, Series 2004-1, Class A10, 5.50%, 2/25/34(3)		402,470		425,227
Wells Fargo Mortgage-Backed Securities Trust, Series 2004-4, Class A9, 5.50%, 5/25/34		229,408		241,712
Wells Fargo Mortgage-Backed Securities Trust, Series 2005 AR16, Class 4A6, VRN, 2.86%, 5/2/11(3)		223,827		222,399
Wells Fargo Mortgage-Backed Securities Trust, Series 2005-2, Class 1A1, SEQ, 5.50%, 4/25/35		338,582		344,807
Wells Fargo Mortgage-Backed Securities Trust, Series 2005-17, Class 1A1, 5.50%, 1/25/36		428,466		422,350

19

Shares/ Principal Amount Value

Wells Fargo Mortgage-Backed Securities Trust, Series 2005 AR14, Class A1, VRN, 5.37%, 5/2/11(3)	$	204,506	$	205,347
Wells Fargo Mortgage-Backed Securities Trust, Series 2006-10, Class A4 SEQ, 6.00%, 8/25/36		450,000		435,120
Wells Fargo Mortgage-Backed Securities Trust, Series 2007 AR10, Class 1A1, VRN, 6.18%, 5/2/11		302,657		305,058
				6,440,526
U.S. GOVERNMENT AGENCY COLLATERALIZED MORTGAGE OBLIGATIONS — 0.3%
FHLMC, Series 77, Class H, 8.50%, 9/15/20(3)		120,705		136,480
FHLMC, Series 2926, Class EW SEQ, 5.00%, 1/15/25(3)		1,200,000		1,316,051
				1,452,531
TOTAL COLLATERALIZED MORTGAGE OBLIGATIONS (Cost $7,831,364)				7,893,057
Municipal Securities — 1.1%
American Municipal Power-Ohio, Inc., Rev., (Building Bonds), 7.83%, 2/15/41(3)		60,000		71,222
American Municipal Power-Ohio, Inc., Rev., (Building Bonds), 5.94%, 2/15/47(3)		50,000		46,758
American Municipal Power-Ohio, Inc., Rev., (Building Bonds), 7.50%, 2/15/50(3)		75,000		80,923
Bay Area Toll Auth. Toll Bridge Rev., Series 2010 S1, (Building Bonds), 6.92%, 4/1/40(3)		270,000		291,303
California Educational Facilities Auth. Rev., Series 2009 A, (University of Southern California), 5.00%, 10/1/39(3)		280,000		282,668
California Educational Facilities Auth. Rev., Series 2009 B, (University of Southern California), 5.00%, 10/1/38(3)		140,000		141,421
California GO, (Building Bonds), 7.30%, 10/1/39(3)		110,000		121,793
California GO, (Building Bonds), 7.60%, 11/1/40(3)		30,000		34,308
Georgia Municipal Electric Auth. Rev., Series 2010 J, (Building Bonds), 6.64%, 4/1/57(3)		210,000		200,521
Illinois GO, 5.88%, 3/1/19(3)		240,000		249,238
Illinois GO, (Taxable Pension), 5.10%, 6/1/33(3)		300,000		252,393
Illinois GO, Series 2010-3, (Building Bonds), 6.725%, 4/1/35		110,000		110,318
Los Angeles Community College District GO, Series 2010 D, (Election of 2008), 6.68%, 8/1/36(3)		200,000		200,458
Los Angeles Department of Water & Power Rev., (Building Bonds), 5.72%, 7/1/39(3)		60,000		58,648
Metropolitan Atlanta Rapid Transit Auth. Rev., Series 2009 A, (Third Indenture), 5.00%, 7/1/39(3)		360,000		360,572
Metropolitan Transportation Auth. Rev., Series 2010 C1, (Building Bonds), 6.69%, 11/15/40(3)		105,000		110,852
Metropolitan Transportation Auth. Rev., Series 2010 E, (Building Bonds), 6.81%, 11/15/40(3)		150,000		161,760
Missouri Highways & Transportation Commission Rev., (Building Bonds), 5.45%, 5/1/33(3)		130,000		130,748
New Jersey State Turnpike Auth. Rev., Series 2009 F, (Building Bonds), 7.41%, 1/1/40(3)		100,000		116,619
New Jersey State Turnpike Auth. Rev., Series 2010 A, (Building Bonds), 7.10%, 1/1/41(3)		145,000		163,708
New York GO, Series 2010 F1, (Building Bonds), 6.27%, 12/1/37(3)		185,000		199,628
New York Municipal Water Finance Auth. Rev., Series 2011 GG, (Second General Resolution), 5.00%, 6/15/43(3)		400,000		397,128
Ohio Water Development Auth. Pollution Control Rev., Series 2010 B2, (Building Bonds), 4.88%, 12/1/34(3)		110,000		106,725

20

Shares/ Principal Amount Value

Oregon State Department of Transportation Highway User Tax Rev., Series 2010 A, (Building Bonds), 5.83%, 11/15/34(3)	$	70,000	$	74,019
Port Seattle Rev., Series 2010 B, (Intermediate Lien), 5.00%, 6/1/40(3)		210,000		201,600
Rutgers State University Rev., Series 2010 H, (Building Bonds), 5.67%, 5/1/40(3)		205,000		209,305
Sacramento Municipal Utility District Electric Rev., Series 2010 W, (Building Bonds), 6.16%, 5/15/36(3)		210,000		209,884
Salt River Agricultural Improvement & Power District Electric Rev., Series 2010 A, (Building Bonds), 4.84%, 1/1/41(3)		135,000		124,787
Salt River Agricultural Improvement & Power District Rev., Series 2008 A, (Electric System Distribution), 5.00%, 1/1/38(3)		65,000		65,638
Salt River Agricultural Improvement & Power District Rev., Series 2009 A, (Electric System Distribution), 5.00%, 1/1/39(3)		85,000		85,884
San Francisco City & County Public Utilities Water Commission Rev., Series 2010 B, (Building Bonds), 6.00%, 11/1/40(3)		220,000		223,676
Santa Clara Valley Transportation Auth. Sales Tax Rev., Series 2010 A, (Building Bonds), 5.88%, 4/1/32(3)		170,000		167,795
Texas GO, (Building Bonds), 5.52%, 4/1/39(3)		100,000		105,399
Triborough Bridge & Tunnel Auth. Rev., Series 2008 C, 5.00%, 11/15/38(3)		210,000		209,838
University Regiments Medical Center Rev., (Building Bonds), 6.55%, 5/15/48(3)		90,000		88,483
Washington GO, Series 2010 F, (Building Bonds), 5.14%, 8/1/40(3)		170,000		167,457
TOTAL MUNICIPAL SECURITIES (Cost $5,705,917)				5,823,477
Sovereign Governments and Agencies — 0.6%
BRAZIL — 0.2%
Brazilian Government International Bond, 5.875%, 1/15/19(3)		690,000		778,320
Brazilian Government International Bond, 5.625%, 1/7/41(3)		130,000		130,650
				908,970
CANADA ­— 0.1%
Hydro Quebec, 8.40%, 1/15/22(3)		145,000		197,589
Province of Ontario Canada, 5.45%, 4/27/16(3)		150,000		172,000
				369,589
GERMANY — 0.1%
KfW, 4.125%, 10/15/14(3)		240,000		263,534
ITALY(2)
Republic of Italy, 3.125%, 1/26/15(3)		220,000		224,978
MEXICO — 0.1%
United Mexican States, 5.625%, 1/15/17(3)		90,000		100,800
United Mexican States, 5.95%, 3/19/19(3)		420,000		473,970
United Mexican States, 5.125%, 1/15/20(3)		130,000		138,060
United Mexican States, 6.05%, 1/11/40(3)		120,000		125,100
				837,930
POLAND — 0.1%
Republic of Poland, 5.125%, 4/21/21(3)		280,000		281,820
SOUTH KOREA(2)
Export-Import Bank of Korea, 3.75%, 10/20/16		160,000		160,548
TOTAL SOVEREIGN GOVERNMENTS & AGENCIES (Cost $2,920,752)				3,047,369
Temporary Cash Investments — 1.1%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares(3) (Cost $6,016,840)		6,016,840		6,016,840
TOTAL INVESTMENT SECURITIES — 100.0% (Cost $457,607,333)				534,519,426
OTHER ASSETS AND LIABILITIES(2)				120,614
TOTAL NET ASSETS — 100.0%			$	534,640,040

21

Futures Contracts
Contracts Purchased		Expiration Date	Underlying Face Amount at Value	Unrealized Gain (Loss)
52	U.S. Long Bond	June 2011	$6,363,500	$125,883
Contracts Sold		Expiration Date	Underlying Face Amount at Value	Unrealized Gain (Loss)
162	U.S. Treasury 2-Year Notes	June 2011	$35,498,250	$(178,031)

Swap Agreements
Notional Amount	Description of Agreement	Premiums Paid (Received)	Value
CREDIT DEFAULT – BUY PROTECTION
$4,400,000	Pay quarterly a fixed rate equal to 1.00% per annum multiplied by the notional amount and receive from Bank of America N.A. upon each default event of one of the issues of CDX North America Investment Grade 16 Index, par value of the proportional notional amount. Expires June 2016.	$(6,314)	$(31,039)

Notes to Schedule of Investments

CDX = Credit Derivative Indexes

Equivalent = Security whose principal payments are backed by the full faith and credit of the United States

FHLMC = Federal Home Loan Mortgage Corporation

FNMA = Federal National Mortgage Association

GNMA = Government National Mortgage Association

GO = General Obligation

LB-UBS = Lehman Brothers, Inc. — UBS AG

LIBOR = London Interbank Offered Rate

MASTR = Mortgage Asset Securitization Transactions, Inc.

resets = The frequency with which a security’s coupon changes, based on current market conditions or an underlying index. The more frequently a security resets, the less risk the investor is taking that the coupon will vary significantly from current market rates.

SEQ = Sequential Payer

VRN = Variable Rate Note. Interest reset date is indicated. Rate shown is effective at the period end.

(1) Non-income producing.

(2) Category is less than 0.05% of total net assets.

(3) Security, or a portion thereof, has been segregated for when-issued securities, futures contracts and/or swap agreements. At the period end, the aggregate value of securities pledged was $47,276,000.

(4) Security was purchased under Rule 144A of the Securities Act of 1933 or is a private placement and, unless registered under the Act or exempted from registration, may only be sold to qualified institutional investors. The aggregate value of these securities at the period end was $3,576,857 which represented 0.7% of total net assets.

(5) When-issued security.

(6) Final maturity indicated, unless otherwise noted.

(7) The debt is guaranteed under the Federal Deposit Insurance Corporation’s (FDIC) Temporary Liquidity Guarantee Program and is backed by the full faith and credit of the United States. The expiration date of the FDIC’s guarantee is the earlier of the maturity date of the debt or December 31, 2012.

See Notes to Financial Statements.

22

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $457,607,333)	$	534,519,426
Cash		40,984
Receivable for investments sold		5,653,823
Receivable for capital shares sold		74,767
Receivable for variation margin on futures contracts		13,000
Dividends and interest receivable		1,887,874
		542,189,874
Liabilities
Payable for investments purchased		6,782,586
Payable for capital shares redeemed		344,477
Payable for variation margin on futures contracts		5,063
Accrued management fees		386,669
Swap agreements, at value (including net premiums paid (received) of $(6,314))		31,039
		7,549,834
Net Assets	$	534,640,040
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	479,134,040
Undistributed net investment income		715,040
Accumulated net realized loss		(22,044,260	)
Net unrealized appreciation		76,835,220
	$	534,640,040

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$523,960,745	32,012,534	$16.37
Institutional Class, $0.01 Par Value	$10,679,295	652,394	$16.37

See Notes to Financial Statements.

23

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $1,577)	$	3,006,173
Interest (net of foreign taxes withheld of $188)		3,961,302
		6,967,475
Expenses:
Management fees		2,284,516
Directors’ fees and expenses		12,432
		2,296,948
Net investment income (loss)		4,670,527
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		25,469,084
Futures contract transactions		(249,699	)
Swap agreement transactions		502
		25,219,887
Change in net unrealized appreciation (depreciation) on:
Investments		19,188,366
Futures contracts		111,273
Swap agreements		(24,725	)
		19,274,914
Net realized and unrealized gain (loss)		44,494,801
Net Increase (Decrease) in Net Assets Resulting from Operations	$	49,165,328

See Notes to Financial Statements.

24

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	4,670,527		$	8,968,987
Net realized gain (loss)		25,219,887			33,534,651
Change in net unrealized appreciation (depreciation)		19,274,914			14,794,715
Net increase (decrease) in net assets resulting from operations		49,165,328			57,298,353
Distributions to Shareholders
From net investment income:
Investor Class		(4,751,511	)		(9,006,369	)
Institutional Class		(91,243	)		(137,117	)
Decrease in net assets from distributions		(4,842,754	)		(9,143,486	)
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		(3,286,400	)		(19,983,287	)
Net increase (decrease) in net assets		41,036,174			28,171,580
Net Assets
Beginning of period		493,603,866			465,432,286
End of period	$	534,640,040		$	493,603,866
Undistributed net investment income	$	715,040		$	887,267

See Notes to Financial Statements.

25

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Balanced Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth and current income. The fund pursues its objectives by investing approximately 60% of its assets in equity securities and the remainder in bonds and other fixed-income securities.

The fund is authorized to issue the Investor Class and the Institutional Class. The share classes differ principally in their respective distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing in greater than 60 days at the time of purchase are valued at the evaluated mean as provided by independent pricing services or at the mean of the most recent bid and asked prices as provided by investment dealers. Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Exchange-traded futures contracts are valued at the settlement price as provided by the appropriate clearing corporation. Swap agreements are valued at an evaluated price as provided by independent pricing services or investment dealers.

26

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income less foreign taxes withheld, if any, is recorded on the accrual basis and includes paydown gain (loss) and accretion of discounts and amortization of premiums.

When-Issued and Forward Commitments — The fund may engage in securities transactions on a when-issued or forward commitment basis. In these transactions, the securities’ prices and yields are fixed on the date of the commitment. In a when-issued transaction, the payment and delivery are scheduled for a future date and during this period, securities are subject to market fluctuations. In a forward commitment transaction, the fund may sell a security and at the same time make a commitment to purchase the same security at a future date at a specified price. Conversely, the fund may purchase a security and at the same time make a commitment to sell the same security at a future date at a specified price. These types of transactions are executed simultaneously in what are known as “roll” transactions. The fund will segregate cash, cash equivalents or other appropriate liquid securities on its records in amounts sufficient to meet the purchase price. The fund accounts for “roll” transactions as purchases and sales.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income, if any, are generally declared and paid quarterly. Distributions from net realized gains, if any, are generally declared and paid annually.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

27

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with American Century Investment Management, Inc. (ACIM) (the investment advisor), under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The annual management fee schedule ranges from 0.800% to 0.900% for the Investor Class. The Institutional Class is 0.200% less at each point within the range. The effective annual management fee for each class for the six months ended April 30, 2011 was 0.90% for the Investor Class and 0.70% for the Institutional Class.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, American Century Investment Services, Inc., and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a securities lending agreement with JPMorgan Chase Bank (JPMCB) and a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMCB is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases of investment securities, excluding short-term investments, for the six months ended April 30, 2011 totaled $241,513,628, of which $87,918,157 represented U.S. Treasury and Government Agency obligations.

Sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 totaled $239,391,811, of which $70,988,715 represented U.S. Treasury and Government Agency obligations.

28

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		250,000,000						250,000,000
Sold		1,342,123		$	21,018,941			2,377,402		$	34,180,361
Issued in reinvestment of distributions		297,082			4,620,186			607,236			8,759,310
Redeemed		(2,057,938	)		(32,149,718	)		(4,356,884	)		(62,587,920	)
		(418,733	)		(6,510,591	)		(1,372,246	)		(19,648,249	)
Institutional Class/Shares Authorized		15,000,000						15,000,000
Sold		894,703			13,911,223			55,917			817,168
Issued in reinvestment of distributions		5,856			91,243			9,507			137,117
Redeemed		(683,423	)		(10,778,275	)		(90,124	)		(1,289,323	)
		217,136			3,224,191			(24,700	)		(335,038	)
Net increase (decrease)		(201,597	)	$	(3,286,400	)		(1,396,946	)	$	(19,983,287	)

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

29

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1			Level 2			Level 3
Investment Securities
Common Stocks	$	323,116,557			—			—
U.S. Government Agency Mortgage-Backed Securities		—		$	56,005,625			—
Corporate Bonds		—			55,686,237			—
U.S. Treasury Securities		—			50,915,343			—
U.S. Government Agency Securities and Equivalents		—			14,577,151			—
Commercial Mortgage-Backed Securities		—			11,437,770			—
Collateralized Mortgage Obligations		—			7,893,057			—
Municipal Securities		—			5,823,477			—
Sovereign Governments and Agencies		—			3,047,369			—
Temporary Cash Investments		6,016,840			—			—
Total Value of Investment Securities	$	329,133,397		$	205,386,029			—
Other Financial Instruments
Futures Contracts	$	(52,148	)		—			—
Swap Agreements		—		$	(24,725	)		—
Total Unrealized Gain (Loss) on Other Financial Instruments	$	(52,148	)	$	(24,725	)		—

7. Derivative Instruments

Credit Risk — The fund is subject to credit risk in the normal course of pursuing its investment objectives. The value of a bond generally declines as the credit quality of its issuer declines. Credit default swap agreements enable a fund to buy/sell protection against a credit event of a specific issuer or index. A fund may attempt to enhance returns by selling protection or attempt to mitigate credit risk by buying protection. The buyer/seller of credit protection against a security or basket of securities may pay/receive an up-front or periodic payment to compensate for/against potential default events. A fund will segregate cash, cash equivalents or other appropriate liquid securities on its records in amounts sufficient to meet requirements. Changes in value, including the periodic amounts of interest to be paid or received on swap agreements, are recorded as unrealized appreciation (depreciation) on swap agreements. Realized gain or loss is recorded upon receipt or payment of a periodic settlement or termination of swap agreements. Net realized and unrealized gains or losses occurring during the holding period of swap agreements are a component of net realized gain (loss) on swap agreement transactions and change in net unrealized appreciation (depreciation) on swap agreements, respectively. The risks of entering into swap agreements include the possible lack of liquidity, failure of the counterparty to meet its obligations, and that there may be unfavorable changes in the underlying investments or instruments. The fund began investing in credit risk derivative instruments in March 2011. The credit risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume since March 2011.

Equity Price Risk — The fund is subject to equity price risk in the normal course of pursuing its investment objectives. A fund may enter into futures contracts based on an equity index in order to manage its exposure to changes in market conditions. A fund may purchase futures contracts to gain exposure to increases in market value or sell futures contracts to protect against a decline in market value. Upon entering into a futures contract, a fund is required to deposit either cash or securities in an amount equal to a certain percentage of the contract value (initial margin). Subsequent payments (variation margin) are made or received daily, in cash, by a fund. The variation margin is equal to the daily change in the contract value and is recorded as unrealized gains and losses. A fund recognizes a realized gain or loss when the contract is closed or expires. Net realized and unrealized gains or losses occurring during the holding period of futures contracts are a component

30

of net realized gain (loss) on futures contract transactions and change in net unrealized appreciation (depreciation) on futures contracts, respectively. One of the risks of entering into futures contracts is the possibility that the change in value of the contract may not correlate with the changes in value of the underlying securities. During the period, the fund infrequently purchased equity price risk derivative instruments for temporary investment purposes.

Interest Rate Risk — The fund is subject to interest rate risk in the normal course of pursuing its investment objectives. The value of bonds generally declines as interest rates rise. A fund may enter into futures contracts based on a bond index or a specific underlying security. A fund may purchase futures contracts to gain exposure to increases in market value or sell futures contracts to protect against a decline in market value. Upon entering into a futures contract, a fund will segregate cash, cash equivalents or other appropriate liquid securities on its records in amounts sufficient to meet requirements. Subsequent payments (variation margin) are made or received daily, in cash, by a fund. The variation margin is equal to the daily change in the contract value and is recorded as unrealized gains and losses. A fund recognizes a realized gain or loss when the futures contract is closed or expires. Net realized and unrealized gains or losses occurring during the holding period of futures contracts are a component of net realized gain (loss) on futures contract transactions and change in net unrealized appreciation (depreciation) on futures contracts, respectively. One of the risks of entering into futures contracts is the possibility that the change in value of the contract may not correlate with the changes in value of the underlying securities. The interest rate risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

Value of Derivative Instruments as of April 30, 2011
	Asset Derivatives				Liability Derivatives
Type of Risk Exposure	Location on Statement of Assets and Liabilities	Value			Location on Statement of Assets and Liabilities	Value
Credit Risk	Swap agreements		—		Swap agreements	$	31,039
Interest Rate Risk	Receivable for variation margin on futures contracts	$	13,000		Payable for variation margin on futures contracts		5,063
		$	13,000			$	36,102
Effect of Derivative Instruments on the Statement of Operations for the Six Months Ended April 30, 2011
	Net Realized Gain (Loss)				Change in Net Unrealized Appreciation (Depreciation)
Type of Risk Exposure	Location on Statement of Operations	Value			Location on Statement of Operations	Value
Credit Risk	Net realized gain (loss) on swap agreement transactions	$	502		Change in net unrealized appreciation (depreciation) on swap agreements	$	(24,725	)
Equity Price Risk	Net realized gain (loss) on futures contract transactions		95,768		Change in net unrealized appreciation (depreciation) on futures contracts		—
Interest Rate Risk	Net realized gain (loss) on futures contract transactions		(345,467	)	Change in net unrealized appreciation (depreciation) on futures contracts		111,273
		$	(249,197	)		$	86,548

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8. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	464,231,002
Gross tax appreciation of investments	$	72,488,663
Gross tax depreciation of investments		(2,200,239	)
Net tax appreciation (depreciation) of investments	$	70,288,424

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(39,619,923), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers expire in 2017.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

32

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	15.02		$	13.58		$	12.66		$	17.47		$	17.03		$	16.52
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.14			0.27			0.28			0.37			0.35			0.35
Net Realized and    Unrealized Gain (Loss)		1.36			1.44			0.93			(3.69	)		1.11			1.40
Total From    Investment Operations		1.50			1.71			1.21			(3.32	)		1.46			1.75
Distributions
From Net    Investment Income		(0.15	)		(0.27	)		(0.29	)		(0.37	)		(0.36	)		(0.35	)
From Net    Realized Gains		—			—			—			(1.12	)		(0.66	)		(0.89	)
Total Distributions		(0.15	)		(0.27	)		(0.29	)		(1.49	)		(1.02	)		(1.24	)
Net Asset Value, End of Period	$	16.37		$	15.02		$	13.58		$	12.66		$	17.47		$	17.03
Total Return(3)		10.03	%		12.70	%		9.81	%		(20.52	)%		8.92	%		11.04	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.90	%(4)		0.91	%		0.90	%		0.90	%		0.90	%		0.90	%
Ratio of Net Investment Income (Loss) to Average Net Assets		1.83	%(4)		1.85	%		2.21	%		2.42	%		2.08	%		2.13	%
Portfolio Turnover Rate		48	%		69	%		110	%		153	%		161	%		197	%
Net Assets, End of Period (in millions)	$	524		$	487		$	459		$	440		$	636		$	637

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

33

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	15.02		$	13.59		$	12.66		$	17.47		$	17.04		$	16.53
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.15			0.29			0.30			0.39			0.39			0.38
Net Realized and    Unrealized Gain (Loss)		1.36			1.44			0.94			(3.68	)		1.09			1.40
Total From    Investment Operations		1.51			1.73			1.24			(3.29	)		1.48			1.78
Distributions
From Net    Investment Income		(0.16	)		(0.30	)		(0.31	)		(0.40	)		(0.39	)		(0.38	)
From Net    Realized Gains		—			—			—			(1.12	)		(0.66	)		(0.89	)
Total Distributions		(0.16	)		(0.30	)		(0.31	)		(1.52	)		(1.05	)		(1.27	)
Net Asset Value, End of Period	$	16.37		$	15.02		$	13.59		$	12.66		$	17.47		$	17.04
Total Return(3)		10.14	%		12.84	%		10.11	%		(20.37	)%		9.07	%		11.26	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.70	%(4)		0.71	%		0.70	%		0.70	%		0.70	%		0.70	%
Ratio of Net Investment Income (Loss) to Average Net Assets		2.03	%(4)		2.05	%		2.41	%		2.62	%		2.28	%		2.33	%
Portfolio Turnover Rate		48	%		69	%		110	%		153	%		161	%		197	%
Net Assets, End of Period (in thousands)	$	10,679		$	6,538		$	6,249		$	5,927		$	1,338		$	1,228

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

34

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

35

Notes

36

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

��

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71831   1106

SEMIANNUAL REPORT     |      APRIL 30, 2011

Capital Value Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	11
Statement of Operations	12
Statement of Changes in Net Assets	13
Notes to Financial Statements	14
Financial Highlights	19
Additional Information	22

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	10 years	Since Inception	Inception Date
Investor Class    Return After-Tax       on Distributions(2)    Return After-Tax on       Distributions and       Sale of Shares(2)	ACTIX	15.42%(3)    15.15%(3)    10.34%(3)	13.25%(3)    12.98%(3)    8.92%(3)	-0.06%  -0.52%  -0.07%	3.38% 2.98% 2.85%	4.37% 3.94% 3.69%	3/31/99
Russell 1000 Value Index	—	17.29%	15.24%	1.40%	4.31%	4.52%	—
Institutional Class    Return After-Tax       on Distributions(2)    Return After-Tax on       Distributions and       Sale of Shares(2)	ACPIX	15.45%(3)    15.14%(3)    10.39%(3)	13.47%(3)    13.17%(3)    9.10%(3)	0.15% -0.35%  0.10%	— — —	3.76% 3.33% 3.19%	3/1/02
A Class(4)    No sales charge*    With sales charge*    Return After-Tax       on Distributions(2)    Return After-Tax on       Distributions and       Sale of Shares(2)	ACCVX	15.15%(3)    8.51%(3) 8.30%(3) 5.78%(3)	12.79%(3)    6.24%(3) 6.03%(3) 4.30%(3)	-0.31%  -1.49%  -1.92%  -1.28%	— — — —	5.28% 4.49% 4.14% 3.88%	5/14/03

* Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

(2) After-tax returns are calculated with sales charge, as applicable, using the historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

(3) Returns would have been lower if a portion of the management fee had not been waived.

(4) Prior to March 1, 2010, the A Class was referred to as the Advisor Class and did not have a front-end sales charge. Performance prior to that date has been adjusted to reflect this charge.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class
1.11%	0.91%	1.36%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Chevron Corp.	4.3%
JPMorgan Chase & Co.	3.6%
AT&T, Inc.	3.5%
Johnson & Johnson	3.5%
General Electric Co.	3.4%
Pfizer, Inc.	3.3%
Wells Fargo & Co.	3.0%
Procter & Gamble Co. (The)	2.9%
Merck & Co., Inc.	2.7%
Exxon Mobil Corp.	2.4%
Top Five Industries	% of net assets
Oil, Gas & Consumable Fuels	11.4%
Pharmaceuticals	10.4%
Diversified Financial Services	7.8%
Insurance	7.6%
Diversified Telecommunication Services	6.0%
Types of Investments in Portfolio	% of net assets
Common Stocks	99.1%
Temporary Cash Investments	0.9%
Other Assets and Liabilities	—*

*Category is less than 0.05% of total net assets.

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period(1) 11/1/10 – 4/30/11	Annualized Expense Ratio(1)
Actual
Investor Class (after waiver)	$1,000	$1,154.20	$5.39	1.01%
Investor Class (before waiver)	$1,000	$1,154.20(2)	$5.93	1.11%
Institutional Class (after waiver)	$1,000	$1,154.50	$4.33	0.81%
Institutional Class (before waiver)	$1,000	$1,154.50(2)	$4.86	0.91%
A Class (after waiver)	$1,000	$1,151.50	$6.72	1.26%
A Class (before waiver)	$1,000	$1,151.50(2)	$7.25	1.36%
Hypothetical
Investor Class (after waiver)	$1,000	$1,019.79	$5.06	1.01%
Investor Class (before waiver)	$1,000	$1,019.29	$5.56	1.11%
Institutional Class (after waiver)	$1,000	$1,020.78	$4.06	0.81%
Institutional Class (before waiver)	$1,000	$1,020.28	$4.56	0.91%
A Class (after waiver)	$1,000	$1,018.55	$6.31	1.26%
A Class (before waiver)	$1,000	$1,018.05	$6.80	1.36%

(1) Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

(2) Ending account value assumes the return earned after waiver and would have been lower if a portion of the management fee had not been waived.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 99.1%
AEROSPACE & DEFENSE — 1.7%
Honeywell International, Inc.		4,900	$	300,027
Lockheed Martin Corp.		10,100		800,425
Northrop Grumman Corp.		21,000		1,335,810
				2,436,262
AIRLINES — 0.3%
Southwest Airlines Co.		32,300		379,525
BEVERAGES — 1.4%
Coca-Cola Co. (The)		5,800		391,268
PepsiCo, Inc.		24,700		1,701,583
				2,092,851
BIOTECHNOLOGY — 2.3%
Amgen, Inc.(1)		41,400		2,353,590
Gilead Sciences, Inc.(1)		23,800		924,392
				3,277,982
CAPITAL MARKETS — 3.9%
Ameriprise Financial, Inc.		12,900		800,574
Bank of New York Mellon Corp. (The)		47,200		1,366,912
Goldman Sachs Group, Inc. (The)		15,800		2,385,958
Morgan Stanley		43,400		1,134,910
				5,688,354
CHEMICALS — 0.6%
E.I. du Pont de Nemours & Co.		16,700		948,393
COMMERCIAL BANKS — 5.6%
PNC Financial Services Group, Inc.		27,500		1,714,350
U.S. Bancorp.		80,100		2,068,182
Wells Fargo & Co.		151,300		4,404,343
				8,186,875
COMMERCIAL SERVICES & SUPPLIES — 0.5%
Avery Dennison Corp.		16,600		692,884
COMMUNICATIONS EQUIPMENT — 1.0%
Cisco Systems, Inc.		79,100		1,388,996
COMPUTERS & PERIPHERALS — 1.2%
Hewlett-Packard Co.		37,800		1,525,986
Western Digital Corp.(1)		6,700		266,660
				1,792,646
DIVERSIFIED FINANCIAL SERVICES — 7.8%
Bank of America Corp.		264,000		3,241,920
Citigroup, Inc.(1)		627,000		2,877,930
JPMorgan Chase & Co.		114,200		5,210,946
				11,330,796
DIVERSIFIED TELECOMMUNICATION SERVICES — 6.0%
AT&T, Inc.		165,100		5,137,912
CenturyLink, Inc.		18,200		742,196
Verizon Communications, Inc.		75,800		2,863,724
				8,743,832
ELECTRIC UTILITIES — 2.0%
American Electric Power Co., Inc.		36,500		1,331,520
Exelon Corp.		14,200		598,530
PPL Corp.		35,800		981,994
				2,912,044
ENERGY EQUIPMENT & SERVICES — 1.1%
Baker Hughes, Inc.		4,200		325,122
National Oilwell Varco, Inc.		6,100		467,809
Transocean Ltd.(1)		11,300		822,075
				1,615,006
FOOD & STAPLES RETAILING — 5.0%
CVS Caremark Corp.		48,600		1,761,264
Kroger Co. (The)		59,200		1,439,152
SYSCO Corp.		28,900		835,499
Walgreen Co.		18,600		794,592
Wal-Mart Stores, Inc.		44,200		2,430,116
				7,260,623
FOOD PRODUCTS — 1.5%
Kraft Foods, Inc., Class A		62,600		2,102,108
Unilever NV New York Shares		4,000		132,000
				2,234,108
HEALTH CARE EQUIPMENT & SUPPLIES — 0.8%
Medtronic, Inc.		28,700		1,198,225
HEALTH CARE PROVIDERS & SERVICES — 1.9%
Aetna, Inc.		21,000		868,980
HCA Holdings, Inc.(1)		4,000		131,200
Quest Diagnostics, Inc.		11,800		665,284
WellPoint, Inc.		14,500		1,113,455
				2,778,919
HOUSEHOLD PRODUCTS — 3.7%
Clorox Co.		5,200		362,232
Energizer Holdings, Inc.(1)		9,668		730,224
Procter & Gamble Co. (The)		65,300		4,237,970
				5,330,426
INDEPENDENT POWER PRODUCERS & ENERGY TRADERS — 0.3%
NRG Energy, Inc.(1)		17,100		413,820

8

Shares Value

INDUSTRIAL CONGLOMERATES — 4.0%
General Electric Co.	242,200	$	4,952,990
Tyco International Ltd.	17,200		838,328
			5,791,318
INSURANCE — 7.6%
Allstate Corp. (The)	54,600		1,847,664
Berkshire Hathaway, Inc., Class B(1)	16,400		1,366,120
Chubb Corp. (The)	29,700		1,936,143
Loews Corp.	35,500		1,571,230
MetLife, Inc.	11,600		542,764
Principal Financial Group, Inc.	29,500		995,625
Torchmark Corp.	12,200		816,424
Travelers Cos., Inc. (The)	32,200		2,037,616
			11,113,586
IT SERVICES — 1.2%
Fiserv, Inc.(1)	9,800		600,838
International Business Machines Corp.	6,600		1,125,828
			1,726,666
MACHINERY — 1.3%
Dover Corp.	8,900		605,556
Ingersoll-Rand plc	24,800		1,252,400
			1,857,956
MEDIA — 5.4%
CBS Corp., Class B	37,700		950,794
Comcast Corp., Class A	105,300		2,763,072
Time Warner Cable, Inc.	10,600		828,178
Time Warner, Inc.	48,900		1,851,354
Viacom, Inc., Class B	27,800		1,422,248
			7,815,646
METALS & MINING — 0.7%
Freeport-McMoRan Copper & Gold, Inc.	4,000		220,120
Nucor Corp.	18,000		845,280
			1,065,400
MULTILINE RETAIL — 1.4%
Kohl’s Corp.	20,600		1,085,826
Macy’s, Inc.	41,500		992,265
			2,078,091
MULTI-UTILITIES — 0.9%
PG&E Corp.	28,400		1,308,672
OIL, GAS & CONSUMABLE FUELS — 11.4%
Apache Corp.	12,400		1,653,788
Chevron Corp.	56,600		6,194,304
ConocoPhillips	33,700		2,659,941
Exxon Mobil Corp.	39,000		3,432,000
Occidental Petroleum Corp.	9,500		1,085,755
Total SA ADR	14,400		924,912
Valero Energy Corp.	20,500		580,150
			16,530,850
PAPER & FOREST PRODUCTS — 0.5%
International Paper Co.	23,500		725,680
PHARMACEUTICALS — 10.4%
Abbott Laboratories	26,100		1,358,244
Johnson & Johnson	77,500		5,093,300
Merck & Co., Inc.	109,000		3,918,550
Pfizer, Inc.	229,600		4,812,416
			15,182,510
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 1.6%
Applied Materials, Inc.	31,900		500,511
Intel Corp.	63,900		1,481,841
Marvell Technology Group Ltd.(1)	26,500		408,895
			2,391,247
SOFTWARE — 2.8%
Activision Blizzard, Inc.	56,200		640,118
Microsoft Corp.	99,200		2,581,184
Oracle Corp.	24,200		872,410
			4,093,712
TEXTILES, APPAREL & LUXURY GOODS — 0.4%
VF Corp.	5,500		553,080
TOBACCO — 0.9%
Altria Group, Inc.	47,700		1,280,268
TOTAL COMMON STOCKS (Cost $108,319,874)			144,217,249
Temporary Cash Investments — 0.9%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	50,637		50,637
Repurchase Agreement, Goldman Sachs Group, Inc., (collateralized by various U.S. Treasury obligations, 6.750%-7.625%, 11/15/22-8/15/26, valued at $1,327,696), in a joint trading account at 0.01%, dated 4/29/11, due 5/2/11 (Delivery value $1,300,001)			1,300,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $1,350,637)			1,350,637
TOTAL INVESTMENT SECURITIES — 100.0% (Cost $109,670,511)			145,567,886
OTHER ASSETS AND LIABILITIES(2)			2,525
TOTAL NET ASSETS — 100.0%		$	145,570,411

9

Notes to Schedule of Investments

ADR = American Depositary Receipt

(1) Non-income producing.

(2) Category is less than 0.05% of total net assets.

See Notes to Financial Statements.

10

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $109,670,511)	$	145,567,886
Cash		28,950
Receivable for investments sold		427,361
Receivable for capital shares sold		56,488
Dividends and interest receivable		208,784
		146,289,469
Liabilities
Payable for investments purchased		358,592
Payable for capital shares redeemed		241,768
Accrued management fees		117,803
Distribution and service fees payable		895
		719,058
Net Assets	$	145,570,411
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	133,071,019
Undistributed net investment income		624,116
Accumulated net realized loss		(24,022,099	)
Net unrealized appreciation		35,897,375
	$	145,570,411

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$137,225,568	21,091,727	$6.51
Institutional Class, $0.01 Par Value	$3,919,024	602,146	$6.51
A Class, $0.01 Par Value	$4,425,819	680,929	$6.50*

*Maximum offering price $6.90 (net asset value divided by 0.9425)

See Notes to Financial Statements.

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Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends	$	1,731,069
Interest		232
		1,731,301
Expenses:
Management fees		789,768
Distribution and service fees — A Class		5,291
Directors’ fees and expenses		3,651
		798,710
Fees waived		(72,167	)
		726,543
Net investment income (loss)		1,004,758
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on investment transactions		8,241,327
Change in net unrealized appreciation (depreciation) on investments		11,546,077
Net realized and unrealized gain (loss)		19,787,404
Net Increase (Decrease) in Net Assets Resulting from Operations	$	20,792,162

See Notes to Financial Statements.

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Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	1,004,758		$	2,559,390
Net realized gain (loss)		8,241,327			1,237,403
Change in net unrealized appreciation (depreciation)		11,546,077			11,294,260
Net increase (decrease) in net assets resulting from operations		20,792,162			15,091,053
Distributions to Shareholders
From net investment income:
Investor Class		(2,149,583	)		(2,997,083	)
Institutional Class		(71,311	)		(160,186	)
A Class		(56,838	)		(74,678	)
Decrease in net assets from distributions		(2,277,732	)		(3,231,947	)
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		(18,091,392	)		(38,059,437	)
Net increase (decrease) in net assets		423,038			(26,200,331	)
Net Assets
Beginning of period		145,147,373			171,347,704
End of period	$	145,570,411		$	145,147,373
Undistributed net investment income	$	624,116		$	1,897,090

See Notes to Financial Statements.

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Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Capital Value Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing primarily in common stocks of medium to large companies that management believes to be undervalued at the time of purchase. The fund also seeks to minimize the impact of federal income taxes on shareholder returns by attempting to minimize taxable distributions to shareholders.

The fund is authorized to issue the Investor Class, the Institutional Class and the A Class (formerly Advisor Class). The A Class may incur an initial sales charge. The A Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost.

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited

14

to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

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3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The annual management fee schedule ranges from 0.90% to 1.10% for the Investor Class and A Class. The Institutional Class is 0.20% less at each point within the range. During the six months ended April 30, 2011, the investment advisor voluntarily agreed to waive 0.10% of its management fee. The investment advisor expects the fee waiver to continue through July 31, 2011, and cannot terminate it without the approval of the Board of Directors. The total amount of the waiver for each class for the six months ended April 30, 2011 was $68,017, $2,033 and $2,117 for the Investor Class, Institutional Class and A Class, respectively. The effective annual management fee before waiver for each class for the six months ended April 30, 2011 was 1.10% for the Investor Class and A Class and 0.90% for the Institutional Class. The effective annual management fee after waiver for each class for the six months ended April 30, 2011 was 1.00% for the Investor Class and A Class and 0.80% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a Master Distribution and Individual Shareholder Services Plan for the A Class, pursuant to Rule 12b-1 of the 1940 Act. The plan provides that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The fees are computed and accrued daily based on A Class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a securities lending agreement with JPMorgan Chase Bank (JPMCB) and a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMCB is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $16,977,340 and $36,861,569, respectively.

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5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		200,000,000						200,000,000
Sold		1,018,769		$	6,235,843			1,955,169		$	10,850,916
Issued in reinvestment of distributions		325,518			1,927,066			451,737			2,507,145
Redeemed		(4,174,878	)		(25,417,407	)		(8,285,413	)		(45,868,497	)
		(2,830,591	)		(17,254,498	)		(5,878,507	)		(32,510,436	)
Institutional Class/Shares Authorized		15,000,000						15,000,000
Sold		177,260			1,079,360			390,590			2,170,864
Issued in reinvestment of distributions		7,940			47,007			8,418			46,637
Redeemed		(276,956	)		(1,705,189	)		(1,214,410	)		(6,689,788	)
		(91,756	)		(578,822	)		(815,402	)		(4,472,287	)
A Class/Shares Authorized		50,000,000						50,000,000
Sold		75,470			463,963			116,151			650,738
Issued in reinvestment of distributions		9,570			56,655			13,441			74,594
Redeemed		(126,785	)		(778,690	)		(327,159	)		(1,802,046	)
		(41,745	)		(258,072	)		(197,567	)		(1,076,714	)
Net increase (decrease)		(2,964,092	)	$	(18,091,392	)		(6,891,476	)	$	(38,059,437	)

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2		Level 3
Investment Securities
Common Stocks	$	144,217,249		—		—
Temporary Cash Investments		50,637	$	1,300,000		—
Total Value of Investment Securities	$	144,267,886	$	1,300,000		—

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7. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	111,993,288
Gross tax appreciation of investments	$	37,142,810
Gross tax depreciation of investments		(3,568,212	)
Net tax appreciation (depreciation) of investments	$	33,574,598

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(30,135,109), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers of $(5,984,250) and $(24,150,859) expire in 2016 and 2017, respectively.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

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Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	5.73		$	5.32		$	5.17		$	8.78		$	8.23		$	7.15
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.04			0.09			0.11			0.14			0.13			0.12
Net Realized and    Unrealized Gain (Loss)		0.83			0.42			0.21			(3.28	)		0.65			1.14
Total From    Investment Operations		0.87			0.51			0.32			(3.14	)		0.78			1.26
Distributions
From Net    Investment Income		(0.09	)		(0.10	)		(0.17	)		(0.13	)		(0.12	)		(0.10	)
From Net    Realized Gains		—			—			—			(0.34	)		(0.11	)		(0.08	)
Total Distributions		(0.09	)		(0.10	)		(0.17	)		(0.47	)		(0.23	)		(0.18	)
Net Asset Value, End of Period	$	6.51		$	5.73		$	5.32		$	5.17		$	8.78		$	8.23
Total Return(3)		15.42	%		9.69	%		6.85	%		(37.52	)%		9.66	%		18.03	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.01	%(4)		1.09	%		1.10	%		1.10	%		1.10	%		1.10	%
Ratio of Operating Expenses to Average Net Assets (Before Expense Waiver)		1.11	%(4)		1.11	%		1.10	%		1.10	%		1.10	%		1.10	%
Ratio of Net Investment Income (Loss) to Average Net Assets		1.39	%(4)		1.56	%		2.33	%		1.98	%		1.52	%		1.55	%
Ratio of Net Investment Income (Loss) to Average Net Assets (Before Expense Waiver)		1.29	%(4)		1.54	%		2.33	%		1.98	%		1.52	%		1.55	%
Portfolio Turnover Rate		12	%		27	%		19	%		26	%		15	%		16	%
Net Assets, End of Period (in thousands)	$	137,226		$	137,037		$	158,431		$	185,569		$	461,413		$	466,803

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

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Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	5.74		$	5.32		$	5.17		$	8.79		$	8.24		$	7.16
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.05			0.10			0.12			0.15			0.15			0.13
Net Realized and    Unrealized Gain (Loss)		0.83			0.43			0.21			(3.28	)		0.65			1.15
Total From    Investment Operations		0.88			0.53			0.33			(3.13	)		0.80			1.28
Distributions
From Net    Investment Income		(0.11	)		(0.11	)		(0.18	)		(0.15	)		(0.14	)		(0.12	)
From Net    Realized Gains		—			—			—			(0.34	)		(0.11	)		(0.08	)
Total Distributions		(0.11	)		(0.11	)		(0.18	)		(0.49	)		(0.25	)		(0.20	)
Net Asset Value, End of Period	$	6.51		$	5.74		$	5.32		$	5.17		$	8.79		$	8.24
Total Return(3)		15.45	%		10.11	%		7.07	%		(37.46	)%		9.88	%		18.24	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.81	%(4)		0.89	%		0.90	%		0.90	%		0.90	%		0.90	%
Ratio of Operating Expenses to Average Net Assets (Before Expense Waiver)		0.91	%(4)		0.91	%		0.90	%		0.90	%		0.90	%		0.90	%
Ratio of Net Investment Income (Loss) to Average Net Assets		1.59	%(4)		1.76	%		2.53	%		2.18	%		1.72	%		1.75	%
Ratio of Net Investment Income (Loss) to Average Net Assets (Before Expense Waiver)		1.49	%(4)		1.74	%		2.53	%		2.18	%		1.72	%		1.75	%
Portfolio Turnover Rate		12	%		27	%		19	%		26	%		15	%		16	%
Net Assets, End of Period (in thousands)	$	3,919		$	3,980		$	8,035		$	12,030		$	28,077		$	31,141

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

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A Class(1)
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(2)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	5.72		$	5.30		$	5.15		$	8.76		$	8.21		$	7.14
Income From Investment Operations
Net Investment    Income (Loss)(3)		0.03			0.07			0.10			0.12			0.11			0.10
Net Realized and    Unrealized Gain (Loss)		0.83			0.44			0.21			(3.28	)		0.65			1.13
Total From    Investment Operations		0.86			0.51			0.31			(3.16	)		0.76			1.23
Distributions
From Net    Investment Income		(0.08	)		(0.09	)		(0.16	)		(0.11	)		(0.10	)		(0.08	)
From Net    Realized Gains		—			—			—			(0.34	)		(0.11	)		(0.08	)
Total Distributions		(0.08	)		(0.09	)		(0.16	)		(0.45	)		(0.21	)		(0.16	)
Net Asset Value, End of Period	$	6.50		$	5.72		$	5.30		$	5.15		$	8.76		$	8.21
Total Return(4)		15.15	%		9.64	%		6.59	%		(37.78	)%		9.40	%		17.62	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.26	%(5)		1.34	%		1.35	%		1.35	%		1.35	%		1.35	%
Ratio of Operating Expenses to Average Net Assets (Before Expense Waiver)		1.36	%(5)		1.36	%		1.35	%		1.35	%		1.35	%		1.35	%
Ratio of Net Investment Income (Loss) to Average Net Assets		1.14	%(5)		1.31	%		2.08	%		1.73	%		1.27	%		1.30	%
Ratio of Net Investment Income (Loss) to Average Net Assets (Before Expense Waiver)		1.04	%(5)		1.29	%		2.08	%		1.73	%		1.27	%		1.30	%
Portfolio Turnover Rate		12	%		27	%		19	%		26	%		15	%		16	%
Net Assets, End of Period (in thousands)	$	4,426		$	4,130		$	4,881		$	7,004		$	16,059		$	16,973

(1) Prior to March 1, 2010, the A Class was referred to as the Advisor Class.

(2) Six months ended April 30, 2011 (unaudited).

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

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Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

22

Notes

23

Notes

24

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71836   1106

SEMIANNUAL REPORT     |     APRIL 30, 2011

Focused Growth Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	10
Statement of Operations	11
Statement of Changes in Net Assets	12
Notes to Financial Statements	13
Financial Highlights	19
Additional Information	25

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	Since Inception	Inception Date
Investor Class	AFSIX	15.25%	17.21%	4.07%	5.34%	2/28/05
Russell 1000 Growth Index	—	16.96%	20.87%	5.06%	5.85%	—
Institutional Class	AFGNX	15.38%	17.46%	—	1.94%	9/28/07
A Class    No sales charge*    With sales charge*	AFGAX	15.19%   8.56%	16.92% 10.20%	— —	1.50% -0.17%	9/28/07
B Class    No sales charge*    With sales charge*	AFGBX	14.63%   9.63%	16.01% 12.01%	— —	0.71% -0.12%	9/28/07
C Class    No sales charge*    With sales charge*	AFGCX	14.73%   13.73%	16.11% 16.11%	— —	0.74% 0.74%	9/28/07
R Class	AFGRX	15.05%	16.66%	—	1.23%	9/28/07

* Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. B Class shares redeemed within six years of purchase are subject to a CDSC that declines from 5.00% during the first year after purchase to 0.00% the sixth year after purchase. C Class shares redeemed within 12 months of purchase are subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class	B Class	C Class	R Class
1.02%	0.82%	1.27%	2.02%	2.02%	1.52%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. International investing involves special risks, such as political instability and currency fluctuations.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011

Top Ten Holdings	% of net assets
Apple, Inc.	4.7%
Schlumberger Ltd.	4.1%
Coca-Cola Co. (The)	3.9%
EMC Corp.	3.6%
Accenture plc, Class A	3.3%
Oracle Corp.	3.1%
Express Scripts, Inc.	2.9%
PPG Industries, Inc.	2.7%
Novo Nordisk A/S B Shares	2.6%
BorgWarner, Inc.	2.6%

Top Five Industries	% of net assets
Computers & Peripherals	9.9%
Software	6.6%
Aerospace & Defense	5.5%
Machinery	5.2%
Pharmaceuticals	4.6%

Types of Investments in Portfolio	% of net assets
Domestic Common Stocks	90.4%
Foreign Common Stocks*	7.6%
Total Common Stocks	98.0%
Temporary Cash Investments	2.1%
Other Assets and Liabilities	(0.1)%

* Includes depositary shares, dual listed securities and foreign ordinary shares.

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 - 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,152.50	$5.39	1.01%
Institutional Class	$1,000	$1,153.80	$4.33	0.81%
A Class	$1,000	$1,151.90	$6.72	1.26%
B Class	$1,000	$1,146.30	$10.70	2.01%
C Class	$1,000	$1,147.30	$10.70	2.01%
R Class	$1,000	$1,150.50	$8.05	1.51%
Hypothetical
Investor Class	$1,000	$1,019.79	$5.06	1.01%
Institutional Class	$1,000	$1,020.78	$4.06	0.81%
A Class	$1,000	$1,018.55	$6.31	1.26%
B Class	$1,000	$1,014.83	$10.04	2.01%
C Class	$1,000	$1,014.83	$10.04	2.01%
R Class	$1,000	$1,017.31	$7.55	1.51%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 98.0%
AEROSPACE & DEFENSE — 5.5%
Honeywell International, Inc.		3,367	$	206,162
Rockwell Collins, Inc.		7,124		449,524
Textron, Inc.		20,480		534,528
				1,190,214
AIR FREIGHT & LOGISTICS — 2.0%
United Parcel Service, Inc., Class B		5,618		421,181
AUTO COMPONENTS — 2.6%
BorgWarner, Inc.(1)		7,366		568,950
AUTOMOBILES — 1.0%
Harley-Davidson, Inc.		6,015		224,119
BEVERAGES — 3.9%
Coca-Cola Co. (The)		12,354		833,401
BIOTECHNOLOGY — 2.3%
Alexion Pharmaceuticals, Inc.(1)		432		41,856
Amgen, Inc.(1)		8,142		462,873
				504,729
CAPITAL MARKETS — 0.4%
BlackRock, Inc.		421		82,491
CHEMICALS — 2.7%
PPG Industries, Inc.		6,106		578,055
COMMUNICATIONS EQUIPMENT — 0.5%
QUALCOMM, Inc.		2,056		116,863
COMPUTERS & PERIPHERALS — 9.9%
Apple, Inc.(1)		2,908		1,012,653
EMC Corp.(1)		27,279		773,087
NetApp, Inc.(1)		6,612		343,691
				2,129,431
CONSUMER FINANCE — 2.0%
American Express Co.		8,749		429,401
DIVERSIFIED — 2.2%
iShares Russell 1000 Growth Index Fund		7,452		465,377
ELECTRICAL EQUIPMENT — 2.6%
Rockwell Automation, Inc.		6,347		553,014
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 1.7%
Jabil Circuit, Inc.		18,199		361,068
ENERGY EQUIPMENT & SERVICES — 4.1%
Schlumberger Ltd.		9,748		874,883
FOOD PRODUCTS — 1.4%
General Mills, Inc.		2,913		112,383
Kellogg Co.		3,392		194,260
				306,643
HEALTH CARE EQUIPMENT & SUPPLIES — 1.7%
Covidien plc		6,436		358,421
HEALTH CARE PROVIDERS & SERVICES — 2.9%
Express Scripts, Inc.(1)		10,809		613,303
HOTELS, RESTAURANTS & LEISURE — 1.9%
Chipotle Mexican Grill, Inc.(1)		259		69,098
Las Vegas Sands Corp.(1)		600		28,206
Starwood Hotels & Resorts Worldwide, Inc.		5,389		321,023
				418,327
HOUSEHOLD DURABLES — 1.5%
Whirlpool Corp.		3,654		314,902
HOUSEHOLD PRODUCTS — 0.9%
Procter & Gamble Co. (The)		3,014		195,609
INSURANCE — 1.4%
Aflac, Inc.		5,520		310,169
INTERNET SOFTWARE & SERVICES — 0.4%
Google, Inc., Class A(1)		162		88,144
IT SERVICES — 3.3%
Accenture plc, Class A		12,295		702,413
MACHINERY — 5.2%
Eaton Corp.		10,548		564,634
Illinois Tool Works, Inc.		9,675		565,117
				1,129,751
MEDIA — 2.1%
Scripps Networks Interactive, Inc., Class A		8,006		411,668
Walt Disney Co. (The)		1,106		47,669
				459,337
METALS & MINING — 3.2%
Cliffs Natural Resources, Inc.		3,514		329,332
Freeport-McMoRan Copper & Gold, Inc.		4,045		222,596
Newmont Mining Corp.		2,180		127,770
				679,698
MULTILINE RETAIL — 2.8%
Kohl’s Corp.		5,317		280,259
Target Corp.		6,655		326,761
				607,020
OIL, GAS & CONSUMABLE FUELS — 4.0%
Cimarex Energy Co.		3,740		413,607
ConocoPhillips		401		31,651
Occidental Petroleum Corp.		3,556		406,415
				851,673
PHARMACEUTICALS — 4.6%
Abbott Laboratories		7,870		409,555
Novo Nordisk A/S B Shares		4,511		570,247
				979,802

8

	Shares		Value
REAL ESTATE MANAGEMENT & DEVELOPMENT — 0.1%
CB Richard Ellis Group, Inc., Class A(1)	1,066	$	28,473
ROAD & RAIL — 1.5%
Union Pacific Corp.	3,190		330,069
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 4.4%
Broadcom Corp., Class A(1)	9,873		347,332
Linear Technology Corp.	14,558		506,618
RF Micro Devices, Inc.(1)	13,110		87,313
			941,263
SOFTWARE — 6.6%
Intuit, Inc.(1)	5,243		291,301
Microsoft Corp.	17,560		456,911
Oracle Corp.	18,751		675,974
			1,424,186
SPECIALTY RETAIL — 4.1%
Home Depot, Inc. (The)	14,768		548,484
Limited Brands, Inc.	5,044		207,611
OfficeMax, Inc.(1)	4,972		49,521
Williams-Sonoma, Inc.	1,606		69,716
			875,332
WIRELESS TELECOMMUNICATION SERVICES — 0.6%
Crown Castle International Corp.(1)	3,250		139,295
TOTAL COMMON STOCKS (Cost $16,287,536)			21,087,007
Temporary Cash Investments — 2.1%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	65,604	$	65,604
Repurchase Agreement, Credit Suisse First Boston, Inc., (collateralized by various U.S. Treasury obligations, 1.375%, 5/15/13, valued at $408,000), in a joint trading account at 0.01%, dated 4/29/11, due 5/2/11 (Delivery value $400,000)			400,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $465,604)			465,604
TOTAL INVESTMENT SECURITIES — 100.1% (Cost $16,753,140)			21,552,611
OTHER ASSETS AND LIABILITIES — (0.1)%			(27,608	)
TOTAL NET ASSETS — 100.0%		$	21,525,003

Forward Foreign Currency Exchange Contracts
Contracts to Sell		Counterparty	Settlement Date	Value	Unrealized Gain (Loss)
1,907,364	DKK for USD	UBS AG	5/31/11	$378,582	$(4,281)

(Value on Settlement Date $374,301)

Notes to Schedule of Investments

DKK = Danish Krone

USD = United States Dollar

(1) Non-income producing.

See Notes to Financial Statements.

9

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $16,753,140)	$	21,552,611
Receivable for capital shares sold		2,312
Dividends and interest receivable		18,621
		21,573,544
Liabilities
Payable for capital shares redeemed		25,697
Unrealized loss on forward foreign currency exchange contracts		4,281
Accrued management fees		17,413
Distribution and service fees payable		1,150
		48,541
Net Assets	$	21,525,003
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	18,604,899
Undistributed net investment income		20,673
Accumulated net realized loss		(1,895,814	)
Net unrealized appreciation		4,795,245
	$	21,525,003

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$17,551,062	1,504,597	$11.66
Institutional Class, $0.01 Par Value	$26,788	2,299	$11.65
A Class, $0.01 Par Value	$3,034,937	260,257	$11.66*
B Class, $0.01 Par Value	$54,529	4,731	$11.53
C Class, $0.01 Par Value	$407,833	35,379	$11.53
R Class, $0.01 Par Value	$449,854	38,638	$11.64

*Maximum offering price $12.37 (net asset value divided by 0.9425)

See Notes to Financial Statements.

10

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $1,269)	$	130,662
Interest		192
		130,854
Expenses:
Management fees		88,966
Distribution and service fees:
A Class		1,951
B Class		263
C Class		1,310
R Class		1,041
Directors’ fees and expenses		490
		94,021
Net investment income (loss)		36,833
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		176,623
Foreign currency transactions		(24,518	)
		152,105
Change in net unrealized appreciation (depreciation) on:
Investments		2,113,277
Translation of assets and liabilities in foreign currencies		(3,702	)
		2,109,575
Net realized and unrealized gain (loss)		2,261,680
Net Increase (Decrease) in Net Assets Resulting from Operations	$	2,298,513

See Notes to Financial Statements.

11

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	36,833		$	47,814
Net realized gain (loss)		152,105			505,068
Change in net unrealized appreciation (depreciation)		2,109,575			1,440,996
Net increase (decrease) in net assets resulting from operations		2,298,513			1,993,878
Distributions to Shareholders
From net investment income:
Investor Class		(72,511	)		(5,153	)
Institutional Class		(180	)		(52	)
A Class		(1,550	)		—
R Class		(89	)		—
Decrease in net assets from distributions		(74,330	)		(5,205	)
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		5,828,338			(1,608,018	)
Net increase (decrease) in net assets		8,052,521			380,655
Net Assets
Beginning of period		13,472,482			13,091,827
End of period	$	21,525,003		$	13,472,482
Undistributed net investment income	$	20,673		$	58,170

See Notes to Financial Statements.

12

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Focused Growth Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by purchasing stocks of larger-sized companies that management believes will increase in value over time.

The fund is authorized to issue the Investor Class, the Institutional Class, the A Class, the B Class, the C Class and the R Class. The A Class may incur an initial sales charge. The A Class, B Class and C Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Forward foreign currency exchange contracts are valued at the mean of the latest bid and asked prices of the forward currency rates as provided by an independent pricing service.

The value of investments initially expressed in foreign currencies is translated into U.S. dollars at prevailing exchange rates.

13

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Foreign Currency Translations — All assets and liabilities initially expressed in foreign currencies are translated into U.S. dollars at prevailing exchange rates at period end. The fund may enter into spot foreign currency exchange contracts to facilitate transactions denominated in a foreign currency. Purchases and sales of investment securities, dividend and interest income, spot foreign currency exchange contracts, and expenses are translated at the rates of exchange prevailing on the respective dates of such transactions. Net realized and unrealized foreign currency exchange gains or losses related to investment securities are a component of net realized gain (loss) on investment transactions and change in net unrealized appreciation (depreciation) on investments, respectively.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Exchange-Traded Funds — The fund may invest in exchange-traded funds (ETFs). ETFs are a type of index fund bought and sold on a securities exchange. An ETF trades like common stock and represents a fixed portfolio of securities designed to track the performance and dividend yield of a particular domestic or foreign market index. A fund may purchase an ETF to temporarily gain exposure to a portion of the U.S. or a foreign market while awaiting purchase of underlying securities. The risks of owning an ETF generally reflect the risks of owning the underlying securities they are designed to track, although a lack of liquidity on an ETF could result in it being more volatile. Additionally, ETFs have fees and expenses that reduce their value.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

14

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The annual management fee schedule ranges from 0.800% to 1.000% for the Investor Class, A Class, B Class, C Class and R Class. The Institutional Class is 0.200% less at each point within the range. The effective annual management fee for each class for the six months ended April 30, 2011 was 1.00% for the Investor Class, A Class, B Class, C Class and R Class and 0.80% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a separate Master Distribution and Individual Shareholder Services Plan for each of the A Class, B Class, C Class and R Class (collectively the plans), pursuant to Rule 12b-1 of the 1940 Act. The plans provide that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The plans provide that the B Class and C Class will each pay ACIS an annual distribution and service fee of 1.00%, of which 0.25% is paid for individual shareholder services and 0.75% is paid for distribution services. The plans provide that the R Class will pay ACIS an annual distribution and service fee of 0.50%. The fees are computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services. Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a securities lending agreement with JPMorgan Chase Bank (JPMCB) and a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMCB is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

15

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $9,378,447 and $3,794,586, respectively.

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		50,000,000						50,000,000
Sold		411,516		$	4,588,838			288,170		$	2,753,240
Issued in reinvestment of distributions		6,447			70,211			526			5,016
Redeemed		(165,970	)		(1,840,059	)		(472,403	)		(4,453,387	)
		251,993			2,818,990			(183,707	)		(1,695,131	)
Institutional Class/Shares Authorized		10,000,000						10,000,000
Issued in reinvestment of distributions		17			180			5			52
A Class/Shares Authorized		10,000,000						10,000,000
Sold		214,943			2,436,072			16,805			159,354
Issued in reinvestment of distributions		141			1,540			—			—
Redeemed		(4,211	)		(47,126	)		(10,141	)		(97,426	)
		210,873			2,390,486			6,664			61,928
B Class/Shares Authorized		10,000,000						10,000,000
Redeemed		(624	)		(6,470	)		(94	)		(854	)
C Class/Shares Authorized		10,000,000						10,000,000
Sold		29,594			335,711			6,726			62,733
Redeemed		(7,275	)		(80,420	)		(4,044	)		(37,545	)
		22,319			255,291			2,682			25,188
R Class/Shares Authorized		10,000,000						10,000,000
Sold		36,303			369,772			98			938
Issued in reinvestment of distributions		8			89			—			—
Redeemed		—			—			(14	)		(139	)
		36,311			369,861			84			799
Net increase (decrease)		520,889		$	5,828,338			(174,366	)	$	(1,608,018	)

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

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The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2			Level 3
Investment Securities
Domestic Common Stocks	$	19,455,926		—			—
Foreign Common Stocks		1,060,834	$	570,247			—
Temporary Cash Investments		65,604		400,000			—
Total Value of Investment Securities	$	20,582,364	$	970,247			—
Other Financial Instruments
Total Unrealized Gain (Loss) on Forward Foreign Currency Exchange Contracts		—	$	(4,281	)		—

7. Derivative Instruments

Foreign Currency Risk — The fund is subject to foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The value of foreign investments held by a fund may be significantly affected by changes in foreign currency exchange rates. The dollar value of a foreign security generally decreases when the value of the dollar rises against the foreign currency in which the security is denominated and tends to increase when the value of the dollar declines against such foreign currency. A fund may enter into forward foreign currency exchange contracts to reduce a fund’s exposure to foreign currency exchange rate fluctuations. The net U.S. dollar value of foreign currency underlying all contractual commitments held by a fund and the resulting unrealized appreciation or depreciation are determined daily. Realized gain or loss is recorded upon the termination of the contract. Net realized and unrealized gains or losses occurring during the holding period of forward foreign currency exchange contracts are a component of net realized gain (loss) on foreign currency transactions and change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies, respectively. A fund bears the risk of an unfavorable change in the foreign currency exchange rate underlying the forward contract. Additionally, losses, up to the fair value, may arise if the counterparties do not perform under the contract terms. The risk of loss from non-performance by the counterparty may be reduced by the use of master netting agreements. The foreign currency risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

The value of foreign currency risk derivative instruments as of April 30, 2011, is disclosed on the Statement of Assets and Liabilities as a liability of $4,281 in unrealized loss on forward foreign currency exchange contracts. For the six months ended April 30, 2011, the effect of foreign currency risk derivative instruments on the Statement of Operations was $(24,571) in net realized gain (loss) on foreign currency transactions and $(3,637) in change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies.

8. Risk Factors

There are certain risks involved in investing in foreign securities. These risks include those  resulting from future adverse political, social, and economic developments, fluctuations in currency exchange rates, the possible imposition of exchange controls, and other foreign laws or restrictions.

17

9. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	16,851,728
Gross tax appreciation of investments	$	4,796,543
Gross tax depreciation of investments		(95,660	)
Net tax appreciation (depreciation) of investments	$	4,700,883

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(1,956,380), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers of $(218,461) and $(1,737,919) expire in 2016 and 2017, respectively.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies.  The changes are generally effective for taxable years beginning after the date of enactment.  Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period.  However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date.  As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

18

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	10.17		$	8.73		$	7.73		$	12.92		$	11.42		$	10.53
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.03			0.04			0.04			0.02			0.04			0.01
Net Realized and    Unrealized Gain (Loss)		1.52			1.40			1.01			(3.74	)		1.73			0.95
Total From    Investment Operations		1.55			1.44			1.05			(3.72	)		1.77			0.96
Distributions
From Net    Investment Income		(0.06	)		—	(3)		(0.05	)		(0.01	)		(0.04	)		—	(3)
From Net Realized Gains		—			—			—			(1.46	)		(0.23	)		(0.07	)
Total Distributions		(0.06	)		—	(3)		(0.05	)		(1.47	)		(0.27	)		(0.07	)
Net Asset Value, End of Period	$	11.66		$	10.17		$	8.73		$	7.73		$	12.92		$	11.42
Total Return(4)		15.25	%		16.54	%		13.77	%		(32.19	)%		15.78	%		9.13	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.01	%(5)		1.02	%		1.00	%		1.00	%		1.00	%		1.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.46	%(5)		0.38	%		0.50	%		0.22	%		0.33	%		0.07	%
Portfolio Turnover Rate		22	%		66	%		125	%		130	%		275	%		313	%
Net Assets, End of Period (in thousands)	$	17,551		$	12,739		$	12,541		$	8,814		$	13,381		$	15,837

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Per-share amount was less than $0.005.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

19

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	10.17		$	8.73		$	7.73		$	12.93		$	12.59
Income From Investment Operations
Net Investment Income (Loss)(3)		0.04			0.05			0.05			0.04			—	(4)
Net Realized and Unrealized Gain (Loss)		1.52			1.41			1.01			(3.75	)		0.34
Total From Investment Operations		1.56			1.46			1.06			(3.71	)		0.34
Distributions
From Net Investment Income		(0.08	)		(0.02	)		(0.06	)		(0.03	)		—
From Net Realized Gains		—			—			—			(1.46	)		—
Total Distributions		(0.08	)		(0.02	)		(0.06	)		(1.49	)		—
Net Asset Value, End of Period	$	11.65		$	10.17		$	8.73		$	7.73		$	12.93
Total Return(5)		15.38	%		16.77	%		14.00	%		(32.09	)%		2.70	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.81	%(6)		0.82	%		0.80	%		0.80	%		0.80	%(6)
Ratio of Net Investment Income (Loss) to Average Net Assets		0.66	%(6)		0.58	%		0.70	%		0.42	%		(0.40	)%(6)
Portfolio Turnover Rate		22	%		66	%		125	%		130	%		275	%(7)
Net Assets, End of Period (in thousands)	$	27		$	23		$	20		$	17		$	26

(1) Six months ended April 30, 2011 (unaudited).

(2) September 28, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Per-share amount was less than $0.005.

(5) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(6) Annualized.

(7) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

20

A Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	10.15		$	8.74		$	7.73		$	12.92		$	12.59
Income From Investment Operations
Net Investment Income (Loss)(3)		0.01			0.01			0.02			—	(4)		(0.01	)
Net Realized and Unrealized Gain (Loss)		1.53			1.40			1.02			(3.75	)		0.34
Total From Investment Operations		1.54			1.41			1.04			(3.75	)		0.33
Distributions
From Net Investment Income		(0.03	)		—			(0.03	)		—			—
From Net Realized Gains		—			—			—			(1.44	)		—
Total Distributions		(0.03	)		—			(0.03	)		(1.44	)		—
Net Asset Value, End of Period	$	11.66		$	10.15		$	8.74		$	7.73		$	12.92
Total Return(5)		15.19	%		16.27	%		13.48	%		(32.37	)%		2.62	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.26	%(6)		1.27	%		1.25	%		1.25	%		1.25	%(6)
Ratio of Net Investment Income (Loss) to Average Net Assets		0.21	%(6)		0.13	%		0.25	%		(0.03	)%		(0.85	)%(6)
Portfolio Turnover Rate		22	%		66	%		125	%		130	%		275	%(7)
Net Assets, End of Period (in thousands)	$	3,035		$	501		$	373		$	241		$	26

(1) Six months ended April 30, 2011 (unaudited).

(2) September 28, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Per-share amount was less than $0.005.

(5) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(6) Annualized.

(7) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

21

B Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	10.05		$	8.71		$	7.73		$	12.91		$	12.59
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.03	)		(0.06	)		(0.04	)		(0.08	)		(0.02	)
Net Realized and Unrealized Gain (Loss)		1.51			1.40			1.02			(3.75	)		0.34
Total From Investment Operations		1.48			1.34			0.98			(3.83	)		0.32
Distributions
From Net Realized Gains		—			—			—			(1.35	)		—
Net Asset Value, End of Period	$	11.53		$	10.05		$	8.71		$	7.73		$	12.91
Total Return(4)		14.63	%		15.38	%		12.68	%		(32.87	)%		2.54	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.01	%(5)		2.02	%		2.00	%		2.00	%		2.00	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.54	)%(5)		(0.62	)%		(0.50	)%		(0.78	)%		(1.60	)%(5)
Portfolio Turnover Rate		22	%		66	%		125	%		130	%		275	%(6)
Net Assets, End of Period (in thousands)	$	55		$	54		$	47		$	30		$	26

(1) Six months ended April 30, 2011 (unaudited).

(2) September 28, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

22

C Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	10.05		$	8.71		$	7.73		$	12.91		$	12.59
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.03	)		(0.06	)		(0.04	)		(0.08	)		(0.02	)
Net Realized and Unrealized Gain (Loss)		1.51			1.40			1.02			(3.75	)		0.34
Total From Investment Operations		1.48			1.34			0.98			(3.83	)		0.32
Distributions
From Net Realized Gains		—			—			—			(1.35	)		—
Net Asset Value, End of Period	$	11.53		$	10.05		$	8.71		$	7.73		$	12.91
Total Return(4)		14.73	%		15.38	%		12.68	%		(32.87	)%		2.54	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.01	%(5)		2.02	%		2.00	%		2.00	%		2.00	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.54	)%(5)		(0.62	)%		(0.50	)%		(0.78	)%		(1.52	)%(5)
Portfolio Turnover Rate		22	%		66	%		125	%		130	%		275	%(6)
Net Assets, End of Period (in thousands)	$	408		$	131		$	90		$	73		$	76

(1) Six months ended April 30, 2011 (unaudited).

(2) September 28, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

23

R Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	10.12		$	8.73		$	7.73		$	12.92		$	12.59
Income From Investment Operations
Net Investment Income (Loss)(3)		—	(4)		(0.01	)		—	(4)		(0.02	)		(0.01	)
Net Realized and Unrealized Gain (Loss)		1.52			1.40			1.02			(3.76	)		0.34
Total From Investment Operations		1.52			1.39			1.02			(3.78	)		0.33
Distributions
From Net Investment Income		—	(4)		—			(0.02	)		—			—
From Net Realized Gains		—			—			—			(1.41	)		—
Total Distributions		—	(4)		—			(0.02	)		(1.41	)		—
Net Asset Value, End of Period	$	11.64		$	10.12		$	8.73		$	7.73		$	12.92
Total Return(5)		15.05	%		15.92	%		13.19	%		(32.56	)%		2.62	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.51	%(6)		1.52	%		1.50	%		1.50	%		1.50	%(6)
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.04	)%(6)		(0.12	)%		0.00	%(7)		(0.28	)%		(1.10	)%(6)
Portfolio Turnover Rate		22	%		66	%		125	%		130	%		275	%(8)
Net Assets, End of Period (in thousands)	$	450		$	24		$	20		$	17		$	26

(1) Six months ended April 30, 2011 (unaudited).

(2) September 28, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Per-share amount was less than $0.005.

(5) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(6) Annualized.

(7) Ratio was less than 0.005%.

(8) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

24

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

25

Notes

26

Notes

27

Notes

28

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71835   1106

SEMIANNUAL REPORT     |      APRIL 30, 2011

Fundamental Equity Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	12
Statement of Operations	13
Statement of Changes in Net Assets	14
Notes to Financial Statements	15
Financial Highlights	21
Additional Information	27

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	Since Inception	Inception Date
A Class    No sales charge*    With sales charge*	AFDAX	17.33% 10.56%	17.52% 10.73%	4.59% 3.36%	7.06% 6.07%	11/30/04
S&P 500 Index	—	16.36%	17.22%	2.95%	4.48%	—
Investor Class	AFDIX	17.42%	17.82%	4.84%	6.58%	7/29/05
Institutional Class	AFEIX	17.64%	18.04%	5.06%	6.79%	7/29/05
B Class    No sales charge*    With sales charge*	AFDBX	16.84% 11.84%	16.54% 12.54%	3.79% 3.61%	6.23% 6.23%	11/30/04
C Class    No sales charge*    With sales charge*	AFDCX	16.93% 15.93%	16.63% 16.63%	3.80% 3.80%	6.24% 6.24%	11/30/04
R Class	AFDRX	17.17%	17.17%	4.32%	6.04%	7/29/05

* Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. B Class shares redeemed within six years of purchase are subject to a CDSC that declines from 5.00% during the first year after purchase to 0.00% the sixth year after purchase. C Class shares redeemed within 12 months of purchase are subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class	B Class	C Class	R Class
1.02%	0.82%	1.27%	2.02%	2.02%	1.52%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com.

Unless otherwise indicated, performance reflects A Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011

Top Ten Holdings	% of net assets
Exxon Mobil Corp.	4.5%
Apple, Inc.	3.3%
International Business Machines Corp.	3.1%
Wells Fargo & Co.	2.2%
Chevron Corp.	2.2%
Procter & Gamble Co. (The)	2.0%
JPMorgan Chase & Co.	2.0%
Microsoft Corp.	2.0%
EMC Corp.	1.9%
Honeywell International, Inc.	1.7%

Top Five Industries	% of net assets
Oil, Gas & Consumable Fuels	11.7%
Computers & Peripherals	6.1%
Insurance	5.6%
Health Care Providers & Services	4.7%
Pharmaceuticals	4.7%

Types of Investments in Portfolio	% of net assets
Common Stocks and Futures	98.9%
Temporary Cash Investments	1.0%
Other Assets and Liabilities	0.1%

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 - 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,174.20	$5.44	1.01%
Institutional Class	$1,000	$1,176.40	$4.37	0.81%
A Class	$1,000	$1,173.30	$6.79	1.26%
B Class	$1,000	$1,168.40	$10.81	2.01%
C Class	$1,000	$1,169.30	$10.81	2.01%
R Class	$1,000	$1,171.70	$8.13	1.51%
Hypothetical
Investor Class	$1,000	$1,019.79	$5.06	1.01%
Institutional Class	$1,000	$1,020.78	$4.06	0.81%
A Class	$1,000	$1,018.55	$6.31	1.26%
B Class	$1,000	$1,014.83	$10.04	2.01%
C Class	$1,000	$1,014.83	$10.04	2.01%
R Class	$1,000	$1,017.31	$7.55	1.51%

* Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 98.5%
AEROSPACE & DEFENSE — 3.1%
General Dynamics Corp.		21,959	$	1,599,054
Honeywell International, Inc.		57,302		3,508,602
United Technologies Corp.		14,266		1,277,948
				6,385,604
AIR FREIGHT & LOGISTICS — 0.8%
United Parcel Service, Inc., Class B		22,279		1,670,257
AIRLINES — 0.2%
Allegiant Travel Co.		5,209		233,728
United Continental Holdings, Inc.(1)		1,558		35,554
US Airways Group, Inc.(1)		5,581		50,731
				320,013
AUTO COMPONENTS — 0.1%
American Axle & Manufacturing Holdings, Inc.(1)		9,927		127,066
AUTOMOBILES — 0.9%
Ford Motor Co.(1)		116,979		1,809,665
BEVERAGES — 0.7%
Dr Pepper Snapple Group, Inc.		38,159		1,495,833
BIOTECHNOLOGY — 1.7%
Amgen, Inc.(1)		57,543		3,271,320
Gilead Sciences, Inc.(1)		4,328		168,099
				3,439,419
CAPITAL MARKETS — 0.5%
Ameriprise Financial, Inc.		4,487		278,463
Legg Mason, Inc.		22,189		824,322
				1,102,785
CHEMICALS — 1.2%
Ashland, Inc.		6,894		427,979
E.I. du Pont de Nemours & Co.		8,735		496,061
Eastman Chemical Co.		1,202		128,914
International Flavors & Fragrances, Inc.		22,680		1,440,634
				2,493,588
COMMERCIAL BANKS — 3.2%
Bank of Hawaii Corp.		13,143		641,247
PNC Financial Services Group, Inc.		19,750		1,231,215
Wells Fargo & Co.		156,377		4,552,134
				6,424,596
COMMERCIAL SERVICES & SUPPLIES — 0.2%
Knoll, Inc.		23,562		462,522
COMMUNICATIONS EQUIPMENT — 1.1%
Cisco Systems, Inc.		57,029		1,001,429
Motorola Mobility Holdings, Inc.(1)		3,560		92,774
Motorola Solutions, Inc.(1)		4,068		186,640
QUALCOMM, Inc.		15,148		861,012
				2,141,855
COMPUTERS & PERIPHERALS — 6.1%
Apple, Inc.(1)		19,315		6,726,062
EMC Corp.(1)		138,570		3,927,074
Hewlett-Packard Co.		14,907		601,796
SanDisk Corp.(1)		21,460		1,054,544
				12,309,476
CONSTRUCTION & ENGINEERING — 0.2%
EMCOR Group, Inc.(1)		9,938		307,780
Foster Wheeler AG(1)		2,003		71,247
				379,027
CONSUMER FINANCE — 0.6%
American Express Co.		23,082		1,132,865
CONTAINERS & PACKAGING — 0.2%
Sealed Air Corp.		13,063		336,634
DIVERSIFIED CONSUMER SERVICES — 0.3%
Sotheby’s		10,475		529,197
DIVERSIFIED FINANCIAL SERVICES — 3.7%
Citigroup, Inc.(1)		725,703		3,330,977
JPMorgan Chase & Co.		90,612		4,134,626
NYSE Euronext		3,045		121,952
				7,587,555
DIVERSIFIED TELECOMMUNICATION SERVICES — 2.0%
AT&T, Inc.		98,576		3,067,685
CenturyLink, Inc.		7,321		298,551
Frontier Communications Corp.		3,875		32,046
Verizon Communications, Inc.		19,303		729,267
				4,127,549
ELECTRIC UTILITIES — 0.5%
FirstEnergy Corp.		23,802		951,128
ELECTRICAL EQUIPMENT — 1.4%
Belden, Inc.		12,262		466,324
Emerson Electric Co.		39,270		2,386,045
				2,852,369

8

	Shares		Value
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS(2)
Power-One, Inc.(1)	6,997	$	57,795
ENERGY EQUIPMENT & SERVICES — 2.1%
Ensco plc ADR	5,289		315,330
Nabors Industries Ltd.(1)	43,920		1,345,709
National Oilwell Varco, Inc.	14,801		1,135,089
Patterson-UTI Energy, Inc.	44,159		1,373,786
Rowan Cos., Inc.(1)	3,946		164,548
			4,334,462
FOOD & STAPLES RETAILING — 1.9%
Safeway, Inc.	13,304		323,420
SYSCO Corp.	9,858		284,995
Walgreen Co.	18,834		804,588
Wal-Mart Stores, Inc.	44,673		2,456,122
			3,869,125
FOOD PRODUCTS — 2.9%
Archer-Daniels-Midland Co.	12,084		447,350
ConAgra Foods, Inc.	7,234		176,871
H.J. Heinz Co.	43,998		2,254,017
Kraft Foods, Inc., Class A	8,722		292,885
Sara Lee Corp.	10,274		197,261
Smithfield Foods, Inc.(1)	33,522		789,778
Tyson Foods, Inc., Class A	85,723		1,705,888
			5,864,050
GAS UTILITIES — 0.1%
Questar Corp.	11,148		195,870
HEALTH CARE EQUIPMENT & SUPPLIES — 0.3%
Covidien plc	1,683		93,726
Medtronic, Inc.	5,050		210,838
Stryker Corp.	6,241		368,219
			672,783
HEALTH CARE PROVIDERS & SERVICES — 4.7%
Aetna, Inc.	24,283		1,004,831
AmerisourceBergen Corp.	61,897		2,515,494
Cardinal Health, Inc.	50,056		2,186,947
Humana, Inc.(1)	13,952		1,062,026
Medco Health Solutions, Inc.(1)	7,204		427,413
UnitedHealth Group, Inc.	47,188		2,323,065
			9,519,776
HOTELS, RESTAURANTS & LEISURE — 0.9%
Bally Technologies, Inc.(1)	4,648		181,226
Cheesecake Factory, Inc. (The)(1)	3,445		101,352
Starbucks Corp.	24,732		895,051
Wyndham Worldwide Corp.	21,894		757,751
			1,935,380
HOUSEHOLD DURABLES — 0.4%
Tupperware Brands Corp.	4,723		300,713
Whirlpool Corp.	5,792		499,155
			799,868
HOUSEHOLD PRODUCTS — 2.3%
Kimberly-Clark Corp.	7,855		518,901
Procter & Gamble Co. (The)	64,116		4,161,129
			4,680,030
INDUSTRIAL CONGLOMERATES — 1.7%
General Electric Co.	164,616		3,366,397
INSURANCE — 5.6%
ACE Ltd.	12,584		846,274
Aflac, Inc.	13,171		740,078
American Financial Group, Inc.	6,410		229,286
Assurant, Inc.	12,663		502,721
Chubb Corp. (The)	7,614		496,357
Principal Financial Group, Inc.	19,505		658,294
Prudential Financial, Inc.	53,458		3,390,306
Travelers Cos., Inc. (The)	39,752		2,515,506
Unum Group	74,212		1,965,134
			11,343,956
INTERNET SOFTWARE & SERVICES — 1.4%
AOL, Inc.(1)	5,450		111,071
eBay, Inc.(1)	7,855		270,212
Google, Inc., Class A(1)	4,399		2,393,496
			2,774,779
IT SERVICES — 4.4%
Accenture plc, Class A	21,719		1,240,806
International Business Machines Corp.	36,369		6,203,824
Western Union Co. (The)	73,900		1,570,375
			9,015,005
LEISURE EQUIPMENT & PRODUCTS — 0.4%
Hasbro, Inc.	16,751		784,617
LIFE SCIENCES TOOLS & SERVICES — 0.1%
Thermo Fisher Scientific, Inc.(1)	3,286		197,127
MACHINERY — 2.5%
Caterpillar, Inc.	4,610		532,040
Deere & Co.	11,747		1,145,332
Dover Corp.	35,745		2,432,090
Oshkosh Corp.(1)	14,826		469,391
Wabtec Corp.	6,010		428,994
			5,007,847

9

Shares Value

MEDIA — 3.7%
CBS Corp., Class B	6,426	$	162,064
Comcast Corp., Class A	112,041		2,939,956
DirecTV, Class A(1)	2,058		99,998
Gannett Co., Inc.	5,733		86,339
Omnicom Group, Inc.	5,968		293,566
Time Warner Cable, Inc.	15,148		1,183,513
Time Warner, Inc.	60,109		2,275,727
Valassis Communications, Inc.(1)	3,075		88,652
Viacom, Inc., Class B	8,416		430,562
			7,560,377
METALS & MINING — 1.5%
Freeport-McMoRan Copper & Gold, Inc.	48,769		2,683,758
Reliance Steel & Aluminum Co.	4,968		281,239
			2,964,997
MULTILINE RETAIL(2)
Big Lots, Inc.(1)	1,382		56,814
MULTI-UTILITIES — 2.8%
CenterPoint Energy, Inc.	69,805		1,298,373
DTE Energy Co.	19,923		1,006,709
NSTAR	36,304		1,680,875
Public Service Enterprise Group, Inc.	2,643		85,026
Xcel Energy, Inc.	65,316		1,589,138
			5,660,121
OIL, GAS & CONSUMABLE FUELS — 11.7%
Anadarko Petroleum Corp.	4,980		393,121
Chevron Corp.	41,006		4,487,697
ConocoPhillips	44,123		3,482,628
Exxon Mobil Corp.	103,220		9,083,360
Hess Corp.	7,149		614,528
Murphy Oil Corp.	10,498		813,385
Occidental Petroleum Corp.	24,283		2,775,304
Peabody Energy Corp.	12,342		824,693
Sunoco, Inc.	19,517		832,595
Valero Energy Corp.	9,697		274,425
Williams Cos., Inc. (The)	8,977		297,767
			23,879,503
PAPER & FOREST PRODUCTS — 0.8%
International Paper Co.	51,340		1,585,379
PHARMACEUTICALS — 4.7%
Abbott Laboratories	52,976		2,756,871
Bristol-Myers Squibb Co.	88,919		2,498,624
Hospira, Inc.(1)	14,290		810,672
Johnson & Johnson	50,570		3,323,460
Merck & Co., Inc.	3,565		128,162
			9,517,789
REAL ESTATE INVESTMENT TRUSTS (REITs) — 0.8%
Annaly Capital Management, Inc.	46,919		837,035
Public Storage	7,453		874,311
			1,711,346
ROAD & RAIL — 1.1%
Avis Budget Group, Inc.(1)	1,514		28,705
Ryder System, Inc.	20,276		1,084,766
Union Pacific Corp.	11,301		1,169,315
			2,282,786
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 2.7%
Altera Corp.	38,388		1,869,496
Intel Corp.	72,890		1,690,319
Marvell Technology Group Ltd.(1)	55,298		853,248
Micron Technology, Inc.(1)	25,931		292,761
Texas Instruments, Inc.	23,642		840,000
			5,545,824
SOFTWARE — 3.1%
Microsoft Corp.	152,734		3,974,139
Oracle Corp.	35,066		1,264,129
Red Hat, Inc.(1)	5,843		277,367
Symantec Corp.(1)	43,998		864,561
			6,380,196
SPECIALTY RETAIL — 2.0%
Gap, Inc. (The)	77,098		1,791,757
Home Depot, Inc. (The)	24,283		901,871
Lowe’s Cos., Inc.	21,800		572,250
Pier 1 Imports, Inc.(1)	64,915		790,665
			4,056,543
TEXTILES, APPAREL & LUXURY GOODS — 0.3%
Coach, Inc.	9,377		560,838
TOBACCO — 1.6%
Altria Group, Inc.	34,395		923,162
Lorillard, Inc.	2,226		237,069
Philip Morris International, Inc.	30,216		2,098,199
			3,258,430
TRADING COMPANIES & DISTRIBUTORS — 0.6%
United Rentals, Inc.(1)	38,315		1,127,227
WIRELESS TELECOMMUNICATION SERVICES — 0.7%
American Tower Corp., Class A(1)	28,370		1,484,035
TOTAL COMMON STOCKS (Cost $142,823,979)			200,130,075

10

Shares Value

Temporary Cash Investments — 1.0%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	5,407	$	5,407
Repurchase Agreement, Credit Suisse First Boston, Inc., (collateralized by various U.S. Treasury obligations, 1.375%, 5/15/13, valued at $2,056,321), in a joint trading account at 0.01%, dated 4/29/11, due 5/2/11 (Delivery value $2,016,002)			2,016,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $2,021,407)			2,021,407

	Value
Temporary Cash Investments — Segregated For Futures Contracts — 0.4%
Repurchase Agreement, Credit Suisse First Boston, Inc., (collateralized by various U.S. Treasury obligations, 1.375%, 5/15/13, valued at $901,680), in a joint trading account at 0.01%, dated 4/29/11, due 5/2/11 (Delivery value $884,001) (Cost $884,000)	$	884,000
TOTAL INVESTMENT SECURITIES — 99.9% (Cost $145,729,386)		203,035,482
OTHER ASSETS AND LIABILITIES — 0.1%		160,999
TOTAL NET ASSETS — 100.0%	$	203,196,481

Futures Contracts
Contracts Purchased		Expiration Date	Underlying Face Amount at Value	Unrealized Gain (Loss)
13	S&P 500 E-Mini Futures	June 2011	$883,805	$43,621

Notes to Schedule of Investments

ADR = American Depositary Receipt

(1) Non-income producing.

(2) Category is less than 0.05% of total net assets.

See Notes to Financial Statements.

11

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $145,729,386)	$	203,035,482
Cash		22,653
Deposits with broker for futures contracts		76,500
Receivable for capital shares sold		303,759
Receivable for variation margin on futures contracts		3,509
Dividends and interest receivable		226,621
		203,668,524
Liabilities
Payable for capital shares redeemed		264,492
Accrued management fees		164,077
Distribution and service fees payable		43,474
		472,043
Net Assets	$	203,196,481
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	266,333,532
Undistributed net investment income		260,385
Accumulated net realized loss		(120,747,153	)
Net unrealized appreciation		57,349,717
	$	203,196,481

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$50,419,840	3,631,972	$13.88
Institutional Class, $0.01 Par Value	$148,875	10,719	$13.89
A Class, $0.01 Par Value	$129,580,744	9,338,582	$13.88*
B Class, $0.01 Par Value	$4,053,669	294,906	$13.75
C Class, $0.01 Par Value	$15,953,710	1,160,245	$13.75
R Class, $0.01 Par Value	$3,039,643	219,520	$13.85

*Maximum offering price $14.73 (net asset value divided by 0.9425)

See Notes to Financial Statements.

12

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends	$	2,009,509
Interest		2,245
		2,011,754
Expenses:
Management fees		985,450
Distribution and service fees:
A Class		161,387
B Class		19,599
C Class		76,000
R Class		7,093
Directors’ fees and expenses		8,983
		1,258,512
Net investment income (loss)		753,242
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		4,921,958
Futures contract transactions		536,844
		5,458,802
Change in net unrealized appreciation (depreciation) on:
Investments		25,330,171
Futures contracts		31,489
		25,361,660
Net realized and unrealized gain (loss)		30,820,462
Net Increase (Decrease) in Net Assets Resulting from Operations	$	31,573,704

See Notes to Financial Statements.

13

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	753,242		$	1,642,996
Net realized gain (loss)		5,458,802			4,940,106
Change in net unrealized appreciation (depreciation)		25,361,660			21,008,718
Net increase (decrease) in net assets resulting from operations		31,573,704			27,591,820
Distributions to Shareholders
From net investment income:
Investor Class		(476,248	)		(497,306	)
Institutional Class		(1,525	)		(3,938	)
A Class		(1,090,905	)		(1,609,202	)
B Class		(3,497	)		(10,268	)
C Class		(13,721	)		(38,972	)
R Class		(16,038	)		(20,874	)
Decrease in net assets from distributions		(1,601,934	)		(2,180,560	)
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		(19,830,544	)		(52,512,098	)
Net increase (decrease) in net assets		10,141,226			(27,100,838	)
Net Assets
Beginning of period		193,055,255			220,156,093
End of period	$	203,196,481		$	193,055,255
Undistributed net investment income	$	260,385		$	1,109,077

See Notes to Financial Statements.

14

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Fundamental Equity Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. Income is a secondary objective. The fund pursues its objectives using a quantitative model that combines fundamental measures of a stock’s value and growth potential. The fund generally invests in larger-sized companies, although it may invest in companies of any size.

The fund is authorized to issue the Investor Class, the Institutional Class, the A Class, the B Class, the C Class and the R Class. The A Class may incur an initial sales charge. The A Class, B Class and C Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Exchange-traded futures contracts are valued at the settlement price as provided by the appropriate clearing corporation.

15

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. Additionally, non-U.S. tax returns filed by the fund due to investments in certain foreign securities remain subject to examination by the relevant taxing authority for seven years from the date of the filing. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

16

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The annual management fee schedule ranges from 0.800% to 1.000% for the Investor Class, A Class, B Class, C Class and R Class. The Institutional Class is 0.200% less at each point within the range. The effective annual management fee for each class for the six months ended April 30, 2011 was 1.00% for the Investor Class, A Class, B Class, C Class and R Class and 0.80% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a separate Master Distribution and Individual Shareholder Services Plan for each of the A Class, B Class, C Class and R Class (collectively the plans), pursuant to Rule 12b-1 of the 1940 Act. The plans provide that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The plans provide that the B Class and C Class will each pay ACIS an annual distribution and service fee of 1.00%, of which 0.25% is paid for individual shareholder services and 0.75% is paid for distribution services. The plans provide that the R Class will pay ACIS an annual distribution and service fee of 0.50%. The fees are computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services. Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a securities lending agreement with JPMorgan Chase Bank (JPMCB) and a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMCB is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

17

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $16,304,348 and $32,756,976, respectively.

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		200,000,000						200,000,000
Sold		543,972		$	7,097,587			795,645		$	9,031,346
Issued in reinvestment of distributions		36,152			451,179			41,430			466,086
Redeemed		(438,867	)		(5,682,065	)		(932,491	)		(10,516,363	)
		141,257			1,866,701			(95,416	)		(1,018,931	)
Institutional Class/Shares Authorized		25,000,000						25,000,000
Sold		1,162			15,636			—			—
Issued in reinvestment of distributions		122			1,525			261			2,933
Redeemed		(563	)		(6,927	)		(16,120	)		(182,316	)
		721			10,234			(15,859	)		(179,383	)
A Class/Shares Authorized		150,000,000						150,000,000
Sold		541,740			7,009,689			1,427,524			16,144,781
Issued in reinvestment of distributions		84,114			1,049,738			138,149			1,555,561
Redeemed		(2,183,793	)		(28,101,505	)		(5,821,242	)		(65,672,758	)
		(1,557,939	)		(20,042,078	)		(4,255,569	)		(47,972,416	)
B Class/Shares Authorized		25,000,000						25,000,000
Sold		1,459			18,654			1,365			15,388
Issued in reinvestment of distributions		262			3,246			787			8,796
Redeemed		(32,883	)		(417,685	)		(64,186	)		(716,061	)
		(31,162	)		(395,785	)		(62,034	)		(691,877	)
C Class/Shares Authorized		50,000,000						50,000,000
Sold		122,809			1,571,127			296,361			3,339,002
Issued in reinvestment of distributions		729			9,037			2,442			27,326
Redeemed		(221,617	)		(2,832,730	)		(509,599	)		(5,682,924	)
		(98,079	)		(1,252,566	)		(210,796	)		(2,316,596	)
R Class/Shares Authorized		10,000,000						10,000,000
Sold		17,269			221,292			61,556			693,221
Issued in reinvestment of distributions		1,286			16,038			1,856			20,874
Redeemed		(19,764	)		(254,380	)		(94,557	)		(1,046,990	)
		(1,209	)		(17,050	)		(31,145	)		(332,895	)
Net increase (decrease)		(1,546,411	)	$	(19,830,544	)		(4,670,819	)	$	(52,512,098	)

18

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2		Level 3
Investment Securities
Common Stocks	$	200,130,075		—		—
Temporary Cash Investments		5,407	$	2,900,000		—
Total Value of Investment Securities	$	200,135,482	$	2,900,000		—
Other Financial Instruments
Total Unrealized Gain (Loss) on Futures Contracts	$	43,621		—		—

7. Derivative Instruments

Equity Price Risk —The fund is subject to equity price risk in the normal course of pursuing its investment objectives. A fund may enter into futures contracts based on an equity index in order to manage its exposure to changes in market conditions. A fund may purchase futures contracts to gain exposure to increases in market value or sell futures contracts to protect against a decline in market value. Upon entering into a futures contract, a fund is required to deposit either cash or securities in an amount equal to a certain percentage of the contract value (initial margin). Subsequent payments (variation margin) are made or received daily, in cash, by a fund. The variation margin is equal to the daily change in the contract value and is recorded as unrealized gains and losses. A fund recognizes a realized gain or loss when the contract is closed or expires. Net realized and unrealized gains or losses occurring during the holding period of futures contracts are a component of net realized gain (loss) on futures contract transactions and change in net unrealized appreciation (depreciation) on futures contracts, respectively. One of the risks of entering into futures contracts is the possibility that the change in value of the contract may not correlate with the changes in value of the underlying securities. The fund frequently utilized equity price risk derivative instruments throughout the reporting period, though the amounts held at period end as disclosed on the Schedule of Investments were lower than the fund’s typical volume during the period.

The value of equity price risk derivative instruments as of April 30, 2011, is disclosed on the Statement of Assets and Liabilities as an asset of $3,509 in receivable for variation margin on futures contracts. For the six months ended April 30, 2011, the effect of equity price risk derivative instruments on the Statement of Operations was $536,844 in net realized gain (loss) on futures contract transactions and $31,489 in change in net unrealized appreciation (depreciation) on futures contracts.

19

8. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	149,496,851
Gross tax appreciation of investments	$	55,245,821
Gross tax depreciation of investments		(1,707,190	)
Net tax appreciation (depreciation) of investments	$	53,538,631

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(122,432,287), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers of $(48,801,060) and $(73,631,227) expire in 2016 and 2017, respectively.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

20

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	11.95		$	10.57		$	9.93		$	15.68		$	12.88		$	11.04
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.07			0.12			0.12			0.15			0.14			0.08
Net Realized and    Unrealized Gain (Loss)		2.00			1.40			0.66			(5.42	)		2.93			2.12
Total From    Investment Operations		2.07			1.52			0.78			(5.27	)		3.07			2.20
Distributions
From Net    Investment Income		(0.14	)		(0.14	)		(0.14	)		(0.12	)		(0.08	)		—
From Net Realized Gains		—			—			—			(0.36	)		(0.19	)		(0.36	)
Total Distributions		(0.14	)		(0.14	)		(0.14	)		(0.48	)		(0.27	)		(0.36	)
Net Asset Value, End of Period	$	13.88		$	11.95		$	10.57		$	9.93		$	15.68		$	12.88
Total Return(3)		17.42	%		14.47	%		8.16	%		(34.56	)%		24.18	%		20.37	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.01	%(4)		1.02	%		1.01	%		1.01	%		1.00	%		1.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		1.03	%(4)		1.06	%		1.37	%		1.15	%		0.99	%		0.74	%
Portfolio Turnover Rate		8	%		29	%		64	%		97	%		82	%		174	%
Net Assets, End of Period (in thousands)	$	50,420		$	41,698		$	37,918		$	37,535		$	53,908		$	3,836

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

21

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	11.96		$	10.59		$	9.94		$	15.70		$	12.90		$	11.05
Income From    Investment Operations
Net Investment    Income (Loss)(2)		0.08			0.15			0.16			0.19			0.19			0.12
Net Realized and    Unrealized Gain (Loss)		2.01			1.38			0.65			(5.44	)		2.91			2.10
Total From    Investment Operations		2.09			1.53			0.81			(5.25	)		3.10			2.22
Distributions
From Net    Investment Income		(0.16	)		(0.16	)		(0.16	)		(0.15	)		(0.11	)		—
From Net Realized Gains		—			—			—			(0.36	)		(0.19	)		(0.37	)
Total Distributions		(0.16	)		(0.16	)		(0.16	)		(0.51	)		(0.30	)		(0.37	)
Net Asset Value, End of Period	$	13.89		$	11.96		$	10.59		$	9.94		$	15.70		$	12.90
Total Return(3)		17.64	%		14.57	%		8.47	%		(34.45	)%		24.43	%		20.51	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.81	%(4)		0.82	%		0.81	%		0.81	%		0.80	%		0.80	%
Ratio of Net Investment Income (Loss) to Average Net Assets		1.23	%(4)		1.26	%		1.57	%		1.35	%		1.19	%		0.94	%
Portfolio Turnover Rate		8	%		29	%		64	%		97	%		82	%		174	%
Net Assets, End of Period (in thousands)	$	149		$	120		$	274		$	589		$	286		$	31

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

22

A Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	11.93		$	10.56		$	9.91		$	15.65		$	12.85		$	11.03
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.05			0.09			0.11			0.12			0.11			0.06
Net Realized and    Unrealized Gain (Loss)		2.01			1.39			0.66			(5.41	)		2.92			2.11
Total From    Investment Operations		2.06			1.48			0.77			(5.29	)		3.03			2.17
Distributions
From Net    Investment Income		(0.11	)		(0.11	)		(0.12	)		(0.09	)		(0.04	)		—
From Net Realized Gains		—			—			—			(0.36	)		(0.19	)		(0.35	)
Total Distributions		(0.11	)		(0.11	)		(0.12	)		(0.45	)		(0.23	)		(0.35	)
Net Asset Value, End of Period	$	13.88		$	11.93		$	10.56		$	9.91		$	15.65		$	12.85
Total Return(3)		17.33	%		14.10	%		8.00	%		(34.73	)%		23.88	%		20.12	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.26	%(4)		1.27	%		1.26	%		1.26	%		1.25	%		1.25	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.78	%(4)		0.81	%		1.12	%		0.90	%		0.74	%		0.49	%
Portfolio Turnover Rate		8	%		29	%		64	%		97	%		82	%		174	%
Net Assets, End of Period (in thousands)	$	129,581		$	129,960		$	159,959		$	218,469		$	246,322		$	37,314

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

23

B Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	11.77		$	10.42		$	9.78		$	15.45		$	12.74		$	10.96
Income From Investment Operations
Net Investment    Income (Loss)(2)		—	(3)		0.01			0.03			0.02			0.01			(0.02	)
Net Realized and    Unrealized Gain (Loss)		1.99			1.37			0.66			(5.36	)		2.89			2.07
Total From    Investment Operations		1.99			1.38			0.69			(5.34	)		2.90			2.05
Distributions
From Net    Investment Income		(0.01	)		(0.03	)		(0.05	)		—			—			—
From Net Realized Gains		—			—			—			(0.33	)		(0.19	)		(0.27	)
Total Distributions		(0.01	)		(0.03	)		(0.05	)		(0.33	)		(0.19	)		(0.27	)
Net Asset Value, End of Period	$	13.75		$	11.77		$	10.42		$	9.78		$	15.45		$	12.74
Total Return(4)		16.84	%		13.23	%		7.17	%		(35.23	)%		23.01	%		19.04	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.01	%(5)		2.02	%		2.01	%		2.01	%		2.00	%		2.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.03	%(5)		0.06	%		0.37	%		0.15	%		(0.01	)%		(0.26	)%
Portfolio Turnover Rate		8	%		29	%		64	%		97	%		82	%		174	%
Net Assets, End of Period (in thousands)	$	4,054		$	3,838		$	4,043		$	4,195		$	4,889		$	1,498

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Per-share amount was less than $0.005.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

24

C Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	11.77		$	10.42		$	9.79		$	15.46		$	12.75		$	10.96
Income From Investment Operations
Net Investment    Income (Loss)(2)		—	(3)		0.01			0.03			0.02			—	(3)		(0.03	)
Net Realized and    Unrealized Gain (Loss)		1.99			1.37			0.65			(5.36	)		2.90			2.09
Total From    Investment Operations		1.99			1.38			0.68			(5.34	)		2.90			2.06
Distributions
From Net    Investment Income		(0.01	)		(0.03	)		(0.05	)		—			—			—
From Net Realized Gains		—			—			—			(0.33	)		(0.19	)		(0.27	)
Total Distributions		(0.01	)		(0.03	)		(0.05	)		(0.33	)		(0.19	)		(0.27	)
Net Asset Value, End of Period	$	13.75		$	11.77		$	10.42		$	9.79		$	15.46		$	12.75
Total Return(4)		16.93	%		13.23	%		7.06	%		(35.20	)%		22.99	%		19.13	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.01	%(5)		2.02	%		2.01	%		2.01	%		2.00	%		2.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.03	%(5)		0.06	%		0.37	%		0.15	%		(0.01	)%		(0.26	)%
Portfolio Turnover Rate		8	%		29	%		64	%		97	%		82	%		174	%
Net Assets, End of Period (in thousands)	$	15,954		$	14,816		$	15,311		$	18,919		$	24,544		$	4,530

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Per-share amount was less than $0.005.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

25

R Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	11.89		$	10.52		$	9.88		$	15.61		$	12.81		$	11.03
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.03			0.06			0.06			0.09			0.09			0.04
Net Realized and    Unrealized Gain (Loss)		2.00			1.39			0.68			(5.41	)		2.90			2.08
Total From    Investment Operations		2.03			1.45			0.74			(5.32	)		2.99			2.12
Distributions
From Net    Investment Income		(0.07	)		(0.08	)		(0.10	)		(0.05	)		—	(3)		—
From Net Realized Gains		—			—			—			(0.36	)		(0.19	)		(0.34	)
Total Distributions		(0.07	)		(0.08	)		(0.10	)		(0.41	)		(0.19	)		(0.34	)
Net Asset Value, End of Period	$	13.85		$	11.89		$	10.52		$	9.88		$	15.61		$	12.81
Total Return(4)		17.17	%		13.86	%		7.64	%		(34.92	)%		23.60	%		19.67	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.51	%(5)		1.52	%		1.51	%		1.51	%		1.50	%		1.50	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.53	%(5)		0.56	%		0.87	%		0.65	%		0.49	%		0.24	%
Portfolio Turnover Rate		8	%		29	%		64	%		97	%		82	%		174	%
Net Assets, End of Period (in thousands)	$	3,040		$	2,624		$	2,650		$	364		$	438		$	30

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Per-share amount was less than $0.005.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

26

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

27

Notes

28

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71834   1106

SEMIANNUAL REPORT     |      APRIL 30, 2011

Giftrust® Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	11
Statement of Operations	12
Statement of Changes in Net Assets	13
Notes to Financial Statements	14
Financial Highlights	19
Additional Information	20

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	10 years	Since Inception	Inception Date
Investor Class	TWGTX	18.34%	25.10%	7.61%	5.66%(2)	11.74%	11/25/83
Russell 3000 Growth Index	—	17.77%	21.62%	5.05%	2.38%	9.51%(3)	—

(1) Total returns for periods less than one year are not annualized.

(2) Returns would have been lower if a portion of the management fee had not been waived.

(3) Since 11/30/83, the date nearest the Investor Class’s inception for which data are available.

Total Annual Fund Operating Expenses

Investor Class      1.01%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. International investing involves special risks, such as political instability and currency fluctuations.

Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Apple, Inc.	6.9%
Oracle Corp.	3.4%
QUALCOMM, Inc.	3.2%
Exxon Mobil Corp.	3.1%
National Oilwell Varco, Inc.	3.1%
Caterpillar, Inc.	3.0%
Netflix, Inc.	2.5%
Express Scripts, Inc.	2.3%
Precision Castparts Corp.	2.3%
Cognizant Technology Solutions Corp., Class A	2.2%
Top Five Industries	% of net assets
Machinery	7.9%
Computers & Peripherals	7.4%
Energy Equipment & Services	6.9%
Software	6.5%
Oil, Gas & Consumable Fuels	4.9%
Types of Investments in Portfolio	% of net assets
Domestic Common Stocks	91.1%
Foreign Common Stocks(1)	8.6%
Total Common Stocks	99.7%
Temporary Cash Investments	0.3%
Other Assets and Liabilities(2)	—

(1) Includes depositary shares, dual listed securities and foreign ordinary shares.

(2) Category is less than 0.05% of total net assets.

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,183.40	$5.41	1.00%
Hypothetical
Investor Class	$1,000	$1,019.84	$5.01	1.00%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 99.7%
AEROSPACE & DEFENSE — 4.4%
BE Aerospace, Inc.(1)		445,325	$	17,185,092
Precision Castparts Corp.		158,628		24,511,198
TransDigm Group, Inc.(1)		72,639		6,050,829
				47,747,119
AUTOMOBILES — 0.8%
Hyundai Motor Co.		38,162		8,777,990
BEVERAGES — 1.4%
Coca-Cola Co. (The)		155,695		10,503,185
Hansen Natural Corp.(1)		65,510		4,333,486
				14,836,671
BIOTECHNOLOGY — 1.2%
Alexion Pharmaceuticals, Inc.(1)		81,845		7,929,962
United Therapeutics Corp.(1)		47,020		3,148,459
Vertex Pharmaceuticals, Inc.(1)		42,817		2,355,792
				13,434,213
CAPITAL MARKETS — 1.8%
Charles Schwab Corp. (The)		284,277		5,205,112
Goldman Sachs Group, Inc. (The)		43,436		6,559,270
Lazard Ltd., Class A		195,310		8,007,710
				19,772,092
CHEMICALS — 1.0%
Albemarle Corp.		145,856		10,290,141
COMMUNICATIONS EQUIPMENT — 4.1%
Aruba Networks, Inc.(1)		100,214		3,600,689
F5 Networks, Inc.(1)		60,119		6,093,662
QUALCOMM, Inc.		603,106		34,280,545
				43,974,896
COMPUTERS & PERIPHERALS — 7.4%
Apple, Inc.(1)		214,489		74,691,504
EMC Corp.(1)		193,305		5,478,264
				80,169,768
CONSTRUCTION & ENGINEERING — 0.4%
Foster Wheeler AG(1)		107,561		3,825,945
CONSUMER FINANCE — 1.0%
Discover Financial Services		444,617		11,044,286
CONTAINERS & PACKAGING — 0.3%
Rock-Tenn Co., Class A		45,131		3,117,198
DIVERSIFIED CONSUMER SERVICES — 0.5%
Weight Watchers International, Inc.		75,055		5,835,526
DIVERSIFIED FINANCIAL SERVICES — 0.7%
JPMorgan Chase & Co.		167,068		7,623,313
ELECTRICAL EQUIPMENT — 2.3%
Cooper Industries plc		150,476		9,923,892
Polypore International, Inc.(1)		55,459		3,425,703
Rockwell Automation, Inc.		135,570		11,812,214
				25,161,809
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 0.8%
Jabil Circuit, Inc.		216,654		4,298,415
Trimble Navigation Ltd.(1)		83,893		3,929,548
				8,227,963
ENERGY EQUIPMENT & SERVICES — 6.9%
Dril-Quip, Inc.(1)		37,846		2,897,490
FMC Technologies, Inc.(1)		143,859		6,686,566
Halliburton Co.		350,721		17,704,396
National Oilwell Varco, Inc.		436,851		33,502,103
Schlumberger Ltd.		153,144		13,744,674
				74,535,229
FOOD & STAPLES RETAILING — 4.0%
Costco Wholesale Corp.		226,923		18,362,609
Walgreen Co.		120,922		5,165,788
Whole Foods Market, Inc.		308,133		19,338,427
				42,866,824
FOOD PRODUCTS — 1.2%
Mead Johnson Nutrition Co.		196,530		13,143,926
HEALTH CARE EQUIPMENT & SUPPLIES — 2.7%
Baxter International, Inc.		185,398		10,549,146
C.R. Bard, Inc.		86,412		9,224,481
Cooper Cos., Inc. (The)		40,889		3,062,586
Varian Medical Systems, Inc.(1)		94,143		6,608,839
				29,445,052
HEALTH CARE PROVIDERS & SERVICES — 2.5%
Express Scripts, Inc.(1)		433,688		24,607,457
Odontoprev SA		171,800		2,745,393
				27,352,850
HEALTH CARE TECHNOLOGY — 1.7%
Allscripts Healthcare Solutions, Inc.(1)		202,005		4,351,188
SXC Health Solutions Corp.(1)		258,477		14,257,591
				18,608,779
HOTELS, RESTAURANTS & LEISURE — 4.8%
Arcos Dorados Holdings, Inc., Class A(1)		104,802		2,308,788
Chipotle Mexican Grill, Inc.(1)		18,984		5,064,741
Las Vegas Sands Corp.(1)		34,783		1,635,149
McDonald’s Corp.		201,014		15,741,406

8

	Shares		Value
Royal Caribbean Cruises Ltd.(1)	531,231	$	21,153,619
Yum! Brands, Inc.	112,616		6,040,722
			51,944,425
HOUSEHOLD DURABLES — 0.1%
KB Home	114,819		1,356,012
INDUSTRIAL CONGLOMERATES — 0.6%
General Electric Co.	294,645		6,025,490
INTERNET & CATALOG RETAIL — 3.8%
Netflix, Inc.(1)	114,717		26,691,204
priceline.com, Inc.(1)	27,048		14,795,527
			41,486,731
INTERNET SOFTWARE & SERVICES — 4.1%
Baidu, Inc. ADR(1)	93,735		13,921,522
Google, Inc., Class A(1)	26,938		14,656,966
OpenTable, Inc.(1)	36,813		4,096,919
SAVVIS, Inc.(1)	41,104		1,617,853
VeriSign, Inc.	264,111		9,761,543
			44,054,803
IT SERVICES — 3.9%
Cognizant Technology Solutions Corp., Class A(1)	288,684		23,931,904
International Business Machines Corp.	62,219		10,613,317
MasterCard, Inc., Class A	13,590		3,749,345
VeriFone Systems, Inc.(1)	70,434		3,861,192
			42,155,758
LEISURE EQUIPMENT & PRODUCTS — 0.3%
Brunswick Corp.	133,667		3,123,798
LIFE SCIENCES TOOLS & SERVICES — 1.7%
Agilent Technologies, Inc.(1)	261,134		13,033,198
Illumina, Inc.(1)	82,353		5,845,416
			18,878,614
MACHINERY — 7.9%
AGCO Corp.(1)	191,820		11,044,996
Caterpillar, Inc.	276,976		31,965,800
Chart Industries, Inc.(1)	71,205		3,461,275
Cummins, Inc.	127,800		15,359,004
Deere & Co.	177,377		17,294,257
Harsco Corp.	84,698		3,015,249
Titan International, Inc.	115,606		3,571,069
			85,711,650
MEDIA — 1.8%
CBS Corp., Class B	289,162		7,292,666
Focus Media Holding Ltd. ADR(1)	35,536		1,249,090
Imax Corp.(1)	325,499		11,418,505
			19,960,261
METALS & MINING — 0.2%
Cliffs Natural Resources, Inc.	26,455		2,479,363
OIL, GAS & CONSUMABLE FUELS — 4.9%
Concho Resources, Inc.(1)	82,736		8,840,342
Exxon Mobil Corp.	382,325		33,644,600
Linn Energy LLC	77,805		3,141,766
Pioneer Natural Resources Co.	32,113		3,282,912
SandRidge Energy, Inc.(1)	326,501		4,035,552
			52,945,172
PHARMACEUTICALS — 1.4%
Allergan, Inc.	71,423		5,682,414
Shire plc	88,829		2,750,917
Shire plc ADR	68,456		6,380,784
			14,814,115
REAL ESTATE MANAGEMENT & DEVELOPMENT — 0.8%
CB Richard Ellis Group, Inc., Class A(1)	312,953		8,358,975
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 1.9%
ARM Holdings plc	401,013		4,184,949
Broadcom Corp., Class A(1)	155,426		5,467,887
Cavium Networks, Inc.(1)	130,090		6,142,850
Cypress Semiconductor Corp.(1)	49,240		1,071,462
Veeco Instruments, Inc.(1)	65,804		3,364,558
			20,231,706
SOFTWARE — 6.5%
Check Point Software Technologies Ltd.(1)	74,321		4,082,452
Citrix Systems, Inc.(1)	93,014		7,844,801
Oracle Corp.	1,017,351		36,675,504
salesforce.com, inc.(1)	111,828		15,499,361
VMware, Inc., Class A(1)	65,272		6,228,907
			70,331,025
SPECIALTY RETAIL — 2.1%
Dick’s Sporting Goods, Inc.(1)	59,279		2,426,289
O’Reilly Automotive, Inc.(1)	172,863		10,209,289
PetSmart, Inc.	102,023		4,302,310
Williams-Sonoma, Inc.	130,593		5,669,042
			22,606,930
TEXTILES, APPAREL & LUXURY GOODS — 1.3%
Coach, Inc.	96,950		5,798,580
Lululemon Athletica, Inc.(1)	87,201		8,722,716
			14,521,296

9

Shares Value

TOBACCO — 2.3%
Altria Group, Inc.	228,314	$	6,127,948
Philip Morris International, Inc.	275,702		19,144,747
			25,272,695
TRADING COMPANIES & DISTRIBUTORS — 1.2%
Fastenal Co.	128,738		8,637,032
WESCO International, Inc.(1)	66,448		4,116,454
			12,753,486
WIRELESS TELECOMMUNICATION SERVICES — 1.0%
NII Holdings, Inc.(1)	98,553		4,097,834
SBA Communications Corp., Class A(1)	168,167		6,496,291
			10,594,125
TOTAL COMMON STOCKS (Cost $710,305,397)			1,079,398,020
Temporary Cash Investments — 0.3%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	56,869		56,869
Repurchase Agreement, Credit Suisse First Boston, Inc., (collateralized by various U.S. Treasury obligations, 1.375%, 5/15/13, valued at $3,366,002), in a joint trading account at 0.01%, dated 4/29/11, due 5/2/11 (Delivery value $3,300,003)			3,300,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $3,356,869)			3,356,869
TOTAL INVESTMENT SECURITIES — 100.0% (Cost $713,662,266)			1,082,754,889
OTHER ASSETS AND LIABILITIES(2)			373,962
TOTAL NET ASSETS — 100.0%		$	1,083,128,851

Forward Foreign Currency Exchange Contracts
Contracts to Sell		Counterparty	Settlement Date	Value	Unrealized Gain (Loss)
3,079,776	GBP for USD	Bank of America	5/31/11	$5,142,579	$(71,112)

(Value on Settlement Date $5,071,467)

Notes to Schedule of Investments

ADR = American Depositary Receipt

GBP = British Pound

USD = United States Dollar

(1) Non-income producing.

(2) Category is less than 0.05% of total net assets.

See Notes to Financial Statements.

10

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $713,662,266)	$	1,082,754,889
Cash		41,767
Foreign currency holdings, at value (cost of $10,247)		10,288
Receivable for investments sold		9,823,902
Receivable for capital shares sold		19,155
Dividends and interest receivable		360,597
		1,093,010,598
Liabilities
Payable for investments purchased		8,735,311
Payable for capital shares redeemed		201,450
Unrealized loss on forward foreign currency exchange contracts		71,112
Accrued management fees		873,874
		9,881,747
Net Assets	$	1,083,128,851
Investor Class Capital Shares, $0.01 Par Value
Shares authorized		200,000,000
Shares outstanding		35,109,577
Net Asset Value Per Share	$	30.85
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	728,752,239
Accumulated net investment loss		(546,063	)
Accumulated net realized loss		(14,099,046	)
Net unrealized appreciation		369,021,721
	$	1,083,128,851

See Notes to Financial Statements

11

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $9,408)	$	4,495,140
Interest		2,995
		4,498,135
Expenses:
Management fees		5,119,239
Directors’ fees and expenses		25,087
		5,144,326
Net investment income (loss)		(646,191	)
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		91,968,773
Foreign currency transactions (net of foreign tax expenses paid (refunded) of $59,456)		(95,487	)
		91,873,286
Change in net unrealized appreciation (depreciation) on:
Investments		80,888,838
Translation of assets and liabilities in foreign currencies		29,265
		80,918,103
Net realized and unrealized gain (loss)		172,791,389
Net Increase (Decrease) in Net Assets Resulting from Operations	$	172,145,198

See Notes to Financial Statements

12

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	(646,191	)	$	(1,928,945	)
Net realized gain (loss)		91,873,286			88,509,606
Change in net unrealized appreciation (depreciation)		80,918,103			113,572,450
Net increase (decrease) in net assets resulting from operations		172,145,198			200,153,111
Capital Share Transactions
Proceeds from shares sold		3,424,730			6,307,332
Payments for shares redeemed		(51,887,785	)		(84,853,156	)
Net increase (decrease) in net assets from capital share transactions		(48,463,055	)		(78,545,824	)
Net increase (decrease) in net assets		123,682,143			121,607,287
Net Assets
Beginning of period		959,446,708			837,839,421
End of period	$	1,083,128,851		$	959,446,708
Accumulated undistributed net investment income (loss)	$	(546,063	)	$	100,128
Transactions in Shares of the Fund
Sold		119,414			271,644
Redeemed		(1,806,078	)		(3,644,275	)
Net increase (decrease) in shares of the fund		(1,686,664	)		(3,372,631	)

See Notes to Financial Statements

13

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Giftrust Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing in equity securities of companies of any size that management believes will increase in value over time.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Forward foreign currency exchange contracts are valued at the mean of the latest bid and asked prices of the forward currency rates as provided by an independent pricing service.

The value of investments initially expressed in foreign currencies is translated into U.S. dollars at prevailing exchange rates.

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

14

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Foreign Currency Translations — All assets and liabilities initially expressed in foreign currencies are translated into U.S. dollars at prevailing exchange rates at period end. The fund may enter into spot foreign currency exchange contracts to facilitate transactions denominated in a foreign currency. Purchases and sales of investment securities, dividend and interest income, spot foreign currency exchange contracts, and expenses are translated at the rates of exchange prevailing on the respective dates of such transactions. Net realized and unrealized foreign currency exchange gains or losses related to investment securities are a component of net realized gain (loss) on investment transactions and change in net unrealized appreciation (depreciation) on investments, respectively. Certain countries impose taxes on the contract amount of purchases and sales of foreign currency contracts in their currency. The fund records the foreign tax expense, if any, as a reduction to the net realized gain (loss) on foreign currency transactions.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. Additionally, non-U.S. tax returns filed by the fund due to investments in certain foreign securities remain subject to examination by the relevant taxing authority for seven years from the date of filing. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

15

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee). The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on the daily net assets of the fund and paid monthly in arrears. The annual management fee is 1.00%.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, American Century Investment Services, Inc., and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMorgan Chase Bank (JPMCB) is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $367,016,278 and $409,044,344, respectively.

5. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

16

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2			Level 3
Investment Securities
Domestic Common Stocks	$	986,763,668		—			—
Foreign Common Stocks		74,175,103	$	18,459,249			—
Temporary Cash Investments		56,869		3,300,000			—
Total Value of Investment Securities	$	1,060,995,640	$	21,759,249			—
Other Financial Instruments
Total Unrealized Gain (Loss) on Forward Foreign Currency Exchange Contracts		—	$	(71,112	)		—

6. Derivative Instruments

Foreign Currency Risk — The fund is subject to foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The value of foreign investments held by a fund may be significantly affected by changes in foreign currency exchange rates. The dollar value of a foreign security generally decreases when the value of the dollar rises against the foreign currency in which the security is denominated and tends to increase when the value of the dollar declines against such foreign currency. A fund may enter into forward foreign currency exchange contracts to reduce a fund’s exposure to foreign currency exchange rate fluctuations. The net U.S. dollar value of foreign currency underlying all contractual commitments held by a fund and the resulting unrealized appreciation or depreciation are determined daily. Realized gain or loss is recorded upon the termination of the contract. Net realized and unrealized gains or losses occurring during the holding period of forward foreign currency exchange contracts are a component of net realized gain (loss) on foreign currency transactions and change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies, respectively. A fund bears the risk of an unfavorable change in the foreign currency exchange rate underlying the forward contract. Additionally, losses, up to the fair value, may arise if the counterparties do not perform under the contract terms. The risk of loss from non-performance by the counterparty may be reduced by the use of master netting agreements. The foreign currency risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

The value of foreign currency risk derivative instruments as of April 30, 2011, is disclosed on the Statement of Assets and Liabilities as a liability of $71,112 in unrealized loss on forward foreign currency exchange contracts. For the six months ended April 30, 2011, the effect of foreign currency risk derivative instruments on the Statement of Operations was $(49,994) in net realized gain (loss) on foreign currency transactions and $29,016 in change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies.

7. Risk Factors

There are certain risks involved in investing in foreign securities. These risks include those resulting from future adverse political, social, and economic developments, fluctuations in currency exchange rates, the possible imposition of exchange controls, and other foreign laws or restrictions.

17

8. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	714,771,045
Gross tax appreciation of investments	$	369,491,502
Gross tax depreciation of investments		(1,507,658	)
Net tax appreciation (depreciation) of investments	$	367,983,844

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(104,553,393), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers expire in 2017.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

18

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	26.07		$	20.86		$	19.08		$	31.53		$	20.13		$	17.28
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.02	)		(0.05	)		0.03			(0.13	)		(0.14	)		(0.05	)
Net Realized and    Unrealized Gain (Loss)		4.80			5.26			1.81			(12.32	)		11.54			2.90
Total From    Investment Operations		4.78			5.21			1.84			(12.45	)		11.40			2.85
Distributions
From Net    Investment Income		—			—			(0.06	)		—			—			—
Net Asset Value, End of Period	$	30.85		$	26.07		$	20.86		$	19.08		$	31.53		$	20.13
Total Return(3)		18.34	%		24.98	%		9.72	%		(39.49	)%		56.63	%		16.49	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.00	%(4)		1.01	%		1.00	%		1.00	%		1.00	%		1.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.13	)%(4)		(0.22	)%		0.19	%		(0.48	)%		(0.57	)%		(0.22	)%
Portfolio Turnover Rate		36	%		88	%		167	%		171	%		147	%		229	%
Net Assets, End of Period (in millions)	$	1,083		$	959		$	838		$	804		$	1,421		$	985

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

19

Additional Information

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

20

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71837   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

Growth Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	11
Statement of Operations	12
Statement of Changes in Net Assets	13
Notes to Financial Statements	14
Financial Highlights	21
Additional Information	26

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	10 years	Since Inception	Inception Date
Investor Class	TWCGX	17.06%	19.55%	6.17%	2.97%	13.67%	6/30/71(2)
Russell 1000 Growth Index	—	16.96%	20.87%	5.06%	2.11%	N/A(3)	—
Institutional Class	TWGIX	17.17%	19.84%	6.39%	3.19%	5.53%	6/16/97
A Class(4)    No sales charge*    With sales charge*	TCRAX	16.92% 10.20%	19.30% 12.45%	5.91% 4.67%	2.70% 2.09%	5.44% 4.99%	6/4/97
C Class    No sales charge*    With sales charge*	TWRCX	16.48% 15.48%	18.41% 18.41%	— —	— —	21.71%   21.71%	3/1/10
R Class	AGWRX	16.77%	19.00%	5.65%	—	6.80%	8/29/03

* Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. C Class shares redeemed within 12 months of purchase are subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

(2) Although the fund’s actual inception date was 10/31/58, this inception date corresponds with the investment advisor’s implementation of its current investment philosophy and practices.

(3) Index data not available prior to 12/29/78.

(4) Prior to March 1, 2010, the A Class was referred to as the Advisor Class and did not have a front-end sales charge. Performance prior to that date has been adjusted to reflect this charge.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class	C Class	R Class
1.00%	0.80%	1.25%	2.00%	1.50%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Exxon Mobil Corp.	5.0%
Apple, Inc.	4.7%
Oracle Corp.	2.8%
Schlumberger Ltd.	2.5%
Coca-Cola Co. (The)	2.3%
QUALCOMM, Inc.	2.2%
Accenture plc, Class A	1.8%
United Parcel Service, Inc., Class B	1.7%
Express Scripts, Inc.	1.7%
Cisco Systems, Inc.	1.7%
Top Five Industries	% of net assets
Computers & Peripherals	8.2%
Oil, Gas & Consumable Fuels	7.9%
Software	6.7%
Machinery	5.1%
IT Services	5.0%
Types of Investments in Portfolio	% of net assets
Common Stocks	98.8%
Temporary Cash Investments	1.5%
Other Assets and Liabilities	(0.3)%

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,170.60	$5.27	0.98%
Institutional Class	$1,000	$1,171.70	$4.20	0.78%
A Class	$1,000	$1,169.20	$6.62	1.23%
C Class	$1,000	$1,164.80	$10.63	1.98%
R Class	$1,000	$1,167.70	$7.95	1.48%
Hypothetical
Investor Class	$1,000	$1,019.93	$4.91	0.98%
Institutional Class	$1,000	$1,020.93	$3.91	0.78%
A Class	$1,000	$1,018.70	$6.16	1.23%
C Class	$1,000	$1,014.98	$9.89	1.98%
R Class	$1,000	$1,017.46	$7.40	1.48%

* Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 98.8%
AEROSPACE & DEFENSE — 2.3%
Honeywell International, Inc.		1,826,000	$	111,805,980
Rockwell Collins, Inc.		371,100		23,416,410
Textron, Inc.		1,824,100		47,609,010
				182,831,400
AIR FREIGHT & LOGISTICS — 1.7%
United Parcel Service, Inc., Class B		1,832,500		137,382,525
AUTO COMPONENTS — 2.1%
Autoliv, Inc.		854,500		68,471,085
BorgWarner, Inc.(1)		1,257,900		97,160,196
				165,631,281
AUTOMOBILES — 0.6%
Harley-Davidson, Inc.		1,329,300		49,529,718
BEVERAGES — 3.2%
Coca-Cola Co. (The)		2,772,700		187,046,342
Hansen Natural Corp.(1)		362,800		23,999,220
PepsiCo, Inc.		696,400		47,974,996
				259,020,558
BIOTECHNOLOGY — 1.6%
Alexion Pharmaceuticals, Inc.(1)		101,600		9,844,024
Amgen, Inc.(1)		892,500		50,738,625
Gilead Sciences, Inc.(1)		1,220,000		47,384,800
Human Genome Sciences, Inc.(1)		634,100		18,686,927
				126,654,376
CAPITAL MARKETS — 2.1%
BlackRock, Inc.		378,300		74,124,102
Charles Schwab Corp. (The)		3,316,200		60,719,622
T. Rowe Price Group, Inc.		548,900		35,266,825
				170,110,549
CHEMICALS — 3.2%
E.I. du Pont de Nemours & Co.		1,635,600		92,885,724
LyondellBasell Industries NV, Class A(1)		942,800		41,954,600
PPG Industries, Inc.		910,100		86,159,167
Sigma-Aldrich Corp.		532,800		37,605,024
				258,604,515
COMMUNICATIONS EQUIPMENT — 4.8%
Cisco Systems, Inc.		7,536,100		132,333,916
Juniper Networks, Inc.(1)		1,442,800		55,302,524
QUALCOMM, Inc.		3,161,300		179,688,292
Riverbed Technology, Inc.(1)		576,500		20,258,210
				387,582,942
COMPUTERS & PERIPHERALS — 8.2%
Apple, Inc.(1)		1,080,400		376,227,692
Dell, Inc.(1)		4,507,300		69,908,223
EMC Corp.(1)		4,564,200		129,349,428
NetApp, Inc.(1)		1,545,700		80,345,486
				655,830,829
CONSUMER FINANCE — 1.2%
American Express Co.		1,973,100		96,839,748
DIVERSIFIED TELECOMMUNICATION SERVICES — 0.5%
Verizon Communications, Inc.		1,007,200		38,052,016
ELECTRICAL EQUIPMENT — 1.9%
Emerson Electric Co.		823,200		50,017,632
Rockwell Automation, Inc.		1,125,400		98,056,102
				148,073,734
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 0.6%
Jabil Circuit, Inc.		2,198,600		43,620,224
ENERGY EQUIPMENT & SERVICES — 3.4%
Core Laboratories NV		272,500		26,154,550
Halliburton Co.		894,100		45,134,168
Schlumberger Ltd.		2,251,500		202,072,125
				273,360,843
FOOD & STAPLES RETAILING — 2.9%
Costco Wholesale Corp.		1,449,200		117,269,264
Walgreen Co.		1,963,100		83,863,632
Whole Foods Market, Inc.		502,100		31,511,796
				232,644,692
FOOD PRODUCTS — 2.3%
General Mills, Inc.		871,400		33,618,612
Hershey Co. (The)		979,000		56,498,090
Kellogg Co.		1,192,800		68,311,656
Mead Johnson Nutrition Co.		429,100		28,698,208
				187,126,566
HEALTH CARE EQUIPMENT & SUPPLIES — 4.0%
Cooper Cos., Inc. (The)		246,100		18,432,890
Covidien plc		1,368,000		76,183,920
DENTSPLY International, Inc.		387,400		14,542,996
Edwards Lifesciences Corp.(1)		327,900		28,314,165
Gen-Probe, Inc.(1)		291,100		24,138,012
Intuitive Surgical, Inc.(1)		87,800		30,703,660
Medtronic, Inc.		1,505,100		62,837,925
St. Jude Medical, Inc.		752,100		40,192,224
Zimmer Holdings, Inc.(1)		428,200		27,940,050
				323,285,842

8

Shares Value

HEALTH CARE PROVIDERS & SERVICES — 1.7%
Express Scripts, Inc.(1)	2,380,800	$	135,086,592
HOTELS, RESTAURANTS & LEISURE — 3.3%
Chipotle Mexican Grill, Inc.(1)	40,700		10,858,353
Las Vegas Sands Corp.(1)	640,700		30,119,307
McDonald’s Corp.	1,429,000		111,904,990
Starbucks Corp.	1,375,700		49,786,583
Starwood Hotels & Resorts Worldwide, Inc.	1,077,100		64,162,847
			266,832,080
HOUSEHOLD DURABLES — 0.4%
Whirlpool Corp.	342,700		29,533,886
HOUSEHOLD PRODUCTS — 1.0%
Church & Dwight Co., Inc.	284,600		23,473,808
Procter & Gamble Co. (The)	898,000		58,280,200
			81,754,008
INDUSTRIAL CONGLOMERATES — 1.3%
General Electric Co.	5,050,800		103,288,860
INSURANCE — 0.8%
Aflac, Inc.	1,199,500		67,399,905
INTERNET & CATALOG RETAIL — 0.4%
Netflix, Inc.(1)	140,000		32,573,800
INTERNET SOFTWARE & SERVICES — 1.5%
Google, Inc., Class A(1)	214,300		116,600,630
IT SERVICES — 5.0%
Accenture plc, Class A	2,457,300		140,385,549
Automatic Data Processing, Inc.	1,354,900		73,638,815
International Business Machines Corp.	741,400		126,468,012
MasterCard, Inc., Class A	216,900		59,840,541
			400,332,917
LIFE SCIENCES TOOLS & SERVICES — 0.5%
Bruker Corp.(1)	396,700		7,830,858
Thermo Fisher Scientific, Inc.(1)	517,700		31,056,823
			38,887,681
MACHINERY — 5.1%
Caterpillar, Inc.	649,600		74,970,336
Deere & Co.	902,700		88,013,250
Eaton Corp.	1,877,600		100,507,928
Illinois Tool Works, Inc.	1,676,900		97,947,729
Joy Global, Inc.	492,600		49,727,970
			411,167,213
MEDIA — 1.7%
Scripps Networks Interactive, Inc., Class A	1,030,000		52,962,600
Walt Disney Co. (The)	1,899,700		81,877,070
			134,839,670
METALS & MINING — 2.2%
Cliffs Natural Resources, Inc.	796,400		74,638,608
Freeport-McMoRan Copper & Gold, Inc.	1,229,500		67,659,385
Newmont Mining Corp.	503,000		29,480,830
			171,778,823
MULTILINE RETAIL — 1.5%
Kohl’s Corp.	736,100		38,799,831
Target Corp.	1,678,700		82,424,170
			121,224,001
OIL, GAS & CONSUMABLE FUELS — 7.9%
Cimarex Energy Co.	386,400		42,731,976
ConocoPhillips	888,700		70,145,091
Exxon Mobil Corp.	4,538,600		399,396,800
Occidental Petroleum Corp.	584,300		66,779,647
Southwestern Energy Co.(1)	1,263,000		55,395,180
			634,448,694
PERSONAL PRODUCTS — 0.4%
Estee Lauder Cos., Inc. (The), Class A	327,500		31,767,500
PHARMACEUTICALS — 2.7%
Abbott Laboratories	2,169,200		112,885,168
Allergan, Inc.	950,300		75,605,868
Novo Nordisk A/S B Shares	247,000		31,223,908
			219,714,944
REAL ESTATE MANAGEMENT & DEVELOPMENT — 0.6%
CB Richard Ellis Group, Inc., Class A(1)	1,646,500		43,978,015
ROAD & RAIL — 0.6%
Union Pacific Corp.	465,500		48,165,285
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 2.8%
Altera Corp.	1,134,700		55,259,890
Broadcom Corp., Class A(1)	324,900		11,429,982
Linear Technology Corp.	1,530,700		53,268,360
RF Micro Devices, Inc.(1)	1,593,500		10,612,710
Texas Instruments, Inc.	2,040,900		72,513,177
Xilinx, Inc.	526,800		18,364,248
			221,448,367
SOFTWARE — 6.7%
Citrix Systems, Inc.(1)	459,400		38,745,796
CommVault Systems, Inc.(1)	234,300		9,229,077
Intuit, Inc.(1)	745,300		41,408,868
Microsoft Corp.	3,528,500		91,811,570
Oracle Corp.	6,283,300		226,512,965
Red Hat, Inc.(1)	1,076,600		51,106,202
salesforce.com, inc.(1)	182,900		25,349,940
VMware, Inc., Class A(1)	584,751		55,802,788
			539,967,206

9

Shares Value

SPECIALTY RETAIL — 3.1%
American Eagle Outfitters, Inc.	1,577,000	$	24,538,120
Home Depot, Inc. (The)	3,276,000		121,670,640
Limited Brands, Inc.	1,781,900		73,343,004
OfficeMax, Inc.(1)	880,500		8,769,780
Williams-Sonoma, Inc.	537,000		23,311,170
			251,632,714
WIRELESS TELECOMMUNICATION SERVICES — 1.0%
Crown Castle International Corp.(1)	1,886,400		80,851,104
TOTAL COMMON STOCKS (Cost $6,521,361,757)			7,919,456,253
Temporary Cash Investments — 1.5%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	74,106		74,106
Repurchase Agreement, Credit Suisse First Boston, Inc., (collateralized by various U.S. Treasury obligations, 1.375%, 5/15/13, valued at $122,604,062), in a joint trading account at 0.01%, dated 4/29/11, due 5/2/11 (Delivery value $120,200,100)			120,200,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $120,274,106)			120,274,106
TOTAL INVESTMENT SECURITIES — 100.3% (Cost $6,641,635,863)			8,039,730,359
OTHER ASSETS AND LIABILITIES — (0.3)%			(20,554,941	)
TOTAL NET ASSETS — 100.0%		$	8,019,175,418

Forward Foreign Currency Exchange Contracts
Contracts to Sell		Counterparty	Settlement Date	Value	Unrealized Gain (Loss)
101,868,975	DKK for USD	UBS AG	5/31/11	$20,219,400	$(270,633)

(Value on Settlement Date $19,948,767)

Notes to Schedule of Investments

DKK = Danish Krone

USD = United States Dollar

(1) Non-income producing.

See Notes to Financial Statements.

10

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $6,641,635,863)	$	8,039,730,359
Foreign currency holdings, at value (cost of $403,392)		403,392
Receivable for investments sold		107,457,260
Receivable for capital shares sold		12,203,979
Dividends and interest receivable		5,971,623
		8,165,766,613
Liabilities
Payable for investments purchased		133,545,177
Payable for capital shares redeemed		6,712,382
Unrealized loss on forward foreign currency exchange contracts		270,633
Accrued management fees		5,940,543
Distribution and service fees payable		122,460
		146,591,195
Net Assets	$	8,019,175,418
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	6,480,259,730
Undistributed net investment income		23,683,144
Undistributed net realized gain		117,406,637
Net unrealized appreciation		1,397,825,907
	$	8,019,175,418

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$5,570,604,692	198,916,400	$28.00
Institutional Class, $0.01 Par Value	$1,905,136,323	67,462,252	$28.24
A Class, $0.01 Par Value	$486,349,965	17,640,359	$27.57*
C Class, $0.01 Par Value	$12,903,852	464,491	$27.78
R Class, $0.01 Par Value	$44,180,586	1,610,878	$27.43

* Maximum offering price $29.25 (net asset value divided by 0.9425)

See Notes to Financial Statements.

11

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $90,635)	$	56,914,132
Interest		41,249
		56,955,381
Expenses:
Management fees		32,414,975
Distribution and service fees:
A Class		529,618
C Class		44,482
R Class		78,243
Directors’ fees and expenses		172,206
		33,239,524
Net investment income (loss)		23,715,857
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		356,762,830
Foreign currency transactions		(1,400,155	)
		355,362,675
Change in net unrealized appreciation (depreciation) on:
Investments		686,413,810
Translation of assets and liabilities in foreign currencies		(218,167	)
		686,195,643
Net realized and unrealized gain (loss)		1,041,558,318
Net Increase (Decrease) in Net Assets Resulting from Operations	$	1,065,274,175

See Notes to Financial Statements.

12

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	23,715,857		$	21,711,027
Net realized gain (loss)		355,362,675			481,896,410
Change in net unrealized appreciation (depreciation)		686,195,643			323,115,779
Net increase (decrease) in net assets resulting from operations		1,065,274,175			826,723,216
Distributions to Shareholders
From net investment income:
Investor Class		(16,085,104	)		(9,474,213	)
Institutional Class		(6,371,247	)		(2,809,220	)
A Class		(354,453	)		(22,537	)
Decrease in net assets from distributions		(22,810,804	)		(12,305,970	)
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		1,034,126,064			984,370,677
Net increase (decrease) in net assets		2,076,589,435			1,798,787,923
Net Assets
Beginning of period		5,942,585,983			4,143,798,060
End of period	$	8,019,175,418		$	5,942,585,983
Undistributed net investment income	$	23,683,144		$	22,778,091

See Notes to Financial Statements.

13

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Growth Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing primarily in equity securities of larger-sized companies that management believes will increase in value over time.

The fund is authorized to issue the Investor Class, the Institutional Class, the A Class (formerly Advisor Class), the C Class and the R Class. The A Class may incur an initial sales charge. The A Class and C Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee. Sale of the C Class commenced on March 1, 2010.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Forward foreign currency exchange contracts are valued at the mean of the latest bid and asked prices of the forward currency rates as provided by an independent pricing service.

The value of investments initially expressed in foreign currencies is translated into U.S. dollars at prevailing exchange rates.

14

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Foreign Currency Translations — All assets and liabilities initially expressed in foreign currencies are translated into U.S. dollars at prevailing exchange rates at period end. The fund may enter into spot foreign currency exchange contracts to facilitate transactions denominated in a foreign currency. Purchases and sales of investment securities, dividend and interest income, spot foreign currency exchange contracts, and expenses are translated at the rates of exchange prevailing on the respective dates of such transactions. Net realized and unrealized foreign currency exchange gains or losses related to investment securities are a component of net realized gain (loss) on investment transactions and change in net unrealized appreciation (depreciation) on investments, respectively.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

15

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The strategy assets of the fund include the assets of NT Growth Fund, one fund in a series issued by the corporation. The annual management fee schedule ranges from 0.800% to 1.000% for the Investor Class, A Class, C Class and R Class. The Institutional Class is 0.200% less at each point within the range. The effective annual management fee for each class for the six months ended April 30, 2011 was 0.98% for the Investor Class, A Class, C Class and R Class and 0.78% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a separate Master Distribution and Individual Shareholder Services Plan for each of the A Class, C Class and R Class (collectively the plans), pursuant to Rule 12b-1 of the 1940 Act. The plans provide that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The plans provide that the C Class will pay ACIS an annual distribution and service fee of 1.00%, of which 0.25% is paid for individual shareholder services and 0.75% is paid for distribution services. The plans provide that the R Class will pay ACIS an annual distribution and service fee of 0.50%. The fees are computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services. Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a securities lending agreement with JPMorgan Chase Bank (JPMCB) and a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMCB is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $2,846,320,172 and $1,864,843,814, respectively.

16

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010(1)
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		800,000,000						800,000,000
Sold		27,253,442		$	720,592,453			42,868,834		$	951,268,051
Issued in connection with reorganization (Note 9)		—			—			1,023,911			24,573,857
Issued in reinvestment of distributions		592,046			15,180,061			384,127			8,458,476
Redeemed		(13,902,889	)		(365,710,741	)		(25,562,853	)		(568,903,119	)
		13,942,599			370,061,773			18,714,019			415,397,265
Institutional Class/Shares Authorized		150,000,000						150,000,000
Sold		24,905,887			669,732,365			25,469,004			591,790,668
Issued in connection with reorganization (Note 9)		—			—			53,875			1,305,390
Issued in reinvestment of distributions		238,680			6,165,100			122,616			2,720,853
Redeemed		(3,361,055	)		(88,640,659	)		(6,807,256	)		(152,879,506	)
		21,783,512			587,256,806			18,838,239			442,937,405
A Class/Shares Authorized		310,000,000						310,000,000
Sold		4,776,556			124,926,547			5,917,194			128,488,284
Issued in connection with reorganization (Note 9)		—			—			1,719,102			40,570,799
Issued in reinvestment of distributions		12,885			325,465			964			20,921
Redeemed		(2,789,238	)		(73,059,806	)		(2,746,133	)		(59,876,656	)
		2,000,203			52,192,206			4,891,127			109,203,348
C Class/Shares Authorized		20,000,000						20,000,000
Sold		235,566			6,235,701			56,605			1,279,112
Issued in connection with reorganization (Note 9)		—			—			204,997			4,889,189
Redeemed		(31,836	)		(830,583	)		(841	)		(17,696	)
		203,730			5,405,118			260,761			6,150,605
R Class/Shares Authorized		30,000,000						30,000,000
Sold		944,273			24,369,246			559,790			12,252,871
Issued in connection with reorganization (Note 9)		—			—			92,918			2,182,649
Redeemed		(198,753	)		(5,159,085	)		(172,171	)		(3,753,466	)
		745,520			19,210,161			480,537			10,682,054
Net increase (decrease)		38,675,564		$	1,034,126,064			43,184,683		$	984,370,677

(1) March 1, 2010 (commencement of sale) through October 31, 2010 for the C Class.

17

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2			Level 3
Investment Securities
Common Stocks	$	7,888,232,345	$	31,223,908			—
Temporary Cash Investments		74,106		120,200,000			—
Total Value of Investment Securities	$	7,888,306,451	$	151,423,908			—
Other Financial Instruments
Total Unrealized Gain (Loss) on Forward Foreign Currency Exchange Contracts		—	$	(270,633	)		—

7. Derivative Instruments

Foreign Currency Risk — The fund is subject to foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The value of foreign investments held by a fund may be significantly affected by changes in foreign currency exchange rates. The dollar value of a foreign security generally decreases when the value of the dollar rises against the foreign currency in which the security is denominated and tends to increase when the value of the dollar declines against such foreign currency. A fund may enter into forward foreign currency exchange contracts to reduce a fund’s exposure to foreign currency exchange rate fluctuations. The net U.S. dollar value of foreign currency underlying all contractual commitments held by a fund and the resulting unrealized appreciation or depreciation are determined daily. Realized gain or loss is recorded upon the termination of the contract. Net realized and unrealized gains or losses occurring during the holding period of forward foreign currency exchange contracts are a component of net realized gain (loss) on foreign currency transactions and change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies, respectively. A fund bears the risk of an unfavorable change in the foreign currency exchange rate underlying the forward contract. Additionally, losses, up to the fair value, may arise if the counterparties do not perform under the contract terms. The risk of loss from non-performance by the counterparty may be reduced by the use of master netting agreements. The foreign currency risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

18

The value of foreign currency risk derivative instruments as of April 30, 2011, is disclosed on the Statement of Assets and Liabilities as a liability of $270,633 in unrealized loss on forward foreign currency exchange contracts. For the six months ended April 30, 2011, the effect of foreign currency risk derivative instruments on the Statement of Operations was $(1,421,305) in net realized gain (loss) on foreign currency transactions and $(220,111) in change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies.

8. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	6,654,199,382
Gross tax appreciation of investments	$	1,468,099,829
Gross tax depreciation of investments		(82,568,852	)
Net tax appreciation (depreciation) of investments	$	1,385,530,977

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(218,430,712), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers of $(13,506,140), $(4,346,487) and $(200,578,085) expire in 2015, 2016 and 2017, respectively.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

19

9. Reorganization Plan

On June 10, 2010, the Board of Directors approved a plan of reorganization (the reorganization), pursuant to which Growth acquired all of the assets of Capital Growth Fund (Capital Growth), a fund in a series issued by the corporation, in exchange for shares of equal value of Growth and assumption by Growth of certain ordinary course liabilities of Capital Growth. The financial statements and performance history of Growth were carried over post-reorganization. The reorganization was effective at the close of business on October 29, 2010.

The reorganization was accomplished by a tax-free exchange of shares. On October 29, 2010, Capital Growth exchanged its shares for shares of Growth as follows:

Original Fund/Class	Shares Exchanged	New Fund/Class	Shares Received
Capital Growth — Investor Class	2,077,088	Growth — Investor Class	1,023,911
Capital Growth — Institutional Class	109,789	Growth — Institutional Class	53,875
Capital Growth — A Class	3,382,474	Growth — A Class	1,681,204
Capital Growth — B Class	80,143	Growth — A Class	37,898
Capital Growth — C Class	438,099	Growth — C Class	204,997
Capital Growth — R Class	187,997	Growth — R Class	92,918

The net assets of Capital Growth and Growth immediately before the reorganization were $73,521,884 and $5,869,064,099, respectively. Capital Growth’s unrealized appreciation of $13,044,432 was combined with that of Growth. Immediately after the reorganization, the combined net assets were $5,942,585,983. Growth acquired capital loss carryovers of $(1,831,877) from Capital Growth.

Assuming the reorganization had been completed on November 1, 2009, the beginning of the annual reporting period, the pro forma results of operations for the year ended October 31, 2010, were as follows:

Net investment income (loss)	$	21,800,994
Net realized and unrealized gain (loss)		813,269,412
Net increase (decrease) in net assets resulting from operations	$	835,070,406

Because the reorganization was completed at the close of business on the last business day of the period, no revenue and earnings of Capital Growth were included in the Statement of Operations.

20

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	24.00		$	20.28		$	17.69		$	26.78		$	21.99		$	19.80
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.09			0.10			0.09			0.04			0.04			0.02
Net Realized and    Unrealized Gain (Loss)		4.00			3.68			2.58			(9.10	)		4.76			2.26
Total From    Investment Operations		4.09			3.78			2.67			(9.06	)		4.80			2.28
Distributions
From Net    Investment Income		(0.09	)		(0.06	)		(0.08	)		(0.03	)		(0.01	)		(0.09	)
Net Asset Value, End of Period	$	28.00		$	24.00		$	20.28		$	17.69		$	26.78		$	21.99
Total Return(3)		17.06	%		18.65	%		15.25	%		(33.86	)%		21.86	%		11.51	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.98	%(4)		1.00	%		1.00	%		1.00	%		1.00	%		1.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.66	%(4)		0.43	%		0.50	%		0.16	%		0.15	%		0.09	%
Portfolio Turnover Rate		27	%		86	%		114	%		129	%		112	%		127	%
Net Assets, End of Period (in millions)	$	5,571		$	4,440		$	3,372		$	2,617		$	4,133		$	3,946

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

21

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	24.23		$	20.47		$	17.86		$	27.03		$	22.19		$	19.98
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.11			0.14			0.12			0.08			0.09			0.06
Net Realized and    Unrealized Gain (Loss)		4.04			3.72			2.61			(9.17	)		4.81			2.27
Total From    Investment Operations		4.15			3.86			2.73			(9.09	)		4.90			2.33
Distributions
From Net    Investment Income		(0.14	)		(0.10	)		(0.12	)		(0.08	)		(0.06	)		(0.12	)
Net Asset Value, End of Period	$	28.24		$	24.23		$	20.47		$	17.86		$	27.03		$	22.19
Total Return(3)		17.17	%		18.90	%		15.45	%		(33.71	)%		22.13	%		11.70	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.78	%(4)		0.80	%		0.80	%		0.80	%		0.80	%		0.80	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.86	%(4)		0.63	%		0.70	%		0.36	%		0.35	%		0.29	%
Portfolio Turnover Rate		27	%		86	%		114	%		129	%		112	%		127	%
Net Assets, End of Period (in thousands)	$	1,905,136		$	1,106,748		$	549,496		$	286,262		$	284,695		$	759,816

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

22

A Class(1)
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(2)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	23.60		$	19.94		$	17.40		$	26.36		$	21.68		$	19.53
Income From Investment Operations
Net Investment    Income (Loss)(3)		0.05			0.04			0.04			(0.02	)		(0.04	)		(0.03	)
Net Realized and    Unrealized Gain (Loss)		3.94			3.62			2.54			(8.94	)		4.72			2.22
Total From    Investment Operations		3.99			3.66			2.58			(8.96	)		4.68			2.19
Distributions
From Net    Investment Income		(0.02	)		—	(4)		(0.04	)		—			—			(0.04	)
Net Asset Value, End of Period	$	27.57		$	23.60		$	19.94		$	17.40		$	26.36		$	21.68
Total Return(5)		16.92	%		18.37	%		14.99	%		(34.03	)%		21.59	%		11.23	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.23	%(6)		1.25	%		1.25	%		1.25	%		1.25	%		1.25	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.41	%(6)		0.18	%		0.25	%		(0.09	)%		(0.10	)%		(0.16	)%
Portfolio Turnover Rate		27	%		86	%		114	%		129	%		112	%		127	%
Net Assets, End of Period (in thousands)	$	486,350		$	369,142		$	214,371		$	141,441		$	206,837		$	85,953

(1) Prior to March 1, 2010, the A Class was referred to as the Advisor Class.

(2) Six months ended April 30, 2011 (unaudited).

(3) Computed using average shares outstanding throughout the period.

(4) Per-share amount was less than $0.005.

(5) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(6) Annualized.

See Notes to Financial Statements.

23

C Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	23.85		$	22.10
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.05	)		(0.10	)
Net Realized and Unrealized Gain (Loss)		3.98			1.85
Total From Investment Operations		3.93			1.75
Net Asset Value, End of Period	$	27.78		$	23.85
Total Return(4)		16.48	%		7.92	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.98	%(5)		2.00	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.34	)%(5)		(0.66	)%(5)
Portfolio Turnover Rate		27	%		86	%(6)
Net Assets, End of Period (in thousands)	$	12,904		$	6,219

(1) Six months ended April 30, 2011 (unaudited).

(2) March 1, 2010 (commencement of sale) through October 31, 2010.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2010.

See Notes to Financial Statements.

24

R Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	23.49		$	19.90		$	17.35		$	26.37		$	21.74		$	19.59
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.01			(0.02	)		(0.01	)		(0.08	)		(0.10	)		(0.11	)
Net Realized and    Unrealized Gain (Loss)		3.93			3.61			2.56			(8.94	)		4.73			2.26
Total From    Investment Operations		3.94			3.59			2.55			(9.02	)		4.63			2.15
Distributions
From Net    Investment Income		—			—			—	(3)		—			—			—
Net Asset Value, End of Period	$	27.43		$	23.49		$	19.90		$	17.35		$	26.37		$	21.74
Total Return(4)		16.77	%		18.10	%		14.67	%		(34.21	)%		21.30	%		10.97	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.48	%(5)		1.50	%		1.50	%		1.50	%		1.50	%		1.50	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.16	%(5)		(0.07	)%		0.00	%(6)		(0.34	)%		(0.35	)%		(0.41	)%
Portfolio Turnover Rate		27	%		86	%		114	%		129	%		112	%		127	%
Net Assets, End of Period (in thousands)	$	44,181		$	20,325		$	7,656		$	3,280		$	2,383		$	298

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Per-share amount was less than $0.005.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Ratio was less than 0.005%.

See Notes to Financial Statements.

25

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

26

Notes

27

Notes

28

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71833   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

Heritage Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	6
Shareholder Fee Example	7
Schedule of Investments	9
Statement of Assets and Liabilities	12
Statement of Operations	13
Statement of Changes in Net Assets	14
Notes to Financial Statements	15
Financial Highlights	21
Additional Information	27

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	10 years	Since Inception	Inception Date
Investor Class	TWHIX	20.46%	28.99%	9.56%	7.82%	12.15%	11/10/87
Russell Midcap Growth Index	—	22.62%	27.40%	5.59%	5.68%	11.10%(2)	—
Russell Midcap Index	—	20.67%	23.36%	5.14%	7.95%	12.33%(2)	—
Institutional Class	ATHIX	20.59%	29.29%	9.78%	8.05%	9.46%	6/16/97
A Class(3)    No sales charge*    With sales charge*	ATHAX	20.37% 13.46%	28.70% 21.28%	9.29% 8.00%	7.55% 6.91%	8.65%    8.18%	7/11/97
B Class   No sales charge*    With sales charge*	ATHBX	19.88% 14.88%	27.69% 23.69%	— —	— —	2.73%    1.94%	9/28/07
C Class   No sales charge*    With sales charge*	AHGCX	19.89% 18.89%	27.75% 27.75%	8.48% 8.48%	— —	6.88%    6.88%	6/26/01
R Class	ATHWX	20.20%	28.37%	—	—	3.25%	9/28/07

*Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. B Class shares redeemed within six years of purchase are subject to a CDSC that declines from 5.00% during the first year after purchase to 0.00% the sixth year after purchase. C Class shares redeemed within 12 months of purchase are subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

(2) Since 10/31/87, the date nearest the Investor Class’s inception for which data are available.

(3) Prior to September 4, 2007, the A Class was referred to as the Advisor Class and did not have a front-end sales charge. Performance prior to that date has been adjusted to reflect this charge.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. International investing involves special risks, such as political instability and currency fluctuations.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the indices are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the indices do not.

4

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class	B Class	C Class	R Class
1.01%	0.81%	1.26%	2.01%	2.01%	1.51%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. International investing involves special risks, such as political instability and currency fluctuations.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the indices are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the indices do not.

5

Fund Characteristics

APRIL 30, 2011

Top Ten Holdings	% of net assets
Netflix, Inc.	2.8%
priceline.com, Inc.	2.2%
Royal Caribbean Cruises Ltd.	2.1%
BE Aerospace, Inc.	2.1%
SXC Health Solutions Corp.	2.0%
Whole Foods Market, Inc.	1.9%
VeriSign, Inc.	1.8%
Apple, Inc.	1.8%
O’Reilly Automotive, Inc.	1.8%
National Oilwell Varco, Inc.	1.7%

Top Five Industries	% of net assets
Machinery	7.4%
Internet & Catalog Retail	5.0%
Internet Software & Services	4.5%
Specialty Retail	4.4%
Energy Equipment & Services	4.3%

Types of Investments in Portfolio	% of net assets
Domestic Common Stocks	89.1%
Foreign Common Stocks*	9.7%
Total Common Stocks	98.8%
Temporary Cash Investments	1.3%
Other Assets and Liabilities	(0.1)%

*Includes depositary shares, dual listed securities and foreign ordinary shares.

6

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

7

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 - 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,204.60	$5.52	1.01%
Institutional Class	$1,000	$1,205.90	$4.43	0.81%
A Class	$1,000	$1,203.70	$6.88	1.26%
B Class	$1,000	$1,198.80	$10.96	2.01%
C Class	$1,000	$1,198.90	$10.96	2.01%
R Class	$1,000	$1,202.00	$8.24	1.51%
Hypothetical
Investor Class	$1,000	$1,019.79	$5.06	1.01%
Institutional Class	$1,000	$1,020.78	$4.06	0.81%
A Class	$1,000	$1,018.55	$6.31	1.26%
B Class	$1,000	$1,014.83	$10.04	2.01%
C Class	$1,000	$1,014.83	$10.04	2.01%
R Class	$1,000	$1,017.31	$7.55	1.51%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

8

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 98.8%
AEROSPACE & DEFENSE — 3.2%
BE Aerospace, Inc.(1)		2,329,184	$	89,883,211
TransDigm Group, Inc.(1)		536,300		44,673,790
				134,557,001
AUTO COMPONENTS — 0.9%
BorgWarner, Inc.(1)		485,900		37,530,916
AUTOMOBILES — 0.5%
Harley-Davidson, Inc.		527,800		19,665,828
BEVERAGES — 0.7%
Hansen Natural Corp.(1)		434,900		28,768,635
BIOTECHNOLOGY — 3.2%
Alexion Pharmaceuticals, Inc.(1)		607,700		58,880,053
United Therapeutics Corp.(1)		563,900		37,758,744
Vertex Pharmaceuticals, Inc.(1)		683,200		37,589,664
				134,228,461
CAPITAL MARKETS — 2.3%
KKR & Co. LP		1,344,100		25,484,136
Lazard Ltd., Class A		1,067,400		43,763,400
Raymond James Financial, Inc.		705,900		26,471,250
				95,718,786
CHEMICALS — 1.6%
Albemarle Corp.		965,400		68,108,970
COMMERCIAL BANKS — 0.5%
East West Bancorp., Inc.		943,600		19,938,268
COMMERCIAL SERVICES & SUPPLIES — 1.0%
Stericycle, Inc.(1)		463,500		42,308,280
COMMUNICATIONS EQUIPMENT — 1.9%
Aruba Networks, Inc.(1)		653,600		23,483,848
F5 Networks, Inc.(1)		355,900		36,074,024
Polycom, Inc.(1)		371,600		22,232,828
				81,790,700
COMPUTERS & PERIPHERALS — 1.8%
Apple, Inc.(1)		221,927		77,281,639
CONSTRUCTION & ENGINEERING — 1.1%
Foster Wheeler AG(1)		692,500		24,632,225
KBR, Inc.		607,400		23,305,938
				47,938,163
CONSUMER FINANCE — 0.8%
Discover Financial Services		1,359,404		33,767,595
CONTAINERS & PACKAGING — 1.4%
Crown Holdings, Inc.(1)		1,045,100		39,086,740
Rock-Tenn Co., Class A		294,700		20,354,929
				59,441,669
DIVERSIFIED CONSUMER SERVICES — 0.6%
Weight Watchers International, Inc.		334,566		26,012,507
ELECTRICAL EQUIPMENT — 2.9%
Cooper Industries plc		743,300		49,020,635
Polypore International, Inc.(1)		361,859		22,352,030
Rockwell Automation, Inc.		596,900		52,007,897
				123,380,562
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 2.0%
Jabil Circuit, Inc.		2,225,800		44,159,872
Trimble Navigation Ltd.(1)		853,700		39,987,308
				84,147,180
ENERGY EQUIPMENT & SERVICES — 4.3%
Atwood Oceanics, Inc.(1)		482,700		21,687,711
Dril-Quip, Inc.(1)		288,900		22,118,184
FMC Technologies, Inc.(1)		763,600		35,492,128
McDermott International, Inc.(1)		1,374,400		31,734,896
National Oilwell Varco, Inc.		943,300		72,341,677
				183,374,596
FOOD & STAPLES RETAILING — 2.6%
Costco Wholesale Corp.		358,000		28,969,360
Whole Foods Market, Inc.		1,316,600		82,629,816
				111,599,176
FOOD PRODUCTS — 1.6%
J.M. Smucker Co. (The)		327,500		24,585,425
Mead Johnson Nutrition Co.		616,100		41,204,768
				65,790,193
GAS UTILITIES — 0.6%
National Fuel Gas Co.		361,100		26,468,630
HEALTH CARE EQUIPMENT & SUPPLIES — 3.9%
C.R. Bard, Inc.		543,900		58,061,325
Cooper Cos., Inc. (The)		276,688		20,723,931
Mettler-Toledo International, Inc.(1)		182,200		34,144,280
Varian Medical Systems, Inc.(1)		747,900		52,502,580
				165,432,116
HEALTH CARE PROVIDERS & SERVICES — 1.1%
Express Scripts, Inc.(1)		854,500		48,484,330
HEALTH CARE TECHNOLOGY — 2.8%
Allscripts Healthcare Solutions, Inc.(1)		1,534,800		33,059,592
SXC Health Solutions Corp.(1)		1,533,577		84,592,107
				117,651,699

9

Shares Value

HOTELS, RESTAURANTS & LEISURE — 4.3%
Arcos Dorados Holdings, Inc., Class A(1)	672,855	$	14,822,996
Chipotle Mexican Grill, Inc.(1)	170,700		45,541,053
Panera Bread Co., Class A(1)	246,772		29,886,557
Royal Caribbean Cruises Ltd.(1)	2,271,500		90,451,130
			180,701,736
HOUSEHOLD DURABLES — 0.1%
KB Home	409,500		4,836,195
HOUSEHOLD PRODUCTS — 0.8%
Church & Dwight Co., Inc.	408,700		33,709,576
INTERNET & CATALOG RETAIL — 5.0%
Netflix, Inc.(1)	505,400		117,591,418
priceline.com, Inc.(1)	171,711		93,927,634
			211,519,052
INTERNET SOFTWARE & SERVICES — 4.5%
Baidu, Inc. ADR(1)	281,100		41,748,972
OpenTable, Inc.(1)	246,400		27,421,856
SAVVIS, Inc.(1)	607,700		23,919,072
VeriSign, Inc.	2,097,000		77,505,120
WebMD Health Corp.(1)	332,489		19,241,139
			189,836,159
IT SERVICES — 2.9%
Alliance Data Systems Corp.(1)	395,100		37,534,500
Cognizant Technology Solutions Corp., Class A(1)	791,800		65,640,220
VeriFone Systems, Inc.(1)	392,400		21,511,368
			124,686,088
LEISURE EQUIPMENT & PRODUCTS — 0.5%
Brunswick Corp.	869,200		20,313,204
LIFE SCIENCES TOOLS & SERVICES — 2.1%
Agilent Technologies, Inc.(1)	681,700		34,023,647
Illumina, Inc.(1)	749,300		53,185,314
			87,208,961
MACHINERY — 7.4%
AGCO Corp.(1)	950,000		54,701,000
Chart Industries, Inc.(1)	456,800		22,205,048
Cummins, Inc.	521,900		62,721,942
Deere & Co.	175,400		17,101,500
Harsco Corp.	553,778		19,714,497
Joy Global, Inc.	482,400		48,698,280
Manitowoc Co., Inc. (The)	1,270,600		28,194,614
Titan International, Inc.	755,000		23,321,950
WABCO Holdings, Inc.(1)	530,600		39,184,810
			315,843,641
MEDIA — 1.7%
Focus Media Holding Ltd. ADR(1)	232,738		8,180,741
Imax Corp.(1)	1,821,438		63,896,045
			72,076,786
METALS & MINING — 0.8%
Cliffs Natural Resources, Inc.	377,800		35,407,416
OIL, GAS & CONSUMABLE FUELS — 3.3%
Concho Resources, Inc.(1)	628,200		67,123,170
Linn Energy LLC	627,700		25,346,526
Pioneer Natural Resources Co.	158,700		16,223,901
SandRidge Energy, Inc.(1)	2,667,000		32,964,120
			141,657,717
PHARMACEUTICALS — 0.7%
Shire plc ADR	322,700		30,078,867
REAL ESTATE MANAGEMENT & DEVELOPMENT — 2.0%
CB Richard Ellis Group, Inc., Class A(1)	2,383,400		63,660,614
Jones Lang LaSalle, Inc.	215,400		22,052,652
			85,713,266
ROAD & RAIL — 1.3%
J.B. Hunt Transport Services, Inc.	478,200		22,800,576
Kansas City Southern(1)	540,600		31,414,266
			54,214,842
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 4.2%
ARM Holdings plc	2,614,500		27,284,775
Cavium Networks, Inc.(1)	971,300		45,864,786
Cypress Semiconductor Corp.(1)	1,934,300		42,090,368
OmniVision Technologies, Inc.(1)	628,300		21,110,880
Skyworks Solutions, Inc.(1)	732,000		23,028,720
Veeco Instruments, Inc.(1)	388,400		19,858,892
			179,238,421
SOFTWARE — 3.3%
Check Point Software Technologies Ltd.(1)	419,500		23,043,135
Citrix Systems, Inc.(1)	582,692		49,144,243
salesforce.com, inc.(1)	485,000		67,221,000
			139,408,378
SPECIALTY RETAIL — 4.4%
Dick’s Sporting Goods, Inc.(1)	396,171		16,215,279
O’Reilly Automotive, Inc.(1)	1,283,300		75,791,698
PetSmart, Inc.	1,204,200		50,781,114
Williams-Sonoma, Inc.	995,800		43,227,678
			186,015,769

10

Shares Value

TEXTILES, APPAREL & LUXURY GOODS — 2.1%
Fossil, Inc.(1)	436,600	$	41,817,548
Lululemon Athletica, Inc.(1)	464,600		46,473,938
			88,291,486
TRADING COMPANIES & DISTRIBUTORS — 2.0%
Fastenal Co.	921,100		61,796,599
WESCO International, Inc.(1)	378,900		23,472,855
			85,269,454
WIRELESS TELECOMMUNICATION SERVICES — 2.1%
NII Holdings, Inc.(1)	754,000		31,351,320
SBA Communications Corp., Class A(1)	1,541,832		59,560,970
			90,912,290
TOTAL COMMON STOCKS (Cost $2,985,828,582)			4,190,325,204
Temporary Cash Investments — 1.3%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	69,585		69,585
Repurchase Agreement, Credit Suisse First Boston, Inc., (collateralized by various U.S. Treasury obligations, 1.375%, 5/15/13, valued at $56,508,029), in a joint trading account at 0.01%, dated 4/29/11, due 5/2/11 (Delivery value $55,400,046)			55,400,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $55,469,585)			55,469,585
TOTAL INVESTMENT SECURITIES — 100.1% (Cost $3,041,298,167)			4,245,794,789
OTHER ASSETS AND LIABILITIES — (0.1)%			(2,940,881	)
TOTAL NET ASSETS — 100.0%		$	4,242,853,908

Forward Foreign Currency Exchange Contracts
Contracts to Sell		Counterparty	Settlement Date	Value	Unrealized Gain (Loss)
12,265,273	GBP for USD	Bank of America	5/31/11	$20,480,430	$(280,398)

(Value on Settlement Date $20,200,032)

Notes to Schedule of Investments

ADR = American Depositary Receipt

GBP = British Pound

USD = United States Dollar

(1) Non-income producing.

See Notes to Financial Statements.

11

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $3,041,298,167)	$	4,245,794,789
Receivable for investments sold		57,368,346
Receivable for capital shares sold		15,192,630
Dividends and interest receivable		701,497
		4,319,057,262
Liabilities
Payable for investments purchased		67,684,593
Payable for capital shares redeemed		4,664,823
Unrealized loss on forward foreign currency exchange contracts		280,398
Accrued management fees		3,240,045
Distribution and service fees payable		333,495
		76,203,354
Net Assets	$	4,242,853,908
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	3,103,371,548
Accumulated net investment loss		(8,397,791	)
Accumulated net realized loss		(56,337,575	)
Net unrealized appreciation		1,204,217,726
	$	4,242,853,908

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$2,804,166,420	121,163,737	$23.14
Institutional Class, $0.01 Par Value	$175,556,710	7,419,543	$23.66
A Class, $0.01 Par Value	$1,100,754,634	48,903,901	$22.51*
B Class, $0.01 Par Value	$4,643,539	205,865	$22.56
C Class, $0.01 Par Value	$125,636,351	5,971,274	$21.04
R Class, $0.01 Par Value	$32,096,254	1,404,829	$22.85

*Maximum offering price $23.88 (net asset value divided by 0.9425)

See Notes to Financial Statements.

12

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $4,459)	$	10,501,416
Interest		19,475
		10,520,891
Expenses:
Management fees		17,303,363
Distribution and service fees:
A Class		1,194,274
B Class		21,947
C Class		524,330
R Class		60,791
Directors’ fees and expenses		114,091
Other expenses		150
		19,218,946
Net investment income (loss)		(8,698,055	)
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		219,840,394
Foreign currency transactions		(733,521	)
		219,106,873
Change in net unrealized appreciation (depreciation) on:
Investments		429,040,014
Translation of assets and liabilities in foreign currencies		21,324
		429,061,338
Net realized and unrealized gain (loss)		648,168,211
Net Increase (Decrease) in Net Assets Resulting from Operations	$	639,470,156

See Notes to Financial Statements.

13

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	(8,698,055	)	$	(13,068,160	)
Net realized gain (loss)		219,106,873			209,252,754
Change in net unrealized appreciation (depreciation)		429,061,338			502,214,585
Net increase (decrease) in net assets resulting from operations		639,470,156			698,399,179
Distributions to Shareholders
From net investment income:
Institutional Class		—			(45,786	)
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		690,779,448			200,776,280
Net increase (decrease) in net assets		1,330,249,604			899,129,673
Net Assets
Beginning of period		2,912,604,304			2,013,474,631
End of period	$	4,242,853,908		$	2,912,604,304
Accumulated undistributed net investment income (loss)	$	(8,397,791	)	$	300,264

See Notes to Financial Statements.

14

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Heritage Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing in companies that are medium-sized and smaller at the time of purchase that management believes will increase in value over time.

The fund is authorized to issue the Investor Class, the Institutional Class, the A Class, the B Class, the C Class and the R Class. The A Class may incur an initial sales charge. The A Class, B Class and C Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Forward foreign currency exchange contracts are valued at the mean of the latest bid and asked prices of the forward currency rates as provided by an independent pricing service.

15

The value of investments initially expressed in foreign currencies is translated into U.S. dollars at prevailing exchange rates.

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Foreign Currency Translations — All assets and liabilities initially expressed in foreign currencies are translated into U.S. dollars at prevailing exchange rates at period end. The fund may enter into spot foreign currency exchange contracts to facilitate transactions denominated in a foreign currency. Purchases and sales of investment securities, dividend and interest income, spot foreign currency exchange contracts, and expenses are translated at the rates of exchange prevailing on the respective dates of such transactions. Net realized and unrealized foreign currency exchange gains or losses related to investment securities are a component of net realized gain (loss) on investment transactions and change in net unrealized appreciation (depreciation) on investments, respectively.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. Additionally, non-U.S. tax returns filed by the fund due to investments in certain foreign securities remain subject to examination by the relevant taxing authority for seven years from the date of the filing. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

16

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The annual management fee is 1.000% for the Investor Class, A Class, B Class, C Class and R Class and 0.800% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a separate Master Distribution and Individual Shareholder Services Plan for each of the A Class, B Class, C Class and R Class (collectively the plans), pursuant to Rule 12b-1 of the 1940 Act. The plans provide that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The plans provide that the B Class and C Class will each pay ACIS an annual distribution and service fee of 1.00%, of which 0.25% is paid for individual shareholder services and 0.75% is paid for distribution services. The plans provide that the R Class will pay ACIS an annual distribution and service fee of 0.50%.The fees are computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services. Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMorgan Chase Bank (JPMCB) is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $2,141,773,992 and $1,441,869,260, respectively.

17

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		400,000,000						400,000,000
Sold		34,644,676		$	753,803,344			24,446,309		$	416,217,265
Redeemed		(11,715,911	)		(251,687,637	)		(19,973,254	)		(330,354,418	)
		22,928,765			502,115,707			4,473,055			85,862,847
Institutional Class/Shares Authorized		40,000,000						40,000,000
Sold		2,378,642			51,530,923			1,592,345			27,658,160
Issued in reinvestment of distributions		—			—			2,804			45,786
Redeemed		(834,797	)		(18,522,417	)		(2,044,059	)		(34,815,396	)
		1,543,845			33,008,506			(448,910	)		(7,111,450	)
A Class/Shares Authorized		200,000,000						200,000,000
Sold		12,149,331			253,507,145			16,547,628			270,449,421
Redeemed		(6,217,689	)		(129,705,449	)		(10,692,346	)		(173,010,082	)
		5,931,642			123,801,696			5,855,282			97,439,339
B Class/Shares Authorized		35,000,000						35,000,000
Sold		11,358			234,275			17,058			265,517
Redeemed		(17,969	)		(377,224	)		(46,411	)		(756,266	)
		(6,611	)		(142,949	)		(29,353	)		(490,749	)
C Class/Shares Authorized		35,000,000						35,000,000
Sold		1,670,795			32,789,808			2,174,035			33,791,342
Redeemed		(565,270	)		(11,054,706	)		(1,225,116	)		(18,799,544	)
		1,105,525			21,735,102			948,919			14,991,798
R Class/Shares Authorized		30,000,000						30,000,000
Sold		695,681			14,835,970			873,774			14,881,532
Redeemed		(213,891	)		(4,574,584	)		(286,027	)		(4,797,037	)
		481,790			10,261,386			587,747			10,084,495
Net increase (decrease)		31,984,956		$	690,779,448			11,386,740		$	200,776,280

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

18

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2			Level 3
Investment Securities
Domestic Common Stocks	$	3,781,808,003		—			—
Foreign Common Stocks		381,232,426	$	27,284,775			—
Temporary Cash Investments		69,585		55,400,000			—
Total Value of Investment Securities	$	4,163,110,014	$	82,684,775			—
Other Financial Instruments
Total Unrealized Gain (Loss) on Forward Foreign Currency Exchange Contracts		—	$	(280,398	)		—

7. Derivative Instruments

Foreign Currency Risk — The fund is subject to foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The value of foreign investments held by a fund may be significantly affected by changes in foreign currency exchange rates. The dollar value of a foreign security generally decreases when the value of the dollar rises against the foreign currency in which the security is denominated and tends to increase when the value of the dollar declines against such foreign currency. A fund may enter into forward foreign currency exchange contracts to reduce a fund’s exposure to foreign currency exchange rate fluctuations. The net U.S. dollar value of foreign currency underlying all contractual commitments held by a fund and the resulting unrealized appreciation or depreciation are determined daily. Realized gain or loss is recorded upon the termination of the contract. Net realized and unrealized gains or losses occurring during the holding period of forward foreign currency exchange contracts are a component of net realized gain (loss) on foreign currency transactions and change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies, respectively. A fund bears the risk of an unfavorable change in the foreign currency exchange rate underlying the forward contract. Additionally, losses, up to the fair value, may arise if the counterparties do not perform under the contract terms. The risk of loss from non-performance by the counterparty may be reduced by the use of master netting agreements. The foreign currency risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

The value of foreign currency risk derivative instruments as of April 30, 2011, is disclosed on the Statement of Assets and Liabilities as a liability of $280,398 in unrealized loss on forward foreign currency exchange contracts. For the six months ended April 30, 2011, the effect of foreign currency risk derivative instruments on the Statement of Operations was $(780,600) in net realized gain (loss) on foreign currency transactions and $19,866 in change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies.

8. Risk Factors

There are certain risks involved in investing in foreign securities. These risks include those resulting from future adverse political, social, and economic developments, fluctuations in currency exchange rates, the possible imposition of exchange controls, and other foreign laws or restrictions.

19

9. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	3,045,631,694
Gross tax appreciation of investments	$	1,207,668,786
Gross tax depreciation of investments		(7,505,691	)
Net tax appreciation (depreciation) of investments	$	1,200,163,095

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(274,256,289), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers expire in 2017.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

20

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	19.21		$	14.32		$	13.15		$	22.83		$	15.58		$	13.48
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.04	)		(0.07	)		(0.02	)		(0.09	)		(0.10	)		(0.03	)
Net Realized and    Unrealized Gain (Loss)		3.97			4.96			1.32			(8.53	)		8.42			2.22
Total From    Investment Operations		3.93			4.89			1.30			(8.62	)		8.32			2.19
Distributions
From Net    Investment Income		—			—			(0.13	)		—			—			—
From Net Realized Gains		—			—			—			(1.06	)		(1.07	)		(0.09	)
Total Distributions		—			—			(0.13	)		(1.06	)		(1.07	)		(0.09	)
Net Asset Value, End of Period	$	23.14		$	19.21		$	14.32		$	13.15		$	22.83		$	15.58
Total Return(3)		20.46	%		34.15	%		10.16	%		(39.54	)%		56.41	%		16.26	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.01	%(4)		1.01	%		1.01	%		1.00	%		1.00	%		1.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.41	)%(4)		(0.45	)%		(0.19	)%		(0.47	)%		(0.56	)%		(0.22	)%
Portfolio Turnover Rate		41	%		114	%		155	%		172	%		128	%		230	%
Net Assets, End of Period (in millions)	$	2,804		$	1,887		$	1,342		$	1,262		$	2,478		$	1,037

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

21

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	19.62		$	14.60		$	13.41		$	23.21		$	15.80		$	13.63
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.02	)		(0.04	)		—	(3)		(0.05	)		(0.07	)		—	(3)
Net Realized and    Unrealized Gain (Loss)		4.06			5.07			1.34			(8.69	)		8.55			2.26
Total From    Investment Operations		4.04			5.03			1.34			(8.74	)		8.48			2.26
Distributions
From Net    Investment Income		—			(0.01	)		(0.15	)		—			—			—
From Net Realized Gains		—			—			—			(1.06	)		(1.07	)		(0.09	)
Total Distributions		—			(0.01	)		(0.15	)		(1.06	)		(1.07	)		(0.09	)
Net Asset Value, End of Period	$	23.66		$	19.62		$	14.60		$	13.41		$	23.21		$	15.80
Total Return(4)		20.59	%		34.44	%		10.33	%		(39.41	)%		56.66	%		16.59	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.81	%(5)		0.81	%		0.81	%		0.80	%		0.80	%		0.80	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.21	)%(5)		(0.25	)%		0.01	%		(0.27	)%		(0.36	)%		(0.02	)%
Portfolio Turnover Rate		41	%		114	%		155	%		172	%		128	%		230	%
Net Assets, End of Period (in thousands)	$	175,557		$	115,261		$	92,343		$	86,835		$	155,885		$	57,039

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Per-share amount was less than $0.005.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

22

A Class(1)
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(2)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	18.70		$	13.98		$	12.84		$	22.37		$	15.32		$	13.29
Income From Investment Operations
Net Investment    Income (Loss)(3)		(0.07	)		(0.11	)		(0.06	)		(0.13	)		(0.15	)		(0.08	)
Net Realized and    Unrealized Gain (Loss)		3.88			4.83			1.30			(8.34	)		8.27			2.20
Total From    Investment Operations		3.81			4.72			1.24			(8.47	)		8.12			2.12
Distributions
From Net    Investment Income		—			—			(0.10	)		—			—			—
From Net Realized Gains		—			—			—			(1.06	)		(1.07	)		(0.09	)
Total Distributions		—			—			(0.10	)		(1.06	)		(1.07	)		(0.09	)
Net Asset Value, End of Period	$	22.51		$	18.70		$	13.98		$	12.84		$	22.37		$	15.32
Total Return(4)		20.37	%		33.76	%		9.89	%		(39.69	)%		56.05	%		15.96	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.26	%(5)		1.26	%		1.26	%		1.25	%		1.25	%		1.25	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.66	)%(5)		(0.70	)%		(0.44	)%		(0.72	)%		(0.81	)%		(0.47	)%
Portfolio Turnover Rate		41	%		114	%		155	%		172	%		128	%		230	%
Net Assets, End of Period (in thousands)	$	1,100,755		$	803,692		$	518,768		$	351,962		$	291,674		$	57,995

(1) Prior to September 4, 2007, the A Class was referred to as the Advisor Class.

(2) Six months ended April 30, 2011 (unaudited).

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

23

B Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	18.81		$	14.16		$	13.01		$	22.82		$	21.52
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.14	)		(0.24	)		(0.16	)		(0.26	)		(0.03	)
Net Realized and Unrealized Gain (Loss)		3.89			4.89			1.33			(8.49	)		1.33
Total From Investment Operations		3.75			4.65			1.17			(8.75	)		1.30
Distributions
From Net Investment Income		—			—			(0.02	)		—			—
From Net Realized Gains		—			—			—			(1.06	)		—
Total Distributions		—			—			(0.02	)		(1.06	)		—
Net Asset Value, End of Period	$	22.56		$	18.81		$	14.16		$	13.01		$	22.82
Total Return(4)		19.88	%		32.84	%		8.99	%		(40.16	)%		6.04	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.01	%(5)		2.01	%		2.01	%		2.00	%		2.00	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(1.41	)%(5)		(1.45	)%		(1.19	)%		(1.47	)%		(1.81	)%(5)
Portfolio Turnover Rate		41	%		114	%		155	%		172	%		128	%(6)
Net Assets, End of Period (in thousands)	$	4,644		$	3,997		$	3,425		$	1,770		$	83

(1) Six months ended April 30, 2011 (unaudited).

(2) September 28, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

24

C Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	17.55		$	13.21		$	12.13		$	21.35		$	14.77		$	12.91
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.14	)		(0.22	)		(0.14	)		(0.26	)		(0.29	)		(0.18	)
Net Realized and    Unrealized Gain (Loss)		3.63			4.56			1.24			(7.90	)		7.94			2.13
Total From    Investment Operations		3.49			4.34			1.10			(8.16	)		7.65			1.95
Distributions
From Net    Investment Income		—			—			(0.02	)		—			—			—
From Net Realized Gains		—			—			—			(1.06	)		(1.07	)		(0.09	)
Total Distributions		—			—			(0.02	)		(1.06	)		(1.07	)		(0.09	)
Net Asset Value, End of Period	$	21.04		$	17.55		$	13.21		$	12.13		$	21.35		$	14.77
Total Return(3)		19.89	%		32.85	%		9.07	%		(40.16	)%		54.88	%		15.11	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.01	%(4)		2.01	%		2.01	%		2.00	%		2.00	%		2.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(1.41	)%(4)		(1.45	)%		(1.19	)%		(1.47	)%		(1.56	)%		(1.22	)%
Portfolio Turnover Rate		41	%		114	%		155	%		172	%		128	%		230	%
Net Assets, End of Period (in thousands)	$	125,636		$	85,381		$	51,745		$	32,812		$	21,692		$	2,334

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

25

R Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	19.01		$	14.24		$	13.08		$	22.83		$	21.52
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.10	)		(0.16	)		(0.11	)		(0.17	)		(0.02	)
Net Realized and Unrealized Gain (Loss)		3.94			4.93			1.34			(8.52	)		1.33
Total From Investment Operations		3.84			4.77			1.23			(8.69	)		1.31
Distributions
From Net Investment Income		—			—			(0.07	)		—			—
From Net Realized Gains		—			—			—			(1.06	)		—
Total Distributions		—			—			(0.07	)		(1.06	)		—
Net Asset Value, End of Period	$	22.85		$	19.01		$	14.24		$	13.08		$	22.83
Total Return(4)		20.20	%		33.50	%		9.58	%		(39.86	)%		6.09	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.51	%(5)		1.51	%		1.51	%		1.50	%		1.50	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.91	)%(5)		(0.95	)%		(0.69	)%		(0.97	)%		(1.22	)%(5)
Portfolio Turnover Rate		41	%		114	%		155	%		172	%		128	%(6)
Net Assets, End of Period (in thousands)	$	32,096		$	17,544		$	4,775		$	496		$	27

(1) Six months ended April 30, 2011 (unaudited).

(2) September 28, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

26

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

27

Notes

28

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71842   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

New Opportunities Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	13
Statement of Operations	14
Statement of Changes in Net Assets	15
Notes to Financial Statements	16
Financial Highlights	21
Additional Information	26

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year(2)	5 years	10 years	Since Inception	Inception Date
Investor Class	TWNOX	27.84%	33.89%	4.70%	4.33%	7.53%	12/26/96
Russell 2500 Growth Index	—	27.08%	30.07%	5.91%	6.39%	7.02%(3)	—
Institutional Class	TWNIX	27.80%	34.05%	—	—	37.30%(2)	3/1/10
A Class    No sales charge*    With sales charge*	TWNAX	27.59% 20.22%	33.44% 25.76%	— —	— —	36.76%(2)   29.99%(2)	3/1/10
C Class    No sales charge*    With sales charge*	TWNCX	27.17% 26.17%	32.42% 32.42%	— —	— —	35.69%(2)   35.69%(2)	3/1/10
R Class	TWNRX	27.34%	32.98%	—	—	36.36%(2)	3/1/10

* Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. C Class shares redeemed within 12 months of purchase are subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

(2) Extraordinary performance is attributable in part to unusually favorable market conditions and may not be repeated or consistently achieved in the future.

(3) Since 12/31/96, the date nearest the Investor Class’s inception for which data are available.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class	C Class	R Class
1.51%	1.31%	1.76%	2.51%	2.01%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. Historically, small company stocks have been more volatile than the stocks of larger, more established companies. The fund’s investment process may result in high portfolio turnover, which could mean high transaction costs, affecting both performance and capital gains tax liabilities to investors.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Tempur-Pedic International, Inc.	2.0%
Sauer-Danfoss, Inc.	1.7%
Titan International, Inc.	1.7%
Acme Packet, Inc.	1.4%
Sotheby’s	1.3%
Lindsay Corp.	1.3%
Iconix Brand Group, Inc.	1.3%
BorgWarner, Inc.	1.2%
Pioneer Drilling Co.	1.1%
United Rentals, Inc.	1.0%
Top Five Industries	% of net assets
Machinery	10.3%
Software	6.2%
Semiconductors & Semiconductor Equipment	5.0%
Oil, Gas & Consumable Fuels	4.7%
Internet Software & Services	4.3%
Types of Investments in Portfolio	% of net assets
Common Stocks	96.6%
Temporary Cash Investments	3.0%
Other Assets and Liabilities	0.4%

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,278.40	$8.47	1.50%
Institutional Class	$1,000	$1,278.00	$7.34	1.30%
A Class	$1,000	$1,275.90	$9.88	1.75%
C Class	$1,000	$1,271.70	$14.08	2.50%
R Class	$1,000	$1,273.40	$11.27	2.00%
Hypothetical
Investor Class	$1,000	$1,017.36	$7.50	1.50%
Institutional Class	$1,000	$1,018.35	$6.51	1.30%
A Class	$1,000	$1,016.12	$8.75	1.75%
C Class	$1,000	$1,012.40	$12.47	2.50%
R Class	$1,000	$1,014.88	$9.99	2.00%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 96.6%
AEROSPACE & DEFENSE — 1.2%
BE Aerospace, Inc.(1)		5,862	$	226,214
TransDigm Group, Inc.(1)		6,899		574,687
Triumph Group, Inc.		17,034		1,466,968
				2,267,869
AIRLINES — 0.2%
United Continental Holdings, Inc.(1)		19,307		440,586
AUTO COMPONENTS — 2.3%
American Axle & Manufacturing Holdings, Inc.(1)		103,021		1,318,669
Amerigon, Inc.(1)		11,287		192,443
BorgWarner, Inc.(1)		29,005		2,240,346
Goodyear Tire & Rubber Co. (The)(1)		36,907		669,862
				4,421,320
BIOTECHNOLOGY — 2.8%
Acorda Therapeutics, Inc.(1)		5,998		168,184
Alexion Pharmaceuticals, Inc.(1)		11,920		1,154,929
Amylin Pharmaceuticals, Inc.(1)		19,533		259,789
BioMarin Pharmaceutical, Inc.(1)		13,569		364,870
Cepheid, Inc.(1)		8,725		281,905
Cubist Pharmaceuticals, Inc.(1)		8,416		284,882
Human Genome Sciences, Inc.(1)		25,867		762,300
Incyte Corp. Ltd.(1)		11,403		210,727
Isis Pharmaceuticals, Inc.(1)		14,142		132,652
Onyx Pharmaceuticals, Inc.(1)		8,489		318,932
Regeneron Pharmaceuticals, Inc.(1)		9,839		502,871
Seattle Genetics, Inc.(1)		13,937		231,494
Theravance, Inc.(1)		8,928		247,752
United Therapeutics Corp.(1)		6,913		462,894
				5,384,181
CAPITAL MARKETS — 1.0%
BGC Partners, Inc., Class A		44,437		428,817
Eaton Vance Corp.		14,242		480,953
Lazard Ltd., Class A		11,834		485,194
SEI Investments Co.		18,137		404,999
				1,799,963
CHEMICALS — 3.3%
Albemarle Corp.		19,532		1,377,983
Balchem Corp.		15,741		624,760
Flotek Industries, Inc.(1)		36,985		354,316
International Flavors & Fragrances, Inc.		10,741		682,268
Intrepid Potash, Inc.(1)		38,743		1,327,335
Nalco Holding Co.		13,361		390,275
OM Group, Inc.(1)		530		19,207
Solutia, Inc.(1)		54,801		1,444,007
				6,220,151
COMMERCIAL BANKS — 1.8%
Cathay General Bancorp.		60,299		1,028,098
Nara Bancorp., Inc.(1)		46,718		459,238
Pinnacle Financial Partners, Inc.(1)		34,637		556,616
PrivateBancorp, Inc.		26,442		416,197
Sandy Spring Bancorp, Inc.		5,416		96,784
Texas Capital Bancshares, Inc.(1)		20,769		535,840
West Coast Bancorp.(1)		96,370		345,005
				3,437,778
COMMERCIAL SERVICES & SUPPLIES — 0.9%
Deluxe Corp.		20,016		542,033
Steelcase, Inc., Class A		60,422		697,874
Team, Inc.(1)		19,574		488,372
				1,728,279
COMMUNICATIONS EQUIPMENT — 3.3%
Acme Packet, Inc.(1)		32,903		2,718,117
F5 Networks, Inc.(1)		3,110		315,229
Finisar Corp.(1)		8,141		228,681
JDS Uniphase Corp.(1)		24,702		514,790
Netgear, Inc.(1)		18,022		752,418
Oplink Communications, Inc.(1)		41,137		814,513
Opnext, Inc.(1)		63,802		150,573
Riverbed Technology, Inc.(1)		20,721		728,136
Sycamore Networks, Inc.		3,129		76,660
				6,299,117
COMPUTERS & PERIPHERALS — 0.7%
Avid Technology, Inc.(1)		16,332		303,449
Stratasys, Inc.(1)		8,231		443,239
USA Technologies, Inc.(1)		190,675		579,652
				1,326,340

8

	Shares		Value
CONSTRUCTION MATERIALS — 0.5%
Headwaters, Inc.(1)	71,847	$	392,285
Martin Marietta Materials, Inc.	5,624		512,852
			905,137
CONSUMER FINANCE — 1.1%
EZCORP, Inc., Class A(1)	26,191		824,755
World Acceptance Corp.(1)	18,520		1,258,434
			2,083,189
CONTAINERS & PACKAGING — 0.4%
Crown Holdings, Inc.(1)	20,138		753,161
DIVERSIFIED CONSUMER SERVICES — 2.0%
DeVry, Inc.	5,243		277,355
ITT Educational Services, Inc.(1)	2,274		163,114
K12, Inc.(1)	5,809		228,700
Sotheby’s	48,750		2,462,850
Steiner Leisure, Ltd.(1)	12,728		617,817
			3,749,836
DIVERSIFIED FINANCIAL SERVICES — 0.4%
Encore Capital Group, Inc.(1)	11,052		330,897
MSCI, Inc., Class A(1)	14,241		505,128
			836,025
DIVERSIFIED TELECOMMUNICATION SERVICES — 0.2%
Vonage Holdings Corp.(1)	80,193		413,796
ELECTRICAL EQUIPMENT — 0.7%
AMETEK, Inc.	21,047		969,004
Franklin Electric Co., Inc.	4,090		184,500
Valence Technology, Inc.(1)	54,163		73,662
			1,227,166
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 3.9%
Cognex Corp.	38,168		1,193,895
FARO Technologies, Inc.(1)	4,868		210,152
FLIR Systems, Inc.	15,537		547,213
KEMET Corp.(1)	85,333		1,342,288
Littelfuse, Inc.	30,007		1,866,735
Measurement Specialties, Inc.(1)	7,815		271,806
MTS Systems Corp.	5,301		234,675
Trimble Navigation Ltd.(1)	29,714		1,391,804
TTM Technologies, Inc.(1)	17,172		328,329
			7,386,897
ENERGY EQUIPMENT & SERVICES — 3.6%
Basic Energy Services, Inc.(1)	51,229		1,574,779
Complete Production Services, Inc.(1)	39,417		1,337,813
Core Laboratories NV	6,076		583,174
Dawson Geophysical Co.(1)	7,166		319,604
Hornbeck Offshore Services, Inc.(1)	10,292		300,835
Matrix Service Co.(1)	33,860		489,616
North American Energy Partners, Inc.(1)	6,564		74,830
OYO Geospace Corp.(1)	1,792		167,158
Pioneer Drilling Co.(1)	132,971		2,061,050
			6,908,859
FOOD & STAPLES RETAILING — 1.6%
Andersons, Inc. (The)	31,141		1,546,150
PriceSmart, Inc.	34,595		1,440,536
			2,986,686
FOOD PRODUCTS — 0.3%
B&G Foods, Inc.	33,781		610,761
HEALTH CARE EQUIPMENT & SUPPLIES — 3.0%
Align Technology, Inc.(1)	8,648		208,763
American Medical Systems Holdings, Inc.(1)	9,950		293,525
Gen-Probe, Inc.(1)	6,963		577,372
Haemonetics Corp.(1)	3,317		232,853
IDEXX Laboratories, Inc.(1)	7,868		640,691
Immucor, Inc.(1)	10,461		228,364
Integra LifeSciences Holdings Corp.(1)	3,238		169,380
Masimo Corp.	8,110		282,147
Mettler-Toledo International, Inc.(1)	4,620		865,788
NuVasive, Inc.(1)	6,683		206,438
ResMed, Inc.(1)	20,972		668,797
Sirona Dental Systems, Inc.(1)	5,082		290,030
STERIS Corp.	7,602		273,976
Thoratec Corp.(1)	7,605		233,473
Volcano Corp.(1)	7,813		208,295
West Pharmaceutical Services, Inc.	4,767		225,193
			5,605,085
HEALTH CARE PROVIDERS & SERVICES — 2.3%
Amedisys, Inc.(1)	4,495		149,773
Catalyst Health Solutions, Inc.(1)	5,348		318,527
Chemed Corp.	3,258		226,855
Community Health Systems, Inc.(1)	9,178		282,040
Emergency Medical Services Corp., Class A(1)	3,992		254,690
Health Management Associates, Inc., Class A(1)	34,084		384,467
HealthSouth Corp.(1)	12,799		328,038

9

Shares Value

HMS Holdings Corp.(1)	3,643	$	286,741
Lincare Holdings, Inc.	13,758		432,276
Mednax, Inc.(1)	6,167		437,364
Owens & Minor, Inc.	7,161		246,696
Patterson Cos., Inc.	14,327		497,290
PSS World Medical, Inc.(1)	8,517		244,949
Tenet Healthcare Corp.(1)	46,421		321,698
			4,411,404
HEALTH CARE TECHNOLOGY — 0.8%
Allscripts Healthcare Solutions, Inc.(1)	16,896		363,940
athenahealth, Inc.(1)	4,984		230,410
MedAssets, Inc.(1)	7,054		113,005
Quality Systems, Inc.	2,722		244,218
SXC Health Solutions Corp.(1)	8,505		469,136
			1,420,709
HOTELS, RESTAURANTS & LEISURE — 0.5%
Chipotle Mexican Grill, Inc.(1)	3,276		874,004
HOUSEHOLD DURABLES — 2.3%
NVR, Inc.(1)	627		463,560
Tempur-Pedic International, Inc.(1)	61,190		3,841,508
			4,305,068
INDUSTRIAL CONGLOMERATES — 0.8%
Raven Industries, Inc.	27,535		1,496,803
INSURANCE — 0.5%
AMERISAFE, Inc.(1)	24,754		552,757
Amtrust Financial Services, Inc.	19,534		377,006
			929,763
INTERNET & CATALOG RETAIL — 0.9%
Netflix, Inc.(1)	1,070		248,957
priceline.com, Inc.(1)	2,031		1,110,977
Shutterfly, Inc.(1)	5,685		349,969
			1,709,903
INTERNET SOFTWARE & SERVICES — 4.3%
Ancestry.com, Inc.(1)	19,735		901,889
Dice Holdings, Inc.(1)	94,492		1,732,038
Equinix, Inc.(1)	6,024		606,376
Keynote Systems, Inc.	41,511		885,845
KIT Digital, Inc.(1)	4,724		54,373
Rackspace Hosting, Inc.(1)	15,206		702,365
Travelzoo, Inc.(1)	11,383		932,268
ValueClick, Inc.(1)	44,813		750,618
Vocus, Inc.(1)	42,919		1,271,690
WebMD Health Corp.(1)	6,545		378,759
			8,216,221
IT SERVICES — 0.7%
Alliance Data Systems Corp.(1)	7,561		718,295
Global Payments, Inc.	10,327		549,809
MAXIMUS, Inc.	1,644		131,504
			1,399,608
LEISURE EQUIPMENT & PRODUCTS — 1.0%
Polaris Industries, Inc.	17,438		1,838,488
LIFE SCIENCES TOOLS & SERVICES — 1.1%
Bruker Corp.(1)	11,086		218,838
Covance, Inc.(1)	8,501		532,162
Dionex Corp.(1)	2,479		293,390
PAREXEL International Corp.(1)	8,170		226,799
Pharmaceutical Product Development, Inc.	14,340		442,389
TECHNE Corp.	5,072		394,145
			2,107,723
MACHINERY — 10.3%
3D Systems Corp.(1)	10,304		429,883
AGCO Corp.(1)	19,571		1,126,898
Blount International, Inc.(1)	25,397		421,590
Cascade Corp.	15,653		716,907
CIRCOR International, Inc.	3,388		153,917
Donaldson Co., Inc.	9,763		597,788
EnPro Industries, Inc.(1)	8,009		321,001
Graham Corp.	6,361		145,540
Kadant, Inc.(1)	11,375		350,919
Lindsay Corp.	33,555		2,460,253
Manitowoc Co., Inc. (The)	33,490		743,143
Middleby Corp.(1)	11,824		1,060,258
NACCO Industries, Inc., Class A	3,428		360,728
Navistar International Corp.(1)	9,577		665,793
Pall Corp.	18,974		1,108,840
Robbins & Myers, Inc.	33,089		1,438,379
Sauer-Danfoss, Inc.(1)	55,757		3,290,220
Titan International, Inc.	104,194		3,218,553
Twin Disc, Inc.	8,653		294,808
Wabash National Corp.(1)	55,357		610,588
			19,516,006
MEDIA — 1.8%
Interpublic Group of Cos., Inc. (The)	82,450		968,788
MDC Partners, Inc., Class A	43,215		718,666
Sinclair Broadcast Group, Inc., Class A	76,523		879,249
Sirius XM Radio, Inc.(1)	455,276		905,999
			3,472,702

10

Shares Value

METALS & MINING — 3.0%
Allied Nevada Gold Corp.(1)	30,226	$	1,301,532
Compass Minerals International, Inc.	10,640		1,038,570
Globe Specialty Metals, Inc.	60,730		1,367,032
Materion Corp.(1)	27,106		1,131,947
Walter Energy, Inc.	5,824		804,993
			5,644,074
OIL, GAS & CONSUMABLE FUELS — 4.7%
Alpha Natural Resources, Inc.(1)	15,381		894,713
Concho Resources, Inc.(1)	13,972		1,492,908
Crosstex Energy LP	48,313		954,665
Forest Oil Corp.(1)	11,093		398,350
Goodrich Petroleum Corp.(1)	31,214		701,379
Gulfport Energy Corp.(1)	34,957		1,189,936
Stone Energy Corp.(1)	33,159		1,172,502
W&T Offshore, Inc.	20,405		547,058
Western Refining, Inc.(1)	90,092		1,527,960
			8,879,471
PAPER & FOREST PRODUCTS — 0.3%
Buckeye Technologies, Inc.	21,433		603,553
PHARMACEUTICALS — 0.4%
Auxilium Pharmaceuticals, Inc.(1)	6,242		152,055
Impax Laboratories, Inc.(1)	7,803		213,646
Nektar Therapeutics(1)	16,406		170,294
Salix Pharmaceuticals Ltd.(1)	7,702		302,612
			838,607
PROFESSIONAL SERVICES — 1.1%
Kelly Services, Inc., Class A(1)	73,369		1,402,082
Robert Half International, Inc.	25,080		760,676
			2,162,758
REAL ESTATE INVESTMENT TRUSTS (REITs) — 1.5%
Ashford Hospitality Trust, Inc.	38,538		480,569
Digital Realty Trust, Inc.	9,942		599,900
Lexington Realty Trust	19,363		193,243
Medical Properties Trust, Inc.	39,899		492,354
Post Properties, Inc.	27,029		1,097,377
			2,863,443
REAL ESTATE MANAGEMENT & DEVELOPMENT — 1.1%
CB Richard Ellis Group, Inc., Class A(1)	50,383		1,345,730
Jones Lang LaSalle, Inc.	6,591		674,787
			2,020,517
ROAD & RAIL — 0.5%
Kansas City Southern(1)	14,614		849,220
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 5.0%
Atmel Corp.(1)	72,448		1,108,454
Cavium Networks, Inc.(1)	9,570		451,895
CEVA, Inc.(1)	22,573		690,282
Cirrus Logic, Inc.(1)	9,751		161,477
Cypress Semiconductor Corp.(1)	28,877		628,363
Entegris, Inc.(1)	89,904		775,871
GSI Technology, Inc.(1)	32,403		288,711
GT Solar International, Inc.(1)	69,500		776,315
ON Semiconductor Corp.(1)	68,137		716,120
Photronics, Inc.(1)	88,442		772,099
RF Micro Devices, Inc.(1)	28,107		187,193
Silicon Image, Inc.(1)	38,563		320,844
Skyworks Solutions, Inc.(1)	39,219		1,233,830
Ultratech, Inc.(1)	42,283		1,323,881
Veeco Instruments, Inc.(1)	1,090		55,732
			9,491,067
SOFTWARE — 6.2%
ACI Worldwide, Inc.(1)	20,721		684,622
Allot Communications Ltd.(1)	22,897		374,366
ANSYS, Inc.(1)	11,865		656,016
Ariba, Inc.(1)	11,343		394,396
Callidus Software, Inc.(1)	27,069		187,047
DemandTec, Inc.(1)	29,927		331,292
FactSet Research Systems, Inc.	5,082		556,022
Fortinet, Inc.(1)	9,378		456,708
Informatica Corp.(1)	10,822		606,140
Interactive Intelligence, Inc.(1)	23,578		882,289
Kenexa Corp.(1)	64,386		1,894,236
Motricity, Inc.(1)	14,303		191,088
Nuance Communications, Inc.(1)	29,189		604,212
Opnet Technologies, Inc.	15,060		589,750
Progress Software Corp.(1)	12,713		376,940
PROS Holdings, Inc.(1)	26,253		411,647
Rovi Corp.(1)	7,964		386,732
Taleo Corp., Class A(1)	9,852		357,332
TIBCO Software, Inc.(1)	25,367		760,756
VASCO Data Security International, Inc.(1)	62,799		774,940
Websense, Inc.(1)	8,903		229,608
			11,706,139

11

Shares Value

SPECIALTY RETAIL — 3.0%
CarMax, Inc.(1)	32,890	$	1,141,283
Charming Shoppes, Inc.(1)	103,235		467,655
Lithia Motors, Inc., Class A	90,528		1,646,704
PetSmart, Inc.	16,279		686,485
Tractor Supply Co.	25,504		1,577,933
Williams-Sonoma, Inc.	5,576		242,054
			5,762,114
TEXTILES, APPAREL & LUXURY GOODS — 3.4%
Crocs, Inc.(1)	24,735		497,421
Deckers Outdoor Corp.(1)	15,186		1,288,684
G-III Apparel Group Ltd.(1)	29,181		1,309,060
Iconix Brand Group, Inc.(1)	98,078		2,401,930
Lululemon Athletica, Inc.(1)	1,252		125,237
Oxford Industries, Inc.	19,717		677,279
Perry Ellis International, Inc.(1)	3,629		102,265
			6,401,876
TRADING COMPANIES & DISTRIBUTORS — 3.3%
CAI International, Inc.(1)	40,341		1,014,980
H&E Equipment Services, Inc.(1)	27,468		546,613
RSC Holdings, Inc.(1)	31,345		412,814
Rush Enterprises, Inc., Class A(1)	30,113		634,481
Titan Machinery, Inc.(1)	52,446		1,649,951
United Rentals, Inc.(1)	67,543		1,987,115
			6,245,954
WIRELESS TELECOMMUNICATION SERVICES — 0.6%
MetroPCS Communications, Inc.(1)	35,823		602,901
SBA Communications Corp., Class A(1)	14,621		564,809
			1,167,710
TOTAL COMMON STOCKS (Cost $134,279,587)			183,127,087

	Principal Amount/Shares		Value
Temporary Cash Investments — 3.0%
FHLB Discount Notes, 0.001%, 5/2/11(2)	$	5,600,000	$	5,600,000
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares		79,734		79,734
TOTAL TEMPORARY CASH INVESTMENTS (Cost $5,679,734)				5,679,734
TOTAL INVESTMENT SECURITIES — 99.6% (Cost $139,959,321)				188,806,821
OTHER ASSETS AND LIABILITIES — 0.4%				844,459
TOTAL NET ASSETS — 100.0%			$	189,651,280

Notes to Schedule of Investments

FHLB = Federal Home Loan Bank

(1) Non-income producing.

(2) The rate indicated is the yield to maturity at purchase.

See Notes to Financial Statements.

12

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $139,959,321)	$	188,806,821
Receivable for investments sold		4,651,441
Receivable for capital shares sold		112,651
Dividends and interest receivable		39,984
		193,610,897
Liabilities
Payable for investments purchased		3,714,563
Payable for capital shares redeemed		20,000
Accrued management fees		224,948
Distribution and service fees payable		106
		3,959,617
Net Assets	$	189,651,280
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	192,308,584
Accumulated net investment loss		(768,307	)
Accumulated net realized loss		(50,736,497	)
Net unrealized appreciation		48,847,500
	$	189,651,280

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$189,280,142	21,591,388	$8.77
Institutional Class, $0.01 Par Value	$36,178	4,119	$8.78
A Class, $0.01 Par Value	$237,715	27,196	$8.74*
C Class, $0.01 Par Value	$59,402	6,857	$8.66
R Class, $0.01 Par Value	$37,843	4,344	$8.71

*Maximum offering price $9.27 (net asset value divided by 0.9425)

See Notes to Financial Statements.

13

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $1,010)	$	486,358
Interest		1,246
		487,604
Expenses:
Management fees		1,251,293
Distribution and service fees:
A Class		204
C Class		238
R Class		84
Directors’ fees and expenses		4,092
		1,255,911
Net investment income (loss)		(768,307	)
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on investment transactions		16,099,660
Change in net unrealized appreciation (depreciation) on investments		25,380,268
Net realized and unrealized gain (loss)		41,479,928
Net Increase (Decrease) in Net Assets Resulting from Operations	$	40,711,621

See Notes to Financial Statements.

14

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	(768,307	)	$	(794,456	)
Net realized gain (loss)		16,099,660			28,645,395
Change in net unrealized appreciation (depreciation)		25,380,268			12,832,897
Net increase (decrease) in net assets resulting from operations		40,711,621			40,683,836
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		1,963,813			(13,020,566	)
Redemption Fees
Increase in net assets from redemption fees		10,078			15,637
Net increase (decrease) in net assets		42,685,512			27,678,907
Net Assets
Beginning of period		146,965,768			119,286,861
End of period	$	189,651,280		$	146,965,768
Accumulated net investment loss	$	(768,307	)		—

See Notes to Financial Statements.

15

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. New Opportunities Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing primarily in common stocks of small- and mid-sized companies that management believes will increase in value over time.

The fund is authorized to issue the Investor Class, the Institutional Class, the A Class, the C Class and the R Class. The A Class may incur an initial sales charge. The A Class and C Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee. Sale of the Institutional Class, A Class, C Class and R Class commenced on March 1, 2010.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost.

16

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Redemption — The fund may impose a 2.00% redemption fee on shares held less than 180 days. The fee may not be applicable to all classes. The redemption fee is retained by the fund and helps cover transaction costs that long-term investors may bear when the fund sells securities to meet investor redemptions.

17

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The annual management fee schedule ranges from 1.10% to 1.50% for the Investor Class, A Class, C Class and R Class. The Institutional Class is 0.20% less at each point within the range. The effective annual management fee for each class for the six months ended April 30, 2011 was 1.50% for the Investor Class, A Class, C Class and R Class and 1.30% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a separate Master Distribution and Individual Shareholder Services Plan for each of the A Class, C Class and R Class (collectively the plans), pursuant to Rule 12b-1 of the 1940 Act. The plans provide that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The plans provide that the C Class will pay ACIS an annual distribution and service fee of 1.00%, of which 0.25% is paid for individual shareholder services and 0.75% is paid for distribution services. The plans provide that the R Class will pay ACIS an annual distribution and service fee of 0.50%. The fees are computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services. Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMorgan Chase Bank (JPMCB) is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $79,523,706 and $80,926,971, respectively.

18

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010(1)
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		200,000,000						200,000,000
Sold		1,513,841		$	12,052,301			1,028,023		$	6,286,589
Redeemed		(1,310,778	)		(10,173,528	)		(3,220,394	)		(19,503,133	)
		203,063			1,878,773			(2,192,371	)		(13,216,544	)
Institutional Class/Shares Authorized		25,000,000						25,000,000
Sold		—			—			4,119			25,000
A Class/Shares Authorized		25,000,000						25,000,000
Sold		9,472			76,145			19,550			120,712
Redeemed		—			—			(1,826	)		(11,798	)
		9,472			76,145			17,724			108,914
C Class/Shares Authorized		25,000,000						25,000,000
Sold		1,012			8,441			5,845			36,000
R Class/Shares Authorized		25,000,000						25,000,000
Sold		57			454			4,287			26,064
Net increase (decrease)		213,604		$	1,963,813			(2,160,396	)	$	(13,020,566	)

(1) March 1, 2010 (commencement of sale) through October 31, 2010 for the Institutional Class, A Class, C Class and R Class.

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• •Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• •Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2		Level 3
Investment Securities
Common Stocks	$	183,127,087		—		—
Temporary Cash Investments		79,734	$	5,600,000		—
Total Value of Investment Securities	$	183,206,821	$	5,600,000		—

19

7. Risk Factors

The fund invests in common stocks of small companies. Because of this, it may be subject to greater risk and market fluctuations than a fund investing in larger, more established companies.

The fund’s investment process may result in high portfolio turnover, which could mean high transaction costs, affecting both performance and capital gains tax liabilities to investors.

8. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	140,141,596
Gross tax appreciation of investments	$	50,266,932
Gross tax depreciation of investments		(1,601,707	)
Net tax appreciation (depreciation) of investments	$	48,665,225

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(66,626,564), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers of $(33,198,598) and $(33,427,966) expire in 2016 and 2017, respectively.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

20

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	6.86		$	5.06		$	5.12		$	8.58		$	6.44		$	5.63
Income From Investment Operations
Net Investment    Income (Loss)		(0.04	)(2)		(0.04	)(2)		(0.02	)(2)		(0.05	)(2)		(0.07	)		(0.06	)
Net Realized and    Unrealized Gain (Loss)		1.95			1.84			(0.04	)		(3.41	)		2.21			0.87
Total From    Investment Operations		1.91			1.80			(0.06	)		(3.46	)		2.14			0.81
Net Asset Value, End of Period	$	8.77		$	6.86		$	5.06		$	5.12		$	8.58		$	6.44
Total Return(3)		27.84	%		33.57	%		(1.17	)%		(40.33	)%		33.23	%		14.39	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.50	%(4)		1.51	%		1.50	%		1.50	%		1.50	%		1.50	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.92	)%(4)		(0.59	)%		(0.51	)%		(0.66	)%		(0.83	)%		(0.84	)%
Portfolio Turnover Rate		48	%		181	%		206	%		159	%		201	%		298	%
Net Assets, End of Period (in thousands)	$	189,280		$	146,747		$	119,287		$	146,932		$	270,428		$	247,876

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

21

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	6.87		$	6.07
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.03	)		(0.01	)
Net Realized and Unrealized Gain (Loss)		1.94			0.81
Total From Investment Operations		1.91			0.80
Net Asset Value, End of Period	$	8.78		$	6.87
Total Return(4)		27.80	%		13.18	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.30	%(5)		1.31	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.72	)%(5)		(0.29	)%(5)
Portfolio Turnover Rate		48	%		181	%(6)
Net Assets, End of Period (in thousands)	$	36		$	28

(1) Six months ended April 30, 2011 (unaudited).

(2) March 1, 2010 (commencement of sale) through October 31, 2010.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2010.

See Notes to Financial Statements.

22

A Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	6.85		$	6.07
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.05	)		(0.03	)
Net Realized and Unrealized Gain (Loss)		1.94			0.81
Total From Investment Operations		1.89			0.78
Net Asset Value, End of Period	$	8.74		$	6.85
Total Return(4)		27.59	%		12.85	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.75	%(5)		1.76	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(1.17	)%(5)		(0.67	)%(5)
Portfolio Turnover Rate		48	%		181	%(6)
Net Assets, End of Period (in thousands)	$	238		$	121

(1) Six months ended April 30, 2011 (unaudited).

(2) March 1, 2010 (commencement of sale) through October 31, 2010.

(3) Computed using average shares outstanding throughout the period

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2010.

See Notes to Financial Statements.

23

C Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	6.81		$	6.07
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.07	)		(0.06	)
Net Realized and Unrealized Gain (Loss)		1.92			0.80
Total From Investment Operations		1.85			0.74
Net Asset Value, End of Period	$	8.66		$	6.81
Total Return(4)		27.17	%		12.19	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.50	%(5)		2.51	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(1.92	)%(5)		(1.46	)%(5)
Portfolio Turnover Rate		48	%		181	%(6)
Net Assets, End of Period (in thousands)	$	59		$	40

(1) Six months ended April 30, 2011 (unaudited).

(2) March 1, 2010 (commencement of sale) through October 31, 2010.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2010.

See Notes to Financial Statements.

24

R Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	6.84		$	6.07
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.06	)		(0.04	)
Net Realized and Unrealized Gain (Loss)		1.93			0.81
Total From Investment Operations		1.87			0.77
Net Asset Value, End of Period	$	8.71		$	6.84
Total Return(4)		27.34	%		12.69	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.00	%(5)		2.01	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(1.42	)%(5)		(0.99	)%(5)
Portfolio Turnover Rate		48	%		181	%(6)
Net Assets, End of Period (in thousands)	$	38		$	29

(1) Six months ended April 30, 2011 (unaudited).

(2) March 1, 2010 (commencement of sale) through October 31, 2010.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2010.

See Notes to Financial Statements.

25

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

26

Notes

27

Notes

28

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71838   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

NT Growth Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	11
Statement of Operations	12
Statement of Changes in Net Assets	13
Notes to Financial Statements	14
Financial Highlights	19
Additional Information	20

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	Since Inception	Inception Date
Institutional Class	ACLTX	17.12%	19.83%	6.73%	5/12/06
Russell 1000 Growth Index	—	16.96%	20.87%	5.06%(2)	—

(1) Total returns for periods less than one year are not annualized.

(2) Since 4/30/06, the date nearest the Institutional Class’s inception for which data are available.

Total Annual Fund Operating Expenses

Institutional Class      0.79%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com.

Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Exxon Mobil Corp.	5.0%
Apple, Inc.	4.7%
Oracle Corp.	2.8%
Schlumberger Ltd.	2.5%
Coca-Cola Co. (The)	2.3%
QUALCOMM, Inc.	2.2%
Accenture plc, Class A	1.8%
United Parcel Service, Inc., Class B	1.7%
Express Scripts, Inc.	1.7%
Cisco Systems, Inc.	1.7%
Top Five Industries	% of net assets
Computers & Peripherals	8.2%
Oil, Gas & Consumable Fuels	7.9%
Software	6.7%
Machinery	5.1%
IT Services	5.0%
Types of Investments in Portfolio	% of net assets
Common Stocks	98.7%
Temporary Cash Investments	1.3%
Other Assets and Liabilities	—*
* Category is less than 0.05% of total net assets.

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Institutional Class	$1,000	$1,171.20	$4.20	0.78%
Hypothetical
Institutional Class	$1,000	$1,020.93	$3.91	0.78%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 98.7%
AEROSPACE & DEFENSE — 2.3%
Honeywell International, Inc.		100,890	$	6,177,495
Rockwell Collins, Inc.		20,489		1,292,856
Textron, Inc.		99,922		2,607,964
				10,078,315
AIR FREIGHT & LOGISTICS — 1.7%
United Parcel Service, Inc., Class B		100,979		7,570,396
AUTO COMPONENTS — 2.1%
Autoliv, Inc.		46,791		3,749,363
BorgWarner, Inc.(1)		69,536		5,370,960
				9,120,323
AUTOMOBILES — 0.6%
Harley-Davidson, Inc.		73,394		2,734,660
BEVERAGES — 3.2%
Coca-Cola Co. (The)		153,273		10,339,797
Hansen Natural Corp.(1)		20,034		1,325,249
PepsiCo, Inc.		38,143		2,627,671
				14,292,717
BIOTECHNOLOGY — 1.6%
Alexion Pharmaceuticals, Inc.(1)		5,610		543,553
Amgen, Inc.(1)		49,382		2,807,367
Gilead Sciences, Inc.(1)		67,502		2,621,777
Human Genome Sciences, Inc.(1)		34,891		1,028,238
				7,000,935
CAPITAL MARKETS — 2.1%
BlackRock, Inc.		20,902		4,095,538
Charles Schwab Corp. (The)		182,473		3,341,080
T. Rowe Price Group, Inc.		30,247		1,943,370
				9,379,988
CHEMICALS — 3.2%
E.I. du Pont de Nemours & Co.		89,647		5,091,053
LyondellBasell Industries NV, Class A(1)		52,117		2,319,206
PPG Industries, Inc.		50,078		4,740,884
Sigma-Aldrich Corp.		29,401		2,075,123
				14,226,266
COMMUNICATIONS EQUIPMENT — 4.8%
Cisco Systems, Inc.		416,591		7,315,338
Juniper Networks, Inc.(1)		79,768		3,057,508
QUALCOMM, Inc.		173,848		9,881,520
Riverbed Technology, Inc.(1)		31,873		1,120,017
				21,374,383
COMPUTERS & PERIPHERALS — 8.2%
Apple, Inc.(1)		59,724		20,797,688
Dell, Inc.(1)		249,196		3,865,030
EMC Corp.(1)		250,997		7,113,255
NetApp, Inc.(1)		85,052		4,421,003
				36,196,976
CONSUMER FINANCE — 1.2%
American Express Co.		108,070		5,304,076
DIVERSIFIED — 0.1%
iShares Russell 1000 Growth Index Fund		8,471		529,014
DIVERSIFIED TELECOMMUNICATION SERVICES — 0.5%
Verizon Communications, Inc.		55,173		2,084,436
ELECTRICAL EQUIPMENT — 1.9%
Emerson Electric Co.		45,327		2,754,069
Rockwell Automation, Inc.		62,101		5,410,860
				8,164,929
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 0.5%
Jabil Circuit, Inc.		120,978		2,400,204
ENERGY EQUIPMENT & SERVICES — 3.4%
Core Laboratories NV		15,073		1,446,706
Halliburton Co.		49,246		2,485,938
Schlumberger Ltd.		124,009		11,129,808
				15,062,452
FOOD & STAPLES RETAILING — 2.9%
Costco Wholesale Corp.		79,637		6,444,226
Walgreen Co.		108,519		4,635,932
Whole Foods Market, Inc.		27,756		1,741,966
				12,822,124
FOOD PRODUCTS — 2.3%
General Mills, Inc.		48,044		1,853,537
Hershey Co. (The)		53,622		3,094,526
Kellogg Co.		65,979		3,778,617
Mead Johnson Nutrition Co.		23,485		1,570,677
				10,297,357
HEALTH CARE EQUIPMENT & SUPPLIES — 4.0%
Cooper Cos., Inc. (The)		13,569		1,016,318
Covidien plc		75,622		4,211,389
DENTSPLY International, Inc.		21,393		803,093
Edwards Lifesciences Corp.(1)		18,069		1,560,258
Gen-Probe, Inc.(1)		16,092		1,334,349
Intuitive Surgical, Inc.(1)		4,806		1,680,658
Medtronic, Inc.		82,874		3,459,990

8

	Shares		Value
St. Jude Medical, Inc.	41,554	$	2,220,646
Zimmer Holdings, Inc.(1)	23,441		1,529,525
			17,816,226
HEALTH CARE PROVIDERS & SERVICES — 1.7%
Express Scripts, Inc.(1)	131,193		7,443,891
HOTELS, RESTAURANTS & LEISURE — 3.3%
Chipotle Mexican Grill, Inc.(1)	2,238		597,076
Las Vegas Sands Corp.(1)	34,300		1,612,443
McDonald’s Corp.	78,898		6,178,502
Starbucks Corp.	75,913		2,747,292
Starwood Hotels & Resorts Worldwide, Inc.	59,189		3,525,889
			14,661,202
HOUSEHOLD DURABLES — 0.4%
Whirlpool Corp.	18,911		1,629,750
HOUSEHOLD PRODUCTS — 1.0%
Church & Dwight Co., Inc.	15,564		1,283,719
Procter & Gamble Co. (The)	49,460		3,209,954
			4,493,673
INDUSTRIAL CONGLOMERATES — 1.3%
General Electric Co.	276,677		5,658,045
INSURANCE — 0.8%
Aflac, Inc.	66,192		3,719,329
INTERNET & CATALOG RETAIL — 0.4%
Netflix, Inc.(1)	7,719		1,795,980
INTERNET SOFTWARE & SERVICES — 1.5%
Google, Inc., Class A(1)	11,848		6,446,497
IT SERVICES — 5.0%
Accenture plc, Class A	135,838		7,760,425
Automatic Data Processing, Inc.	74,765		4,063,478
International Business Machines Corp.	40,911		6,978,598
MasterCard, Inc., Class A	11,888		3,279,780
			22,082,281
LIFE SCIENCES TOOLS & SERVICES — 0.5%
Bruker Corp.(1)	21,906		432,425
Thermo Fisher Scientific, Inc.(1)	28,375		1,702,216
			2,134,641
MACHINERY — 5.1%
Caterpillar, Inc.	35,324		4,076,743
Deere & Co.	49,901		4,865,348
Eaton Corp.	103,793		5,556,039
Illinois Tool Works, Inc.	91,847		5,364,783
Joy Global, Inc.	26,999		2,725,549
			22,588,462
MEDIA — 1.7%
Scripps Networks Interactive, Inc., Class A	56,797		2,920,502
Walt Disney Co. (The)	104,531		4,505,286
			7,425,788
METALS & MINING — 2.1%
Cliffs Natural Resources, Inc.	44,025		4,126,023
Freeport-McMoRan Copper & Gold, Inc.	67,966		3,740,169
Newmont Mining Corp.	27,550		1,614,706
			9,480,898
MULTILINE RETAIL — 1.5%
Kohl’s Corp.	40,317		2,125,109
Target Corp.	92,352		4,534,483
			6,659,592
OIL, GAS & CONSUMABLE FUELS — 7.9%
Cimarex Energy Co.	21,276		2,352,913
ConocoPhillips	48,406		3,820,685
Exxon Mobil Corp.	250,891		22,078,408
Occidental Petroleum Corp.	32,182		3,678,081
Southwestern Energy Co.(1)	68,777		3,016,559
			34,946,646
PERSONAL PRODUCTS — 0.4%
Estee Lauder Cos., Inc. (The), Class A	17,538		1,701,186
PHARMACEUTICALS — 2.7%
Abbott Laboratories	119,988		6,244,175
Allergan, Inc.	52,477		4,175,070
Novo Nordisk A/S B Shares	13,618		1,721,487
			12,140,732
REAL ESTATE MANAGEMENT & DEVELOPMENT — 0.6%
CB Richard Ellis Group, Inc., Class A(1)	90,907		2,428,126
ROAD & RAIL — 0.6%
Union Pacific Corp.	25,558		2,644,486
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 2.8%
Altera Corp.	62,561		3,046,721
Broadcom Corp., Class A(1)	17,913		630,179
Linear Technology Corp.	84,628		2,945,054
RF Micro Devices, Inc.(1)	87,857		585,128
Texas Instruments, Inc.	111,784		3,971,685
Xilinx, Inc.	29,045		1,012,509
			12,191,276

9

Shares Value

SOFTWARE — 6.7%
Citrix Systems, Inc.(1)	25,329	$	2,136,248
CommVault Systems, Inc.(1)	12,543		494,069
Intuit, Inc.(1)	40,500		2,250,180
Microsoft Corp.	192,731		5,014,861
Oracle Corp.	345,769		12,464,972
Red Hat, Inc.(1)	59,522		2,825,509
salesforce.com, inc.(1)	9,792		1,357,171
VMware, Inc., Class A(1)	32,249		3,077,522
			29,620,532
SPECIALTY RETAIL — 3.1%
American Eagle Outfitters, Inc.	87,176		1,356,459
Home Depot, Inc. (The)	180,875		6,717,697
Limited Brands, Inc.	98,049		4,035,697
OfficeMax, Inc.(1)	48,546		483,518
Williams-Sonoma, Inc.	28,739		1,247,560
			13,840,931
WIRELESS TELECOMMUNICATION SERVICES — 1.0%
Crown Castle International Corp.(1)	103,662		4,442,953
TOTAL COMMON STOCKS (Cost $328,043,392)			436,632,674

	Principal Amount/Shares		Value
Temporary Cash Investments — 1.3%
FHLB Discount Notes, 0.001%, 5/2/11(2)	$	5,800,000	$	5,800,000
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares		52,612		52,612
TOTAL TEMPORARY CASH INVESTMENTS (Cost $5,852,612)				5,852,612
TOTAL INVESTMENT SECURITIES — 100.0% (Cost $333,896,004)				442,485,286
OTHER ASSETS AND LIABILITIES(3)				(8,147	)
TOTAL NET ASSETS — 100.0%			$	442,477,139

Forward Foreign Currency Exchange Contracts
Contracts to Sell		Counterparty	Settlement Date	Value	Unrealized Gain (Loss)
5,616,404	DKK for USD	UBS AG	5/31/11	$1,114,768	$(14,834)

(Value on Settlement Date $1,099,934)

Notes to Schedule of Investments

DKK = Danish Krone

FHLB = Federal Home Loan Bank

USD = United States Dollar

(1) Non-income producing.

(2) The rate indicated is the yield to maturity at purchase.

(3) Category is less than 0.05% of total net assets.

See Notes to Financial Statements.

10

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $333,896,004)	$	442,485,286
Receivable for investments sold		6,783,022
Receivable for capital shares sold		637,976
Dividends and interest receivable		331,411
		450,237,695
Liabilities
Payable for investments purchased		7,472,883
Unrealized loss on forward foreign currency exchange contracts		14,834
Accrued management fees		272,839
		7,760,556
Net Assets	$	442,477,139
Institutional Class Capital Shares, $0.01 Par Value
Shares authorized		150,000,000
Shares outstanding		34,374,323
Net Asset Value Per Share	$	12.87
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	330,352,723
Undistributed net investment income		750,616
Undistributed net realized gain		2,797,950
Net unrealized appreciation		108,575,850
	$	442,477,139

See Notes to Financial Statements.

11

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $4,804)	$	3,156,516
Interest		2,128
		3,158,644
Expenses:
Management fees		1,489,770
Directors’ fees and expenses		9,350
		1,499,120
Net investment income (loss)		1,659,524
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		15,209,205
Futures contract transactions		191,522
Foreign currency transactions		(68,065	)
		15,332,662
Change in net unrealized appreciation (depreciation) on:
Investments		43,282,642
Translation of assets and liabilities in foreign currencies		(14,421	)
		43,268,221
Net realized and unrealized gain (loss)		58,600,883
Net Increase (Decrease) in Net Assets Resulting from Operations	$	60,260,407

See Notes to Financial Statements.

12

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	1,659,524		$	1,690,758
Net realized gain (loss)		15,332,662			11,144,590
Change in net unrealized appreciation (depreciation)		43,268,221			35,098,212
Net increase (decrease) in net assets resulting from operations		60,260,407			47,933,560
Distributions to Shareholders
From net investment income		(2,311,137	)		(996,841	)
Capital Share Transactions
Proceeds from shares sold		54,359,046			100,015,427
Proceeds from reinvestment of distributions		2,311,137			—
Payments for shares redeemed		(12,559,240	)		(14,872,070	)
Net increase (decrease) in net assets from capital share transactions		44,110,943			85,143,357
Net increase (decrease) in net assets		102,060,213			132,080,076
Net Assets
Beginning of period		340,416,926			208,336,850
End of period	$	442,477,139		$	340,416,926
Undistributed net investment income	$	750,616		$	1,402,229
Transactions in Shares of the Fund
Sold		4,473,125			9,964,567
Issued in reinvestment of distributions		196,358			—
Redeemed		(1,083,251	)		(1,474,183	)
Net increase (decrease) in shares of the fund		3,586,232			8,490,384

See Notes to Financial Statements.

13

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. NT Growth Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing primarily in equity securities of larger-sized companies that management believes will increase in value over time. The fund is not permitted to invest in any securities issued by companies assigned the Global Industry Classification Standard for the tobacco industry.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Exchange-traded futures contracts are valued at the settlement price as provided by the appropriate clearing corporation. Forward foreign currency exchange contracts are valued at the mean of the latest bid and asked prices of the forward currency rates as provided by an independent pricing service.

The value of investments initially expressed in foreign currencies is translated into U.S. dollars at prevailing exchange rates.

14

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Foreign Currency Translations — All assets and liabilities initially expressed in foreign currencies are translated into U.S. dollars at prevailing exchange rates at period end. The fund may enter into spot foreign currency exchange contracts to facilitate transactions denominated in a foreign currency. Purchases and sales of investment securities, dividend and interest income, spot foreign currency exchange contracts, and expenses are translated at the rates of exchange prevailing on the respective dates of such transactions. Net realized and unrealized foreign currency exchange gains or losses related to investment securities are a component of net realized gain (loss) on investment transactions and change in net unrealized appreciation (depreciation) on investments, respectively.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

15

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee). The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on the daily net assets of the fund and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The strategy assets of the fund include the assets of Growth Fund, one fund in a series issued by the corporation. The annual management fee schedule ranges from 0.600% to 0.800%. The effective annual management fee for the six months ended April 30, 2011 was 0.78%.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, American Century Investment Services, Inc., and the corporation’s transfer agent, American Century Services, LLC. The fund is wholly owned, in aggregate, by various funds in a series issued by American Century Asset Allocation Portfolios, Inc. (ACAAP). ACAAP does not invest in the fund for the purpose of exercising management or control.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a securities lending agreement with JPMorgan Chase Bank (JPMCB) and a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMCB is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $176,477,589 and $136,137,619, respectively.

5. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

16

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2			Level 3
Investment Securities
Common Stocks	$	434,911,187	$	1,721,487			—
Temporary Cash Investments		52,612		5,800,000			—
Total Value of Investment Securities	$	434,963,799	$	7,521,487			—
Other Financial Instruments
Total Unrealized Gain (Loss) on Forward Foreign Currency Exchange Contracts		—	$	(14,834	)		—

6. Derivative Instruments

Equity Price Risk — The fund is subject to equity price risk in the normal course of pursuing its investment objectives. A fund may enter into futures contracts based on an equity index in order to manage its exposure to changes in market conditions. A fund may purchase futures contracts to gain exposure to increases in market value or sell futures contracts to protect against a decline in market value. Upon entering into a futures contract, a fund is required to deposit either cash or securities in an amount equal to a certain percentage of the contract value (initial margin). Subsequent payments (variation margin) are made or received daily, in cash, by a fund. The variation margin is equal to the daily change in the contract value and is recorded as unrealized gains and losses. A fund recognizes a realized gain or loss when the contract is closed or expires. Net realized and unrealized gains or losses occurring during the holding period of futures contracts are a component of net realized gain (loss) on futures contract transactions and change in net unrealized appreciation (depreciation) on futures contracts, respectively. One of the risks of entering into futures contracts is the possibility that the change in value of the contract may not correlate with the changes in value of the underlying securities. During the period, the fund infrequently purchased equity price risk derivative instruments for temporary investment purposes.

Foreign Currency Risk — The fund is subject to foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The value of foreign investments held by a fund may be significantly affected by changes in foreign currency exchange rates. The dollar value of a foreign security generally decreases when the value of the dollar rises against the foreign currency in which the security is denominated and tends to increase when the value of the dollar declines against such foreign currency. A fund may enter into forward foreign currency exchange contracts to reduce a fund’s exposure to foreign currency exchange rate fluctuations. The net U.S. dollar value of foreign currency underlying all contractual commitments held by a fund and the resulting unrealized appreciation or depreciation are determined daily. Realized gain or loss is recorded upon the termination of the contract. Net realized and unrealized gains or losses occurring during the holding period of forward foreign currency exchange contracts are a component of net realized gain (loss) on foreign currency transactions and change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies, respectively. A fund bears the risk of an unfavorable change in the foreign currency exchange rate underlying the forward contract. Additionally, losses, up to the fair value, may arise if the counterparties do not perform under the contract terms. The risk of loss from non-performance by the counterparty may be reduced by the use of master netting agreements. The foreign currency risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

17

Value of Derivative Instruments as of April 30, 2011
	Asset Derivatives				Liability Derivatives
Type of Risk Exposure	Location on Statement of Assets and Liabilities	Value			Location on Statement of Assets and Liabilities	Value
Foreign Currency Risk	Unrealized gain on forward foreign currency exchange contracts		—		Unrealized loss on forward foreign currency exchange contracts	$	14,834
Effect of Derivative Instruments on the Statement of Operations for the Six Months Ended April 30, 2011
	Net Realized Gain (Loss)				Change in Net Unrealized Appreciation (Depreciation)
Type of Risk Exposure	Location on Statement of Operations	Value			Location on Statement of Operations	Value
Equity Price Risk	Net realized gain (loss) on futures contract transactions	$	191,522		Change in net unrealized appreciation (depreciation) on futures contracts		—
Foreign Currency Risk	Net realized gain (loss) on foreign currency transactions		(72,216	)	Change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies	$	(11,957	)
		$	119,306			$	(11,957	)

7. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	338,885,052
Gross tax appreciation of investments	$	104,571,730
Gross tax depreciation of investments		(971,496	)
Net tax appreciation (depreciation) of investments	$	103,600,234

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(7,239,737), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers expire in 2017.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

18

Financial Highlights

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	11.06		$	9.34		$	8.13		$	12.87		$	10.57		$	10.00
Income From Investment Operations
Net Investment    Income (Loss)		0.05	(3)		0.06	(3)		0.06	(3)		0.04	(3)		0.04			0.01
Net Realized and    Unrealized Gain (Loss)		1.84			1.71			1.21			(4.19	)		2.29			0.56
Total From    Investment Operations		1.89			1.77			1.27			(4.15	)		2.33			0.57
Distributions
From Net    Investment Income		(0.08	)		(0.05	)		(0.06	)		(0.03	)		(0.03	)		—
From Net Realized Gains		—			—			—			(0.56	)		—			—
Total Distributions		(0.08	)		(0.05	)		(0.06	)		(0.59	)		(0.03	)		—
Net Asset Value, End of Period	$	12.87		$	11.06		$	9.34		$	8.13		$	12.87		$	10.57
Total Return(4)		17.12	%		18.94	%		15.88	%		(33.68	)%		22.12	%		5.70	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.78	%(5)		0.79	%		0.80	%		0.80	%		0.80	%		0.80	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		0.86	%(5)		0.63	%		0.67	%		0.38	%		0.35	%		0.36	%(5)
Portfolio Turnover Rate		36	%		95	%		132	%		136	%		140	%		57	%
Net Assets, End of Period (in thousands)	$	442,477		$	340,417		$	208,337		$	83,440		$	88,446		$	58,983

(1) Six months ended April 30, 2011 (unaudited).

(2) May 12, 2006 (fund inception) through October 31, 2006.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

19

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

20

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71844   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

NT VistaSM Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	11
Statement of Operations	12
Statement of Changes in Net Assets	13
Notes to Financial Statements	14
Financial Highlights	20
Additional Information	21

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12–18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	Since Inception	Inception Date
Institutional Class	ACLWX	20.34%	25.11%	2.65%	5/12/06
Russell Midcap Growth Index	—	22.62%	27.40%	5.59%(2)	—

(1) Total returns for periods less than one year are not annualized.

(2) Since 4/30/06, the date nearest the Institutional Class’s inception for which data are available.

Total Annual Fund Operating Expenses

Institutional Class      0.80%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. International investing involves special risks, such as political instability and currency fluctuations. Historically, small company stocks have been more volatile than the stocks of larger, more established companies.

Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Whole Foods Market, Inc.	2.5%
Netflix, Inc.	2.4%
SXC Health Solutions Corp.	2.1%
priceline.com, Inc.	2.1%
BE Aerospace, Inc.	2.1%
National Oilwell Varco, Inc.	1.7%
Albemarle Corp.	1.5%
Cognizant Technology Solutions Corp., Class A	1.5%
TransDigm Group, Inc.	1.5%
Concho Resources, Inc.	1.5%
Top Five Industries	% of net assets
Machinery	7.7%
Semiconductors & Semiconductor Equipment	6.0%
Software	4.9%
Energy Equipment & Services	4.7%
Internet & Catalog Retail	4.5%
Types of Investments in Portfolio	% of net assets
Domestic Common Stocks	88.0%
Foreign Common Stocks*	10.4%
Total Common Stocks	98.4%
Temporary Cash Investments	1.1%
Other Assets and Liabilities	0.5%
*Includes depositary shares, dual listed securities and foreign ordinary shares.

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Institutional Class	$1,000	$1,203.40	$4.37	0.80%
Hypothetical
Institutional Class	$1,000	$1,020.83	$4.01	0.80%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 98.4%
AEROSPACE & DEFENSE — 3.6%
BE Aerospace, Inc.(1)		109,800	$	4,237,182
TransDigm Group, Inc.(1)		36,300		3,023,790
				7,260,972
AIR FREIGHT & LOGISTICS — 0.5%
C.H. Robinson Worldwide, Inc.		13,200		1,058,376
AIRLINES — 0.5%
Alaska Air Group, Inc.(1)		16,000		1,053,920
AUTO COMPONENTS — 1.3%
BorgWarner, Inc.(1)		35,200		2,718,848
AUTOMOBILES — 0.4%
Harley-Davidson, Inc.		24,200		901,692
BIOTECHNOLOGY — 2.7%
Alexion Pharmaceuticals, Inc.(1)		28,900		2,800,121
United Therapeutics Corp.(1)		15,100		1,011,096
Vertex Pharmaceuticals, Inc.(1)		30,900		1,700,118
				5,511,335
CAPITAL MARKETS ��� 3.2%
Affiliated Managers Group, Inc.(1)		11,600		1,265,328
American Capital Ltd.(1)		89,100		915,057
KKR & Co. LP		63,263		1,199,466
Lazard Ltd., Class A		47,300		1,939,300
Raymond James Financial, Inc.		34,100		1,278,750
				6,597,901
CHEMICALS — 2.9%
Albemarle Corp.		44,100		3,111,255
CF Industries Holdings, Inc.		12,400		1,755,220
International Flavors & Fragrances, Inc.		17,700		1,124,304
				5,990,779
COMMERCIAL SERVICES & SUPPLIES — 1.1%
Stericycle, Inc.(1)		25,000		2,282,000
COMMUNICATIONS EQUIPMENT — 1.2%
Aruba Networks, Inc.(1)		33,600		1,207,248
F5 Networks, Inc.(1)		11,600		1,175,776
				2,383,024
CONSTRUCTION & ENGINEERING — 1.1%
Foster Wheeler AG(1)		29,500		1,049,315
KBR, Inc.		30,800		1,181,796
				2,231,111
CONSUMER FINANCE — 1.1%
Discover Financial Services		90,600		2,250,504
CONTAINERS & PACKAGING — 1.1%
Crown Holdings, Inc.(1)		60,300		2,255,220
ELECTRICAL EQUIPMENT — 2.8%
Cooper Industries plc		32,500		2,143,375
Polypore International, Inc.(1)		17,882		1,104,571
Rockwell Automation, Inc.		28,200		2,457,066
				5,705,012
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 1.5%
Jabil Circuit, Inc.		59,200		1,174,528
Trimble Navigation Ltd.(1)		38,900		1,822,076
				2,996,604
ENERGY EQUIPMENT & SERVICES — 4.7%
Atwood Oceanics, Inc.(1)		24,800		1,114,264
Core Laboratories NV		10,700		1,026,986
Dril-Quip, Inc.(1)		13,200		1,010,592
FMC Technologies, Inc.(1)		31,550		1,466,444
McDermott International, Inc.(1)		64,600		1,491,614
National Oilwell Varco, Inc.		45,000		3,451,050
				9,560,950
FOOD & STAPLES RETAILING — 2.5%
Whole Foods Market, Inc.		80,800		5,071,008
FOOD PRODUCTS — 1.3%
J.M. Smucker Co. (The)		13,800		1,035,966
Mead Johnson Nutrition Co.		25,200		1,685,376
				2,721,342
HEALTH CARE EQUIPMENT & SUPPLIES — 3.7%
C.R. Bard, Inc.		23,500		2,508,625
Hologic, Inc.(1)		45,300		997,506
Mettler-Toledo International, Inc.(1)		11,700		2,192,580
Varian Medical Systems, Inc.(1)		25,000		1,755,000
				7,453,711
HEALTH CARE PROVIDERS & SERVICES — 0.8%
Express Scripts, Inc.(1)		28,100		1,594,394
HEALTH CARE TECHNOLOGY — 2.1%
SXC Health Solutions Corp.(1)		77,900		4,296,964
HOTELS, RESTAURANTS & LEISURE — 3.8%
Chipotle Mexican Grill, Inc.(1)		8,100		2,160,999
Panera Bread Co., Class A(1)		15,500		1,877,205
Royal Caribbean Cruises Ltd.(1)		42,600		1,696,332
Starwood Hotels & Resorts Worldwide, Inc.		33,000		1,965,810
				7,700,346

8

Shares Value

HOUSEHOLD PRODUCTS — 1.0%
Church & Dwight Co., Inc.	25,600	$	2,111,488
INTERNET & CATALOG RETAIL — 4.5%
Netflix, Inc.(1)	20,700		4,816,269
priceline.com, Inc.(1)	7,800		4,266,678
			9,082,947
INTERNET SOFTWARE & SERVICES — 3.2%
Baidu, Inc. ADR(1)	13,100		1,945,612
MercadoLibre, Inc.	10,934		999,368
VeriSign, Inc.	71,000		2,624,160
WebMD Health Corp.(1)	16,100		931,707
			6,500,847
IT SERVICES — 2.7%
Alliance Data Systems Corp.(1)	11,000		1,045,000
Cognizant Technology Solutions Corp., Class A(1)	36,800		3,050,720
VeriFone Systems, Inc.(1)	25,800		1,414,356
			5,510,076
LEISURE EQUIPMENT & PRODUCTS — 0.4%
Brunswick Corp.	33,700		787,569
LIFE SCIENCES TOOLS & SERVICES — 2.1%
Illumina, Inc.(1)	32,800		2,328,144
Waters Corp.(1)	20,600		2,018,800
			4,346,944
MACHINERY — 7.7%
AGCO Corp.(1)	47,200		2,717,776
Cummins, Inc.	20,500		2,463,690
Harsco Corp.	27,400		975,440
Joy Global, Inc.	23,500		2,372,325
Manitowoc Co., Inc. (The)	20,862		462,928
Terex Corp.(1)	27,811		967,267
Timken Co.	20,694		1,166,935
Titan International, Inc.	48,163		1,487,755
Trinity Industries, Inc.	28,800		1,042,560
WABCO Holdings, Inc.(1)	27,943		2,063,590
			15,720,266
MEDIA — 2.0%
CBS Corp., Class B	81,300		2,050,386
Imax Corp.(1)	59,077		2,072,421
			4,122,807
METALS & MINING — 2.1%
Cliffs Natural Resources, Inc.	27,200		2,549,184
Walter Energy, Inc.	12,600		1,741,572
			4,290,756
MULTILINE RETAIL — 1.0%
Dollar Tree, Inc.(1)	33,650		1,934,875
OIL, GAS & CONSUMABLE FUELS — 3.6%
Brigham Exploration Co.(1)	53,200		1,783,796
Concho Resources, Inc.(1)	28,000		2,991,800
SandRidge Energy, Inc.(1)	114,200		1,411,512
Whiting Petroleum Corp.(1)	17,600		1,223,200
			7,410,308
PHARMACEUTICALS — 0.6%
Shire plc	39,000		1,207,779
PROFESSIONAL SERVICES — 0.5%
Manpower, Inc.	14,800		980,500
REAL ESTATE MANAGEMENT & DEVELOPMENT — 2.2%
CB Richard Ellis Group, Inc., Class A(1)	90,500		2,417,255
Jones Lang LaSalle, Inc.	20,600		2,109,028
			4,526,283
ROAD & RAIL — 0.8%
Kansas City Southern(1)	28,100		1,632,891
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 6.0%
Altera Corp.	31,800		1,548,660
ARM Holdings plc	261,400		2,727,956
Atmel Corp.(1)	74,900		1,145,970
Cavium Networks, Inc.(1)	44,100		2,082,402
Cypress Semiconductor Corp.(1)	47,200		1,027,072
NXP Semiconductor NV(1)	27,700		925,180
Skyworks Solutions, Inc.(1)	56,400		1,774,344
Veeco Instruments, Inc.(1)	20,302		1,038,041
			12,269,625
SOFTWARE — 4.9%
Ariba, Inc.(1)	32,100		1,116,117
Autodesk, Inc.(1)	23,400		1,052,532
Check Point Software Technologies Ltd.(1)	23,100		1,268,883
Citrix Systems, Inc.(1)	32,200		2,715,748
Intuit, Inc.(1)	17,500		972,300
salesforce.com, inc.(1)	21,100		2,924,460
			10,050,040
SPECIALTY RETAIL — 3.7%
O’Reilly Automotive, Inc.(1)	35,400		2,090,724
PetSmart, Inc.	63,310		2,669,783
Williams-Sonoma, Inc.	62,500		2,713,125
			7,473,632
TEXTILES, APPAREL & LUXURY GOODS — 1.9%
Fossil, Inc.(1)	22,400		2,145,472
Lululemon Athletica, Inc.(1)	16,800		1,680,504
			3,825,976

9

Shares Value

TRADING COMPANIES & DISTRIBUTORS — 1.7%
Fastenal Co.	31,100	$	2,086,499
WESCO International, Inc.(1)	23,000		1,424,850
			3,511,349
WIRELESS TELECOMMUNICATION SERVICES — 1.9%
NII Holdings, Inc.(1)	24,900		1,035,342
SBA Communications Corp., Class A(1)	71,102		2,746,670
			3,782,012
TOTAL COMMON STOCKS (Cost $147,478,148)			200,674,983
Temporary Cash Investments — 1.1%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	45,451		45,451
Repurchase Agreement, Bank of America Securities, LLC, (collateralized by various U.S. Treasury obligations, 4.375%, 11/15/39, valued at $2,236,815), in a joint trading account at 0.02%, dated 4/29/11, due 5/2/11 (Delivery value $2,200,004)			2,200,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $2,245,451)			2,245,451
TOTAL INVESTMENT SECURITIES — 99.5% (Cost $149,723,599)			202,920,434
OTHER ASSETS AND LIABILITIES — 0.5%			946,104
TOTAL NET ASSETS — 100.0%		$	203,866,538

Forward Foreign Currency Exchange Contracts
Contracts to Sell		Counterparty	Settlement Date	Value	Unrealized Gain (Loss)
1,509,126	GBP for USD	Bank of America	5/31/11	$2,519,923	$(34,846)

(Value on Settlement Date $2,485,077)

Geographic Diversification
(as a % of net assets)
United States	88.0%
Canada	3.9%
United Kingdom	1.3%
Netherlands	1.0%
People’s Republic of China	1.0%
Bermuda	1.0%
Israel	0.6%
Ireland	0.6%
Switzerland	0.5%
Argentina	0.5%
Cash and Equivalents*	1.6%
*Includes temporary cash investments and other assets and liabilities.

Notes to Schedule of Investments

ADR = American Depositary Receipt

GBP = British Pound

USD = United States Dollar

(1) Non-income producing.

See Notes to Financial Statements.

10

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $149,723,599)	$	202,920,434
Receivable for investments sold		4,565,528
Receivable for capital shares sold		219,520
Dividends and interest receivable		52,675
		207,758,157
Liabilities
Payable for investments purchased		3,726,480
Unrealized loss on forward foreign currency exchange contracts		34,846
Accrued management fees		130,293
		3,891,619
Net Assets	$	203,866,538
Institutional Class Capital Shares, $0.01 Par Value
Shares authorized		150,000,000
Shares outstanding		17,950,409
Net Asset Value Per Share	$	11.36
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	146,982,350
Accumulated net investment loss		(190,261	)
Undistributed net realized gain		3,910,082
Net unrealized appreciation		53,164,367
	$	203,866,538

See Notes to Financial Statements.

11

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $953)	$	495,388
Interest		1,688
		497,076
Expenses:
Management fees		708,915
Directors’ fees and expenses		4,327
		713,242
Net investment income (loss)		(216,166	)
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		12,679,637
Futures contract transactions		293,119
Foreign currency transactions		(113,253	)
		12,859,503
Change in net unrealized appreciation (depreciation) on:
Investments		20,104,891
Translation of assets and liabilities in foreign currencies		(6,040	)
		20,098,851
Net realized and unrealized gain (loss)		32,958,354
Net Increase (Decrease) in Net Assets Resulting from Operations	$	32,742,188

See Notes to Financial Statements.

12

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	(216,166	)	$	(322,140	)
Net realized gain (loss)		12,859,503			8,492,963
Change in net unrealized appreciation (depreciation)		20,098,851			21,735,147
Net increase (decrease) in net assets resulting from operations		32,742,188			29,905,970
Distributions to Shareholders
From net investment income		—			(11,506	)
Capital Share Transactions
Proceeds from shares sold		25,703,327			46,264,949
Payments for shares redeemed		(15,882,562	)		(6,092,543	)
Net increase (decrease) in net assets from capital share transactions		9,820,765			40,172,406
Net increase (decrease) in net assets		42,562,953			70,066,870
Net Assets
Beginning of period		161,303,585			91,236,715
End of period	$	203,866,538		$	161,303,585
Accumulated undistributed net investment income (loss)	$	(190,261	)	$	25,905
Transactions in Shares of the Fund
Sold		2,442,695			5,628,784
Redeemed		(1,574,092	)		(719,862	)
Net increase (decrease) in shares of the fund		868,603			4,908,922

See Notes to Financial Statements.

13

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. NT Vista Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing primarily in equity securities of companies that are medium-sized and smaller at the time of purchase that management believes will increase in value. The fund is not permitted to invest in any securities issued by companies assigned the Global Industry Classification Standard for the tobacco industry.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Exchange-traded futures contracts are valued at the settlement price as provided by the appropriate clearing corporation. Forward foreign currency exchange contracts are valued at the mean of the latest bid and asked prices of the forward currency rates as provided by an independent pricing service.

The value of investments initially expressed in foreign currencies is translated into U.S. dollars at prevailing exchange rates.

14

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Foreign Currency Translations — All assets and liabilities initially expressed in foreign currencies are translated into U.S. dollars at prevailing exchange rates at period end. The fund may enter into spot foreign currency exchange contracts to facilitate transactions denominated in a foreign currency. Purchases and sales of investment securities, dividend and interest income, spot foreign currency exchange contracts, and expenses are translated at the rates of exchange prevailing on the respective dates of such transactions. Net realized and unrealized foreign currency exchange gains or losses related to investment securities are a component of net realized gain (loss) on investment transactions and change in net unrealized appreciation (depreciation) on investments, respectively.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. Additionally, non-U.S. tax returns filed by the fund due to investments in certain foreign securities remain subject to examination by the relevant taxing authority for seven years from the date of filing. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

15

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee). The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on the daily net assets of the fund and paid monthly in arrears. The annual management fee is 0.80%.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, American Century Investment Services, Inc., and the corporation’s transfer agent, American Century Services, LLC. The fund is wholly owned, in aggregate, by various funds in a series issued by American Century Asset Allocation Portfolios, Inc. (ACAAP). ACAAP does not invest in the fund for the purpose of exercising management or control.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMorgan Chase Bank (JPMCB) is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $104,580,114 and $95,920,467, respectively.

5. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

16

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2			Level 3
Investment Securities
Domestic Common Stocks	$	179,534,715		—			—
Foreign Common Stocks		17,204,533	$	3,935,735			—
Temporary Cash Investments		45,451		2,200,000			—
Total Value of Investment Securities	$	196,784,699	$	6,135,735			—
Other Financial Instruments
Total Unrealized Gain (Loss) on Forward Foreign Currency Exchange Contracts		—	$	(34,846	)		—

6. Derivative Instruments

Equity Price Risk — The fund is subject to equity price risk in the normal course of pursuing its investment objectives. A fund may enter into futures contracts based on an equity index in order to manage its exposure to changes in market conditions. A fund may purchase futures contracts to gain exposure to increases in market value or sell futures contracts to protect against a decline in market value. Upon entering into a futures contract, a fund is required to deposit either cash or securities in an amount equal to a certain percentage of the contract value (initial margin). Subsequent payments (variation margin) are made or received daily, in cash, by a fund. The variation margin is equal to the daily change in the contract value and is recorded as unrealized gains and losses. A fund recognizes a realized gain or loss when the contract is closed or expires. Net realized and unrealized gains or losses occurring during the holding period of futures contracts are a component of net realized gain (loss) on futures contract transactions and change in net unrealized appreciation (depreciation) on futures contracts, respectively. One of the risks of entering into futures contracts is the possibility that the change in value of the contract may not correlate with the changes in value of the underlying securities. During the period, the fund infrequently purchased equity price risk derivative instruments for temporary investment purposes.

Foreign Currency Risk — The fund is subject to foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The value of foreign investments held by a fund may be significantly affected by changes in foreign currency exchange rates. The dollar value of a foreign security generally decreases when the value of the dollar rises against the foreign currency in which the security is denominated and tends to increase when the value of the dollar declines against such foreign currency. A fund may enter into forward foreign currency exchange contracts to reduce a fund’s exposure to foreign currency exchange rate fluctuations. The net U.S. dollar value of foreign currency underlying all contractual commitments held by a fund and the resulting unrealized appreciation or depreciation are determined daily. Realized gain or loss is recorded upon the termination of the contract. Net realized and unrealized gains or losses occurring during the holding period of forward foreign currency exchange contracts are a component of net realized gain (loss) on foreign currency transactions and change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies, respectively. A fund bears the risk of an unfavorable change in the foreign currency exchange rate underlying the forward contract. Additionally, losses, up to the fair value, may arise if the counterparties do not perform under the contract terms. The risk of loss from non-performance by the counterparty may be reduced by the use of master netting agreements. The foreign currency risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

17

Value of Derivative Instruments as of April 30, 2011
	Asset Derivatives				Liability Derivatives
Type of Risk Exposure	Location on Statement of Assets and Liabilities	Value			Location on Statement of Assets and Liabilities	Value
Foreign Currency Risk	Unrealized gain on forward foreign currency exchange contracts		—		Unrealized loss on forward foreign currency exchange contracts	$	34,846
Effect of Derivative Instruments on the Statement of Operations for the Six Months Ended April 30, 2011
	Net Realized Gain (Loss)				Change in Net Unrealized Appreciation (Depreciation)
Type of Risk Exposure	Location on Statement of Operations	Value			Location on Statement of Operations	Value
Equity Price Risk	Net realized gain (loss) on futures contract transactions	$	293,119		Change in net unrealized appreciation (depreciation) on futures contracts		—
Foreign Currency Risk	Net realized gain (loss) on foreign currency transactions		(111,274	)	Change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies	$	(7,445	)
		$	181,845			$	(7,445	)

7. Risk Factors

There are certain risks involved in investing in foreign securities. These risks include those resulting from future adverse political, social, and economic developments, fluctuations in currency exchange rates, the possible imposition of exchange controls, and other foreign laws or restrictions.

The fund invests in common stocks of small companies. Because of this, it may be subject to greater risk and market fluctuations than a fund investing in larger, more established companies.

8. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	150,270,635
Gross tax appreciation of investments	$	53,083,807
Gross tax depreciation of investments		(434,008	)
Net tax appreciation (depreciation) of investments	$	52,649,799

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

18

As of October 31, 2010, the fund had accumulated capital losses of $(8,458,343), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers expire in 2017.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

19

Financial Highlights

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010				2009			2008			2007			2006(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	9.44		$	7.50		��	$	7.62		$	13.42		$	9.00		$	10.00
Income From Investment Operations
Net Investment    Income (Loss)		(0.01	)(3)		(0.02	)(3)			(0.02	)(3)		(0.04	)(3)		(0.04	)		(0.01	)
Net Realized and    Unrealized Gain (Loss)		1.93			1.96				(0.10	)		(5.73	)		4.46			(0.99	)
Total From    Investment Operations		1.92			1.94				(0.12	)		(5.77	)		4.42			(1.00	)
Distributions
From Net    Investment Income		—			—	(4)			—			—			—			—
From Net    Realized Gains		—			—				—			(0.03	)		—			—
Total Distributions		—			—	(4)			—			(0.03	)		—			—
Net Asset Value, End of Period	$	11.36		$	9.44			$	7.50		$	7.62		$	13.42		$	9.00
Total Return(5)		20.34	%		26.05	%			(1.71	)%		(43.09	)%		49.11	%		(10.00	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.80	%(6)		0.80	%			0.80	%		0.81	%		0.80	%		0.80	%(6)
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.24	)%(6)		(0.26	)%			(0.35	)%		(0.35	)%		(0.36	)%		(0.27	)%(6)
Portfolio Turnover Rate		55	%		152	%			190	%		183	%		147	%		109	%
Net Assets, End of Period (in thousands)	$	203,867		$	161,304			$	91,237		$	40,136		$	44,652		$	25,678

(1) Six months ended April 30, 2011 (unaudited).

(2) May 12, 2006 (fund inception) through October 31, 2006.

(3) Computed using average shares outstanding throughout the period.

(4) Per-share amount was less than $0.005.

(5) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(6) Annualized.

See Notes to Financial Statements.

20

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

21

Notes

22

Notes

23

Notes

24

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71845   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

Select Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	10
Statement of Operations	11
Statement of Changes in Net Assets	12
Notes to Financial Statements	13
Financial Highlights	19
Additional Information	25

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12–18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	10 years	Since Inception	Inception Date
Investor Class	TWCIX	16.84%	20.79%	4.39%	1.32%	12.36%	6/30/71(2)
Russell 1000 Growth Index	—	16.96%	20.87%	5.06%	2.11%	N/A(3)	—
Institutional Class	TWSIX	16.99%	21.03%	4.60%	1.54%	5.16%	3/13/97
A Class(4)    No sales charge*    With sales charge*	TWCAX	16.73% 10.03%	20.51% 13.58%	4.14% 2.91%	1.06% 0.47%	3.34% 2.89%	8/8/97
B Class    No sales charge*    With sales charge*	ABSLX	16.29% 11.29%	19.59% 15.59%	3.35% 3.17%	— —	5.52% 5.52%	1/31/03
C Class    No sales charge*    With sales charge*	ACSLX	16.27% 15.27%	19.60% 19.60%	3.35% 3.35%	— —	5.53% 5.53%	1/31/03
R Class	ASERX	16.56%	20.19%	3.87%	—	3.03%	7/29/05

*Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. B Class shares redeemed within six years of purchase are subject to a CDSC that declines from 5.00% during the first year after purchase to 0.00% the sixth year after purchase. C Class shares redeemed within 12 months of purchase are subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

(2) Although the fund’s actual inception date was 10/31/58, this inception date corresponds with the investment advisor’s implementation of its current investment philosophy and practices.

(3) Benchmark began 12/29/78.

(4) Prior to September 4, 2007, the A Class was referred to as the Advisor Class and did not have a front-end sales charge. Performance prior to that date has been adjusted to reflect this charge.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class	B Class	C Class	R Class
1.01%	0.81%	1.26%	2.01%	2.01%	1.51%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. International investing involves special risks, such as political instability and currency fluctuations.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Apple, Inc.	6.3%
Google, Inc., Class A	3.8%
Exxon Mobil Corp.	3.3%
Teradata Corp.	3.0%
EMC Corp.	2.7%
Coach, Inc.	2.5%
Costco Wholesale Corp.	2.5%
Occidental Petroleum Corp.	2.3%
UnitedHealth Group, Inc.	2.3%
Microsoft Corp.	2.3%
Top Five Industries	% of net assets
Computers & Peripherals	9.0%
Energy Equipment & Services	6.0%
Oil, Gas & Consumable Fuels	5.6%
Software	5.4%
Internet Software & Services	5.2%
Types of Investments in Portfolio	% of net assets
Domestic Common Stocks	90.9%
Foreign Common Stocks*	8.3%
Total Common Stocks	99.2%
Temporary Cash Investments	0.3%
Other Assets and Liabilities	0.5%
*Includes depositary shares, dual listed securities and foreign ordinary shares.

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,168.40	$5.38	1.00%
Institutional Class	$1,000	$1,169.90	$4.30	0.80%
A Class	$1,000	$1,167.30	$6.72	1.25%
B Class	$1,000	$1,162.90	$10.73	2.00%
C Class	$1,000	$1,162.70	$10.72	2.00%
R Class	$1,000	$1,165.60	$8.05	1.50%
Hypothetical
Investor Class	$1,000	$1,019.84	$5.01	1.00%
Institutional Class	$1,000	$1,020.83	$4.01	0.80%
A Class	$1,000	$1,018.60	$6.26	1.25%
B Class	$1,000	$1,014.88	$9.99	2.00%
C Class	$1,000	$1,014.88	$9.99	2.00%
R Class	$1,000	$1,017.36	$7.50	1.50%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 99.2%
AEROSPACE & DEFENSE — 3.7%
General Dynamics Corp.		515,100	$	37,509,582
Rockwell Collins, Inc.		570,000		35,967,000
				73,476,582
AIR FREIGHT & LOGISTICS — 1.4%
United Parcel Service, Inc., Class B		376,700		28,241,199
AUTO COMPONENTS — 0.8%
Johnson Controls, Inc.		364,500		14,944,500
BEVERAGES — 1.2%
Diageo plc		1,199,400		24,413,659
BIOTECHNOLOGY — 2.2%
Gilead Sciences, Inc.(1)		1,091,000		42,374,440
CAPITAL MARKETS — 2.3%
Bank of New York Mellon Corp. (The)		567,100		16,423,216
Franklin Resources, Inc.		221,300		28,574,256
				44,997,472
CHEMICALS — 3.1%
Monsanto Co.		508,700		34,611,948
Potash Corp. of Saskatchewan, Inc.		480,900		27,113,142
				61,725,090
COMMUNICATIONS EQUIPMENT — 2.9%
Cisco Systems, Inc.		1,064,000		18,683,840
QUALCOMM, Inc.		685,600		38,969,504
				57,653,344
COMPUTERS & PERIPHERALS — 9.0%
Apple, Inc.(1)		352,000		122,576,960
EMC Corp.(1)		1,880,700		53,299,038
				175,875,998
DIVERSIFIED FINANCIAL SERVICES — 2.8%
CME Group, Inc.		71,400		21,117,978
Hong Kong Exchanges and Clearing Ltd.		592,500		13,518,880
JPMorgan Chase & Co.		430,900		19,661,967
				54,298,825
ELECTRICAL EQUIPMENT — 3.9%
ABB Ltd. ADR(1)		1,178,400		32,394,216
Emerson Electric Co.		712,700		43,303,652
				75,697,868
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 0.5%
Dolby Laboratories, Inc., Class A(1)		207,303		10,377,588
ENERGY EQUIPMENT & SERVICES — 6.0%
Diamond Offshore Drilling, Inc.		217,000		16,463,790
Halliburton Co.		710,100		35,845,848
National Oilwell Varco, Inc.		356,800		27,362,992
Schlumberger Ltd.		428,300		38,439,925
				118,112,555
FOOD & STAPLES RETAILING — 2.7%
Costco Wholesale Corp.		596,500		48,268,780
Wal-Mart Stores, Inc.		71,500		3,931,070
				52,199,850
FOOD PRODUCTS — 2.0%
Hershey Co. (The)		301,700		17,411,107
Mead Johnson Nutrition Co.		339,000		22,672,320
				40,083,427
HEALTH CARE EQUIPMENT & SUPPLIES — 1.0%
Intuitive Surgical, Inc.(1)		58,000		20,282,600
HEALTH CARE PROVIDERS & SERVICES — 4.4%
Medco Health Solutions, Inc.(1)		700,115		41,537,823
UnitedHealth Group, Inc.		915,700		45,079,911
				86,617,734
HOTELS, RESTAURANTS & LEISURE — 2.1%
McDonald’s Corp.		450,700		35,294,317
Peet’s Coffee & Tea, Inc.(1)		138,400		6,432,832
				41,727,149
HOUSEHOLD DURABLES — 1.3%
Harman International Industries, Inc.		515,400		25,012,362
INSURANCE — 0.9%
Travelers Cos., Inc. (The)		263,300		16,661,624
INTERNET & CATALOG RETAIL — 3.1%
Amazon.com, Inc.(1)		173,400		34,073,100
Netflix, Inc.(1)		113,300		26,361,511
				60,434,611
INTERNET SOFTWARE & SERVICES — 5.2%
Baidu, Inc. ADR(1)		195,100		28,976,252
Google, Inc., Class A(1)		135,700		73,834,370
				102,810,622
IT SERVICES — 4.9%
Infosys Technologies Ltd. ADR		74,600		4,862,428
MasterCard, Inc., Class A		115,600		31,892,884
Teradata Corp.(1)		1,042,500		58,296,600
				95,051,912
LEISURE EQUIPMENT & PRODUCTS — 1.7%
Hasbro, Inc.		709,200		33,218,928

8

	Shares		Value
MACHINERY — 2.4%
Graco, Inc.	161,700	$	8,089,851
Parker-Hannifin Corp.	411,700		38,831,544
			46,921,395
METALS & MINING — 1.8%
Freeport-McMoRan Copper & Gold, Inc.	461,200		25,379,836
Walter Energy, Inc.	78,100		10,794,982
			36,174,818
OIL, GAS & CONSUMABLE FUELS — 5.6%
Exxon Mobil Corp.	732,800		64,486,400
Occidental Petroleum Corp.	395,500		45,201,695
			109,688,095
PHARMACEUTICALS — 3.2%
Allergan, Inc.	483,800		38,491,128
Teva Pharmaceutical Industries Ltd. ADR	509,800		23,313,154
			61,804,282
PROFESSIONAL SERVICES — 1.3%
IHS, Inc., Class A(1)	80,000		7,059,200
Robert Half International, Inc.	441,100		13,378,563
Verisk Analytics, Inc., Class A(1)	175,300		5,767,370
			26,205,133
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 2.4%
Linear Technology Corp.	1,089,300		37,907,640
NXP Semiconductor NV(1)	243,800		8,142,920
			46,050,560
SOFTWARE — 5.4%
Adobe Systems, Inc.(1)	546,400		18,331,720
Microsoft Corp.	1,728,700		44,980,774
Oracle Corp.	1,204,200		43,411,410
			106,723,904
SPECIALTY RETAIL — 2.1%
TJX Cos., Inc. (The)	749,500		40,188,190
TEXTILES, APPAREL & LUXURY GOODS — 4.0%
Coach, Inc.	817,300		48,882,713
Fossil, Inc.(1)	163,200		15,631,296
Hanesbrands, Inc.(1)	427,400		13,894,774
			78,408,783
TOBACCO — 1.6%
Philip Morris International, Inc.	452,200		31,400,768
WIRELESS TELECOMMUNICATION SERVICES — 0.3%
American Tower Corp., Class A(1)	101,300		5,299,003
TOTAL COMMON STOCKS (Cost $1,329,138,666)			1,945,154,870
Temporary Cash Investments — 0.3%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	62,411		62,411
Repurchase Agreement, Bank of America Securities, LLC, (collateralized by various U.S. Treasury obligations, 4.375%, 11/15/39, valued at $5,185,344), in a joint trading account at 0.02%, dated 4/29/11, due 5/2/11 (Delivery value $5,100,008)			5,100,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $5,162,411)			5,162,411
TOTAL INVESTMENT SECURITIES — 99.5% (Cost $1,334,301,077)			1,950,317,281
OTHER ASSETS AND LIABILITIES — 0.5%			10,013,711
TOTAL NET ASSETS — 100.0%		$	1,960,330,992

Forward Foreign Currency Exchange Contracts
Contracts to Sell		Counterparty	Settlement Date	Value	Unrealized Gain (Loss)
11,581,406	GBP for USD	Bank of America	5/31/11	$19,338,517	$(267,415)

(Value on Settlement Date $19,071,102)

Notes to Schedule of Investments

ADR = American Depositary Receipt

GBP = British Pound

USD = United States Dollar

(1) Non-income producing.

See Notes to Financial Statements.

9

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $1,334,301,077)	$	1,950,317,281
Cash		107,725
Foreign currency holdings, at value (cost of $342,180)		350,818
Receivable for investments sold		15,473,415
Receivable for capital shares sold		133,059
Dividends and interest receivable		1,249,918
		1,967,632,216
Liabilities
Payable for investments purchased		4,870,183
Payable for capital shares redeemed		581,175
Unrealized loss on forward foreign currency exchange contracts		267,415
Accrued management fees		1,576,070
Distribution and service fees payable		6,381
		7,301,224
Net Assets	$	1,960,330,992
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	1,523,063,563
Undistributed net investment income		1,739,448
Accumulated net realized loss		(180,231,064	)
Net unrealized appreciation		615,759,045
	$	1,960,330,992

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$1,929,500,310	46,615,502	$41.39
Institutional Class, $0.01 Par Value	$5,235,332	125,138	$41.84
A Class, $0.01 Par Value	$23,486,597	575,527	$40.81*
B Class, $0.01 Par Value	$1,653,849	42,201	$39.19
C Class, $0.01 Par Value	$388,869	9,912	$39.23
R Class, $0.01 Par Value	$66,035	1,612	$40.96
*Maximum offering price $43.30 (net asset value divided by 0.9425)

See Notes to Financial Statements.

10

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $21,910)	$	10,795,143
Interest		4,905
		10,800,048
Expenses:
Management fees		9,263,893
Distribution and service fees:
A Class		27,450
B Class		8,596
C Class		1,920
R Class		94
Directors’ fees and expenses		45,872
		9,347,825
Net investment income (loss)		1,452,223
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		36,081,443
Foreign currency transactions		(676,980	)
		35,404,463
Change in net unrealized appreciation (depreciation) on:
Investments		252,212,544
Translation of assets and liabilities in foreign currencies		33,749
		252,246,293
Net realized and unrealized gain (loss)		287,650,756
Net Increase (Decrease) in Net Assets Resulting from Operations	$	289,102,979

See Notes to Financial Statements.

11

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	1,452,223		$	5,682,049
Net realized gain (loss)		35,404,463			(20,615,057	)
Change in net unrealized appreciation (depreciation)		252,246,293			275,739,559
Net increase (decrease) in net assets resulting from operations		289,102,979			260,806,551
Distributions to Shareholders
From net investment income:
Investor Class		(5,930,231	)		(8,227,971	)
Institutional Class		(25,646	)		(28,810	)
A Class		(17,175	)		(49,312	)
Decrease in net assets from distributions		(5,973,052	)		(8,306,093	)
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		(72,360,667	)		(120,734,647	)
Net increase (decrease) in net assets		210,769,260			131,765,811
Net Assets
Beginning of period		1,749,561,732			1,617,795,921
End of period	$	1,960,330,992		$	1,749,561,732
Undistributed net investment income	$	1,739,448		$	6,260,277

See Notes to Financial Statements.

12

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Select Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by purchasing stocks of larger-sized companies that management believes will increase in value over time.

The fund is authorized to issue the Investor Class, the Institutional Class, the A Class, the B Class, the C Class and the R Class. The A Class may incur an initial sales charge. The A Class, B Class and C Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Forward foreign currency exchange contracts are valued at the mean of the latest bid and asked prices of the forward currency rates as provided by an independent pricing service.

The value of investments initially expressed in foreign currencies is translated into U.S. dollars at prevailing exchange rates.

13

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Foreign Currency Translations — All assets and liabilities initially expressed in foreign currencies are translated into U.S. dollars at prevailing exchange rates at period end. The fund may enter into spot foreign currency exchange contracts to facilitate transactions denominated in a foreign currency. Purchases and sales of investment securities, dividend and interest income, spot foreign currency exchange contracts, and expenses are translated at the rates of exchange prevailing on the respective dates of such transactions. Net realized and unrealized foreign currency exchange gains or losses related to investment securities are a component of net realized gain (loss) on investment transactions and change in net unrealized appreciation (depreciation) on investments, respectively.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

14

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The annual management fee schedule ranges from 0.800% to 1.000% for the Investor Class, A Class, B Class, C Class and R Class. The Institutional Class is 0.200% less at each point within the range. The effective annual management fee for each class for the six months ended April 30, 2011 was 1.00% for the Investor Class, A Class, B Class, C Class and R Class and 0.80% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a separate Master Distribution and Individual Shareholder Services Plan for each of the A Class, B Class, C Class and R Class (collectively the plans), pursuant to Rule 12b-1 of the 1940 Act. The plans provide that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The plans provide that the B Class and C Class will each pay ACIS an annual distribution and service fee of 1.00%, of which 0.25% is paid for individual shareholder services and 0.75% is paid for distribution services. The plans provide that the R Class will pay ACIS an annual distribution and service fee of 0.50%. The fees are computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services. Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a securities lending agreement with JPMorgan Chase Bank (JPMCB) and a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMCB is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $148,961,131 and $217,382,815, respectively.

15

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		300,000,000						300,000,000
Sold		738,366		$	28,573,634			1,050,151		$	34,737,773
Issued in reinvestment of distributions		150,876			5,677,451			238,915			7,886,605
Redeemed		(2,736,695	)		(105,572,010	)		(4,873,529	)		(160,602,909	)
		(1,847,453	)		(71,320,925	)		(3,584,463	)		(117,978,531	)
Institutional Class/Shares Authorized		40,000,000						40,000,000
Sold		13,016			516,492			22,888			771,300
Issued in reinvestment of distributions		670			25,466			851			28,366
Redeemed		(15,478	)		(625,531	)		(24,480	)		(817,754	)
		(1,792	)		(83,573	)		(741	)		(18,088	)
A Class/Shares Authorized		75,000,000						75,000,000
Sold		45,059			1,745,953			64,941			2,090,917
Issued in reinvestment of distributions		454			16,874			1,473			47,993
Redeemed		(60,605	)		(2,305,707	)		(134,115	)		(4,336,286	)
		(15,092	)		(542,880	)		(67,701	)		(2,197,376	)
B Class/Shares Authorized		25,000,000						25,000,000
Sold		1,073			40,615			925			27,964
Redeemed		(11,572	)		(425,659	)		(18,364	)		(576,033	)
		(10,499	)		(385,044	)		(17,439	)		(548,069	)
C Class/Shares Authorized		25,000,000						25,000,000
Sold		418			15,433			5,833			180,826
Redeemed		(2,066	)		(75,242	)		(5,028	)		(153,876	)
		(1,648	)		(59,809	)		805			26,950
R Class/Shares Authorized		50,000,000						50,000,000
Sold		882			34,696			72			2,323
Redeemed		(82	)		(3,132	)		(676	)		(21,856	)
		800			31,564			(604	)		(19,533	)
Net increase (decrease)		(1,875,684	)	$	(72,360,667	)		(3,670,143	)	$	(120,734,647	)

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

16

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2			Level 3
Investment Securities
Domestic Common Stocks	$	1,782,420,219		—			—
Foreign Common Stocks		124,802,112	$	37,932,539			—
Temporary Cash Investments		62,411		5,100,000			—
Total Value of Investment Securities	$	1,907,284,742	$	43,032,539			—
Other Financial Instruments
Total Unrealized Gain (Loss) on Forward Foreign Currency Exchange Contracts		—	$	(267,415	)		—

7. Derivative Instruments

Foreign Currency Risk — The fund is subject to foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The value of foreign investments held by a fund may be significantly affected by changes in foreign currency exchange rates. The dollar value of a foreign security generally decreases when the value of the dollar rises against the foreign currency in which the security is denominated and tends to increase when the value of the dollar declines against such foreign currency. A fund may enter into forward foreign currency exchange contracts to reduce a fund’s exposure to foreign currency exchange rate fluctuations. The net U.S. dollar value of foreign currency underlying all contractual commitments held by a fund and the resulting unrealized appreciation or depreciation are determined daily. Realized gain or loss is recorded upon the termination of the contract. Net realized and unrealized gains or losses occurring during the holding period of forward foreign currency exchange contracts are a component of net realized gain (loss) on foreign currency transactions and change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies, respectively. A fund bears the risk of an unfavorable change in the foreign currency exchange rate underlying the forward contract. Additionally, losses, up to the fair value, may arise if the counterparties do not perform under the contract terms. The risk of loss from non-performance by the counterparty may be reduced by the use of master netting agreements. The foreign currency risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

The value of foreign currency risk derivative instruments as of April 30, 2011, is disclosed on the Statement of Assets and Liabilities as a liability of $267,415 in unrealized loss on forward foreign currency exchange contracts. For the six months ended April 30, 2011, the effect of foreign currency risk derivative instruments on the Statement of Operations was $(700,556) in net realized gain (loss) on foreign currency transactions and $25,251 in change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies.

8. Risk Factors

There are certain risks involved in investing in foreign securities. These risks include those resulting from future adverse political, social, and economic developments, fluctuations in currency exchange rates, the possible imposition of exchange controls, and other foreign laws or restrictions.

17

9. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	1,338,322,101
Gross tax appreciation of investments	$	628,845,859
Gross tax depreciation of investments		(16,850,679	)
Net tax appreciation (depreciation) of investments	$	611,995,180

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(211,114,347), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers of $(14,707,162), $(175,918,131) and $(20,489,054) expire in 2016, 2017 and 2018, respectively.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

18

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	35.54		$	30.58		$	26.25		$	45.58		$	36.22		$	37.04
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.03			0.11			0.19			0.07			0.04			0.21
Net Realized and    Unrealized Gain (Loss)		5.94			5.01			4.40			(16.10	)		10.06			(0.77	)
Total From    Investment Operations		5.97			5.12			4.59			(16.03	)		10.10			(0.56	)
Distributions
From Net    Investment Income		(0.12	)		(0.16	)		(0.26	)		—			(0.16	)		(0.26	)
From Net    Realized Gains		—			—			—			(3.30	)		(0.58	)		—
Total Distributions		(0.12	)		(0.16	)		(0.26	)		(3.30	)		(0.74	)		(0.26	)
Net Asset Value, End of Period	$	41.39		$	35.54		$	30.58		$	26.25		$	45.58		$	36.22
Total Return(3)		16.84	%		16.78	%		17.77	%		(37.71	)%		28.37	%		(1.55	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.00	%(4)		1.01	%		1.00	%		1.00	%		1.00	%		1.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.16	%(4)		0.34	%		0.75	%		0.19	%		0.11	%		0.57	%
Portfolio Turnover Rate		8	%		35	%		31	%		64	%		79	%		206	%
Net Assets, End of Period (in millions)	$	1,930		$	1,722		$	1,592		$	1,449		$	2,550		$	2,576

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

19

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	35.95		$	30.94		$	26.56		$	45.98		$	36.53		$	37.35
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.07			0.18			0.28			0.15			0.12			0.30
Net Realized and    Unrealized Gain (Loss)		6.02			5.06			4.41			(16.27	)		10.15			(0.78	)
Total From    Investment Operations		6.09			5.24			4.69			(16.12	)		10.27			(0.48	)
Distributions
From Net    Investment Income		(0.20	)		(0.23	)		(0.31	)		—			(0.24	)		(0.34	)
From Net    Realized Gains		—			—			—			(3.30	)		(0.58	)		—
Total Distributions		(0.20	)		(0.23	)		(0.31	)		(3.30	)		(0.82	)		(0.34	)
Net Asset Value, End of Period	$	41.84		$	35.95		$	30.94		$	26.56		$	45.98		$	36.53
Total Return(3)		16.99	%		17.02	%		18.00	%		(37.60	)%		28.63	%		(1.35	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.80	%(4)		0.81	%		0.80	%		0.80	%		0.80	%		0.80	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.36	%(4)		0.54	%		0.95	%		0.39	%		0.31	%		0.77	%
Portfolio Turnover Rate		8	%		35	%		31	%		64	%		79	%		206	%
Net Assets, End of Period (in thousands)	$	5,235		$	4,563		$	3,950		$	94,419		$	168,441		$	148,717

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

20

A Class(1)
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(2)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	34.99		$	30.11		$	25.85		$	45.05		$	35.80		$	36.63
Income From Investment Operations
Net Investment    Income (Loss)(3)		(0.02	)		0.03			0.13			(0.02	)		(0.09	)		0.12
Net Realized and    Unrealized Gain (Loss)		5.87			4.93			4.33			(15.88	)		9.99			(0.76	)
Total From    Investment Operations		5.85			4.96			4.46			(15.90	)		9.90			(0.64	)
Distributions
From Net    Investment Income		(0.03	)		(0.08	)		(0.20	)		—			(0.07	)		(0.19	)
From Net    Realized Gains		—			—			—			(3.30	)		(0.58	)		—
Total Distributions		(0.03	)		(0.08	)		(0.20	)		(3.30	)		(0.65	)		(0.19	)
Net Asset Value, End of Period	$	40.81		$	34.99		$	30.11		$	25.85		$	45.05		$	35.80
Total Return(4)		16.73	%		16.48	%		17.47	%		(37.88	)%		28.07	%		(1.79	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.25	%(5)		1.26	%		1.25	%		1.25	%		1.25	%		1.25	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.09	)%(5)		0.09	%		0.50	%		(0.06	)%		(0.14	)%		0.32	%
Portfolio Turnover Rate		8	%		35	%		31	%		64	%		79	%		206	%
Net Assets, End of Period (in thousands)	$	23,487		$	20,666		$	19,824		$	19,450		$	42,770		$	21,455

(1) Prior to September 4, 2007, the A Class was referred to as the Advisor Class.

(2) Six months ended April 30, 2011 (unaudited).

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

21

B Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	33.70		$	29.15		$	25.03		$	44.03		$	35.21		$	36.12
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.15	)		(0.21	)		(0.06	)		(0.29	)		(0.34	)		(0.12	)
Net Realized and    Unrealized Gain (Loss)		5.64			4.76			4.20			(15.41	)		9.74			(0.79	)
Total From    Investment Operations		5.49			4.55			4.14			(15.70	)		9.40			(0.91	)
Distributions
From Net    Investment Income		—			—			(0.02	)		—			—			—
From Net    Realized Gains		—			—			—			(3.30	)		(0.58	)		—
Total Distributions		—			—			(0.02	)		(3.30	)		(0.58	)		—
Net Asset Value, End of Period	$	39.19		$	33.70		$	29.15		$	25.03		$	44.03		$	35.21
Total Return(3)		16.29	%		15.61	%		16.60	%		(38.36	)%		27.07	%		(2.52	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.00	%(4)		2.01	%		2.00	%		2.00	%		2.00	%		2.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.84	)%(4)		(0.66	)%		(0.25	)%		(0.81	)%		(0.89	)%		(0.43	)%
Portfolio Turnover Rate		8	%		35	%		31	%		64	%		79	%		206	%
Net Assets, End of Period (in thousands)	$	1,654		$	1,776		$	2,045		$	2,605		$	5,567		$	5,880

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

22

C Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	33.74		$	29.19		$	25.05		$	44.07		$	35.24		$	36.15
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.15	)		(0.20	)		(0.06	)		(0.29	)		(0.34	)		(0.16	)
Net Realized and    Unrealized Gain (Loss)		5.64			4.75			4.22			(15.43	)		9.75			(0.75	)
Total From    Investment Operations		5.49			4.55			4.16			(15.72	)		9.41			(0.91	)
Distributions
From Net    Investment Income		—			—			(0.02	)		—			—			—
From Net    Realized Gains		—			—			—			(3.30	)		(0.58	)		—
Total Distributions		—			—			(0.02	)		(3.30	)		(0.58	)		—
Net Asset Value, End of Period	$	39.23		$	33.74		$	29.19		$	25.05		$	44.07		$	35.24
Total Return(3)		16.27	%		15.63	%		16.58	%		(38.34	)%		27.07	%		(2.52	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.00	%(4)		2.01	%		2.00	%		2.00	%		2.00	%		2.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.84	)%(4)		(0.66	)%		(0.25	)%		(0.81	)%		(0.89	)%		(0.43	)%
Portfolio Turnover Rate		8	%		35	%		31	%		64	%		79	%		206	%
Net Assets, End of Period (in thousands)	$	389		$	390		$	314		$	394		$	1,001		$	1,540

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

23

R Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	35.14		$	30.24		$	25.96		$	45.33		$	36.05		$	37.00
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.06	)		(0.05	)		0.06			(0.11	)		(0.15	)		0.03
Net Realized and    Unrealized Gain (Loss)		5.88			4.95			4.36			(15.96	)		10.01			(0.77	)
Total From    Investment Operations		5.82			4.90			4.42			(16.07	)		9.86			(0.74	)
Distributions
From Net    Investment Income		—			—			(0.14	)		—			—			(0.21	)
From Net    Realized Gains		—			—			—			(3.30	)		(0.58	)		—
Total Distributions		—			—			(0.14	)		(3.30	)		(0.58	)		(0.21	)
Net Asset Value, End of Period	$	40.96		$	35.14		$	30.24		$	25.96		$	45.33		$	36.05
Total Return(3)		16.56	%		16.20	%		17.17	%		(38.03	)%		27.72	%		(2.04	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.50	%(4)		1.51	%		1.50	%		1.50	%		1.50	%		1.50	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.34	)%(4)		(0.16	)%		0.25	%		(0.31	)%		(0.39	)%		0.07	%
Portfolio Turnover Rate		8	%		35	%		31	%		64	%		79	%		206	%
Net Assets, End of Period (in thousands)	$	66		$	29		$	43		$	32		$	32		$	24

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

24

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

25

Notes

26

Notes

27

Notes

28

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71832   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

\

Small Cap Growth Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	12
Statement of Operations	13
Statement of Changes in Net Assets	14
Notes to Financial Statements	15
Financial Highlights	20
Additional Information	26

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year(2)	5 years	Since Inception	Inception Date
Investor Class	ANOIX	28.05%	32.87%	5.44%	8.43%	6/1/01
Russell 2000 Growth Index	—	27.07%	30.29%	5.14%	5.40%(3)	—
Institutional Class	ANONX	28.27%	33.06%	—	4.14%	5/18/07
A Class    No sales charge*    With sales charge*	ANOAX	28.03% 20.64%	32.54% 24.97%	5.18% 3.95%	12.46%       11.66%	1/31/03
B Class    No sales charge*    With sales charge*	ANOBX	27.46% 22.46%	31.54% 27.54%	4.40% 4.23%	11.63%       11.63%	1/31/03
C Class    No sales charge*    With sales charge*	ANOCX	27.35% 26.35%	31.40% 31.40%	4.38% 4.38%	11.66%(4)    11.66%(4)	1/31/03
R Class	ANORX	27.83%	32.16%	—	1.32%	9/28/07

* Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. B Class shares redeemed within six years of purchase are subject to a CDSC that declines from 5.00% during the first year after purchase to 0.00% the sixth year after purchase. C Class shares redeemed within 12 months of purchase are subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

(2) Extraordinary performance is attributable in part to unusually favorable market conditions and may not be repeated or consistently achieved in the future.

(3) Since 5/31/01, the date nearest the Investor Class’s inception for which data are available.

(4) Returns would have been lower if a portion of the distribution and service fees had not been waived.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class	B Class	C Class	R Class
1.42%	1.22%	1.67%	2.42%	2.42%	1.92%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. Historically, small company stocks have been more volatile than the stocks of larger, more established companies. The fund’s investment process may result in high portfolio turnover, which could mean high transaction costs, affecting both performance and capital gains tax liabilities to investors.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Tempur-Pedic International, Inc.	2.2%
Sauer-Danfoss, Inc.	1.9%
Titan International, Inc.	1.8%
Acme Packet, Inc.	1.6%
Sotheby’s	1.5%
Lindsay Corp.	1.4%
Iconix Brand Group, Inc.	1.4%
Pioneer Drilling Co.	1.3%
G-III Apparel Group Ltd.	1.2%
Polaris Industries, Inc.	1.2%
Top Five Industries	% of net assets
Machinery	10.5%
Software	6.8%
Semiconductors & Semiconductor Equipment	5.3%
Internet Software & Services	5.0%
Textiles, Apparel & Luxury Goods	4.4%
Types of Investments in Portfolio	% of net assets
Common Stocks	96.5%
Temporary Cash Investments	3.0%
Other Assets and Liabilities	0.5%

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,280.50	$7.86	1.39%
Institutional Class	$1,000	$1,282.70	$6.74	1.19%
A Class	$1,000	$1,280.30	$9.27	1.64%
B Class	$1,000	$1,274.60	$13.48	2.39%
C Class	$1,000	$1,273.50	$13.47	2.39%
R Class	$1,000	$1,278.30	$10.68	1.89%
Hypothetical
Investor Class	$1,000	$1,017.90	$6.95	1.39%
Institutional Class	$1,000	$1,018.89	$5.96	1.19%
A Class	$1,000	$1,016.66	$8.20	1.64%
B Class	$1,000	$1,012.94	$11.93	2.39%
C Class	$1,000	$1,012.94	$11.93	2.39%
R Class	$1,000	$1,015.42	$9.44	1.89%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 96.5%					��
AEROSPACE & DEFENSE — 0.9%
Triumph Group, Inc.		50,926	$	4,385,747
AIRLINES — 0.1%
United Continental Holdings, Inc.(1)		22,782		519,885
AUTO COMPONENTS — 0.9%
American Axle & Manufacturing Holdings, Inc.(1)		312,188		3,996,006
Amerigon, Inc.(1)		48,072		819,628
				4,815,634
BIOTECHNOLOGY — 3.9%
Acorda Therapeutics, Inc.(1)		31,327		878,409
Alkermes, Inc.(1)		27,662		398,886
AMAG Pharmaceuticals, Inc.(1)		21,444		407,436
ARIAD Pharmaceuticals, Inc.(1)		86,383		738,575
Cepheid, Inc.(1)		45,973		1,485,388
Cubist Pharmaceuticals, Inc.(1)		44,642		1,511,132
Geron Corp.(1)		103,271		495,701
ImmunoGen, Inc.(1)		55,559		742,268
Incyte Corp. Ltd.(1)		69,754		1,289,054
InterMune, Inc.(1)		37,321		1,666,009
Isis Pharmaceuticals, Inc.(1)		76,878		721,116
Micromet, Inc.(1)		80,091		541,415
Momenta Pharmaceuticals, Inc.(1)		36,552		689,736
Onyx Pharmaceuticals, Inc.(1)		47,642		1,789,910
PDL BioPharma, Inc.		112,684		723,431
Pharmasset, Inc.(1)		24,447		2,480,637
Savient Pharmaceuticals, Inc.(1)		60,786		705,725
Seattle Genetics, Inc.(1)		74,346		1,234,887
Theravance, Inc.(1)		53,346		1,480,352
				19,980,067
CAPITAL MARKETS — 0.8%
BGC Partners, Inc., Class A		162,311		1,566,301
HFF, Inc., Class A(1)		151,381		2,266,174
				3,832,475
CHEMICALS — 2.5%
Balchem Corp.		49,336		1,958,146
Flotek Industries, Inc.(1)		192,759		1,846,631
Intrepid Potash, Inc.(1)		115,363		3,952,336
OM Group, Inc.(1)		17,033		617,276
Solutia, Inc.(1)		174,030		4,585,691
				12,960,080
COMMERCIAL BANKS — 2.3%
Cathay General Bancorp.		185,007		3,154,369
Nara Bancorp., Inc.(1)		151,209		1,486,384
Pinnacle Financial Partners, Inc.(1)		121,571		1,953,646
PrivateBancorp, Inc.		88,534		1,393,525
Sandy Spring Bancorp, Inc.		28,987		517,998
Texas Capital Bancshares, Inc.(1)		70,977		1,831,207
West Coast Bancorp.(1)		370,835		1,327,589
				11,664,718
COMMERCIAL SERVICES & SUPPLIES — 1.1%
Deluxe Corp.		70,574		1,911,144
Steelcase, Inc., Class A		191,010		2,206,165
Team, Inc.(1)		65,664		1,638,317
				5,755,626
COMMUNICATIONS EQUIPMENT — 3.7%
Acme Packet, Inc.(1)		96,649		7,984,174
Finisar Corp.(1)		37,731		1,059,864
Netgear, Inc.(1)		61,930		2,585,577
Oplink Communications, Inc.(1)		126,146		2,497,691
Opnext, Inc.(1)		213,762		504,478
Riverbed Technology, Inc.(1)		99,492		3,496,149
Sycamore Networks, Inc.		20,927		512,712
				18,640,645
COMPUTERS & PERIPHERALS — 0.9%
Avid Technology, Inc.(1)		60,095		1,116,565
Stratasys, Inc.(1)		31,656		1,704,675
USA Technologies, Inc.(1)		544,046		1,653,900
				4,475,140
CONSTRUCTION MATERIALS — 0.3%
Headwaters, Inc.(1)		232,969		1,272,011
CONSUMER FINANCE — 1.3%
EZCORP, Inc., Class A(1)		78,177		2,461,794
World Acceptance Corp.(1)		63,135		4,290,023
				6,751,817
DIVERSIFIED CONSUMER SERVICES — 2.0%
K12, Inc.(1)		22,058		868,423
Sotheby’s		147,703		7,461,956
Steiner Leisure, Ltd.(1)		41,351		2,007,178
				10,337,557
DIVERSIFIED FINANCIAL SERVICES — 0.2%
Encore Capital Group, Inc.(1)		38,855		1,163,319

8

	Shares		Value
DIVERSIFIED TELECOMMUNICATION SERVICES — 0.3%
Vonage Holdings Corp.(1)	252,219	$	1,301,450
ELECTRICAL EQUIPMENT — 0.3%
Franklin Electric Co., Inc.	16,413		740,390
Valence Technology, Inc.(1)	399,228		542,950
			1,283,340
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 3.6%
Cognex Corp.	116,068		3,630,607
DDi Corp.	42,258		406,099
FARO Technologies, Inc.(1)	18,947		817,942
KEMET Corp.(1)	276,808		4,354,190
LeCroy Corp.(1)	87,500		1,142,750
Littelfuse, Inc.	89,397		5,561,387
Measurement Specialties, Inc.(1)	29,556		1,027,958
MTS Systems Corp.	26,199		1,159,830
			18,100,763
ENERGY EQUIPMENT & SERVICES — 4.1%
Basic Energy Services, Inc.(1)	156,572		4,813,023
Complete Production Services, Inc.(1)	121,791		4,133,587
Dawson Geophysical Co.(1)	27,116		1,209,374
Dril-Quip, Inc.(1)	5,250		401,940
Hornbeck Offshore Services, Inc.(1)	37,931		1,108,723
Matrix Service Co.(1)	108,843		1,573,870
North American Energy Partners, Inc.(1)	52,779		601,681
OYO Geospace Corp.(1)	9,073		846,329
Pioneer Drilling Co.(1)	414,729		6,428,299
			21,116,826
FOOD & STAPLES RETAILING — 1.7%
Andersons, Inc. (The)	90,447		4,490,693
PriceSmart, Inc.	101,489		4,226,002
			8,716,695
FOOD PRODUCTS — 0.6%
B&G Foods, Inc.	104,774		1,894,314
Omega Protein Corp.(1)	81,947		1,055,477
			2,949,791
HEALTH CARE EQUIPMENT & SUPPLIES — 4.1%
Abaxis, Inc.(1)	18,305		531,760
Align Technology, Inc.(1)	46,791		1,129,535
American Medical Systems Holdings, Inc.(1)	55,175		1,627,662
Arthrocare Corp.(1)	22,776		804,676
Cyberonics, Inc.(1)	23,956		852,115
DexCom, Inc.(1)	51,354		855,044
Haemonetics Corp.(1)	19,479		1,367,426
HeartWare International, Inc.(1)	7,902		589,568
Immucor, Inc.(1)	53,767		1,173,734
Insulet Corp.(1)	37,543		806,799
Integra LifeSciences Holdings Corp.(1)	17,163		897,797
Masimo Corp.	40,579		1,411,743
Meridian Bioscience, Inc.	32,684		807,622
Neogen Corp.(1)	18,855		790,025
NuVasive, Inc.(1)	32,568		1,006,026
Sirona Dental Systems, Inc.(1)	26,070		1,487,815
STERIS Corp.	43,261		1,559,126
Volcano Corp.(1)	41,881		1,116,547
West Pharmaceutical Services, Inc.	25,592		1,208,966
Zoll Medical Corp.(1)	17,406		986,572
			21,010,558
HEALTH CARE PROVIDERS & SERVICES — 2.3%
Amedisys, Inc.(1)	23,837		794,249
Bio-Reference Labs, Inc.(1)	20,638		520,284
Catalyst Health Solutions, Inc.(1)	28,980		1,726,049
Chemed Corp.	17,285		1,203,555
HealthSouth Corp.(1)	68,842		1,764,420
HMS Holdings Corp.(1)	21,052		1,657,003
Landauer, Inc.	8,381		504,285
MWI Veterinary Supply, Inc.(1)	10,423		866,881
Owens & Minor, Inc.	39,890		1,374,210
PSS World Medical, Inc.(1)	43,894		1,262,391
			11,673,327
HEALTH CARE TECHNOLOGY — 0.6%
athenahealth, Inc.(1)	26,023		1,203,043
MedAssets, Inc.(1)	36,423		583,497
Quality Systems, Inc.	14,692		1,318,166
			3,104,706
HOUSEHOLD DURABLES — 2.2%
Tempur-Pedic International, Inc.(1)	180,061		11,304,230
INDUSTRIAL CONGLOMERATES — 0.9%
Raven Industries, Inc.	83,146		4,519,817
INSURANCE — 0.7%
AMERISAFE, Inc.(1)	82,364		1,839,188
Amtrust Financial Services, Inc.	78,538		1,515,783
			3,354,971

9

Shares Value

INTERNET & CATALOG RETAIL — 0.8%
priceline.com, Inc.(1)	4,880	$	2,669,409
Shutterfly, Inc.(1)	24,825		1,528,227
			4,197,636
INTERNET SOFTWARE & SERVICES — 5.0%
Ancestry.com, Inc.(1)	65,547		2,995,498
Dice Holdings, Inc.(1)	286,770		5,256,494
Keynote Systems, Inc.	135,527		2,892,146
KIT Digital, Inc.(1)	29,526		339,844
Limelight Networks, Inc.(1)	71,198		453,531
Rackspace Hosting, Inc.(1)	72,453		3,346,604
Travelzoo, Inc.(1)	37,631		3,081,979
ValueClick, Inc.(1)	144,137		2,414,295
Vocus, Inc.(1)	137,183		4,064,732
Zix Corp.(1)	209,308		690,717
			25,535,840
IT SERVICES — 0.2%
MAXIMUS, Inc.	10,071		805,579
LEISURE EQUIPMENT & PRODUCTS — 1.2%
Polaris Industries, Inc.	55,772		5,880,042
LIFE SCIENCES TOOLS & SERVICES — 1.0%
Bruker Corp.(1)	56,922		1,123,640
Dionex Corp.(1)	13,870		1,641,515
Luminex Corp.(1)	33,770		654,800
PAREXEL International Corp.(1)	46,046		1,278,237
Sequenom, Inc.(1)	81,696		575,957
			5,274,149
MACHINERY — 10.5%
3D Systems Corp.(1)	38,426		1,603,133
Blount International, Inc.(1)	94,823		1,574,062
Cascade Corp.	51,810		2,372,898
CIRCOR International, Inc.	21,687		985,240
Commercial Vehicle Group, Inc.(1)	77,878		1,344,174
EnPro Industries, Inc.(1)	34,095		1,366,528
Graham Corp.	38,363		877,745
Kadant, Inc.(1)	41,214		1,271,452
Lindsay Corp.	96,117		7,047,299
Middleby Corp.(1)	35,528		3,185,796
NACCO Industries, Inc., Class A	14,024		1,475,746
NN, Inc.(1)	149,105		2,613,811
Robbins & Myers, Inc.	96,858		4,210,417
Sauer-Danfoss, Inc.(1)	167,129		9,862,282
Titan International, Inc.	297,134		9,178,469
Twin Disc, Inc.	34,404		1,172,144
Wabash National Corp.(1)	310,241		3,421,958
			53,563,154
MEDIA — 1.0%
MDC Partners, Inc., Class A	137,169		2,281,121
Sinclair Broadcast Group, Inc., Class A	222,564		2,557,260
			4,838,381
METALS & MINING — 2.7%
Allied Nevada Gold Corp.(1)	97,945		4,217,512
Globe Specialty Metals, Inc.	184,083		4,143,708
Materion Corp.(1)	83,421		3,483,661
Mesabi Royalty Trust	55,815		1,978,084
			13,822,965
OIL, GAS & CONSUMABLE FUELS — 4.1%
Crosstex Energy LP	155,381		3,070,328
Forest Oil Corp.(1)	38,229		1,372,803
Goodrich Petroleum Corp.(1)	99,494		2,235,630
Gulfport Energy Corp.(1)	114,519		3,898,227
Stone Energy Corp.(1)	104,394		3,691,372
W&T Offshore, Inc.	77,322		2,073,003
Western Refining, Inc.(1)	279,759		4,744,713
			21,086,076
PAPER & FOREST PRODUCTS — 1.6%
Buckeye Technologies, Inc.	143,619		4,044,311
KapStone Paper and Packaging Corp.(1)	230,296		4,002,544
			8,046,855
PHARMACEUTICALS — 1.2%
Auxilium Pharmaceuticals, Inc.(1)	33,381		813,161
Impax Laboratories, Inc.(1)	44,382		1,215,179
Nektar Therapeutics(1)	90,112		935,363
Questcor Pharmaceuticals, Inc.(1)	44,607		914,443
Salix Pharmaceuticals Ltd.(1)	44,433		1,745,773
VIVUS, Inc.(1)	70,092		545,316
			6,169,235
PROFESSIONAL SERVICES — 0.8%
Kelly Services, Inc., Class A(1)	222,873		4,259,103
REAL ESTATE INVESTMENT TRUSTS (REITs) — 1.6%
Ashford Hospitality Trust, Inc.	218,843		2,728,972
Lexington Realty Trust	88,171		879,947
Medical Properties Trust, Inc.	113,580		1,401,577
Post Properties, Inc.	82,573		3,352,464
			8,362,960

10

Shares Value

SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 5.3%
Amtech Systems, Inc.(1)	84,499	$	1,933,337
Cavium Networks, Inc.(1)	34,202		1,615,018
CEVA, Inc.(1)	70,324		2,150,508
Cirrus Logic, Inc.(1)	55,453		918,302
Entegris, Inc.(1)	298,572		2,576,676
FSI International, Inc.(1)	242,104		1,113,678
GSI Technology, Inc.(1)	123,057		1,096,438
GT Solar International, Inc.(1)	233,103		2,603,760
MIPS Technologies, Inc.(1)	36,712		305,444
Photronics, Inc.(1)	288,530		2,518,867
RF Micro Devices, Inc.(1)	127,963		852,234
Silicon Image, Inc.(1)	151,759		1,262,635
Skyworks Solutions, Inc.(1)	112,194		3,529,623
Ultratech, Inc.(1)	132,699		4,154,806
Veeco Instruments, Inc.(1)	7,836		400,655
			27,031,981
SOFTWARE — 6.8%
ACI Worldwide, Inc.(1)	64,795		2,140,827
Allot Communications Ltd.(1)	93,298		1,525,422
Ariba, Inc.(1)	50,671		1,761,831
Callidus Software, Inc.(1)	171,744		1,186,751
DemandTec, Inc.(1)	97,887		1,083,609
Fortinet, Inc.(1)	38,269		1,863,700
Glu Mobile, Inc.(1)	287,584		1,141,709
Interactive Intelligence, Inc.(1)	75,333		2,818,961
Kenexa Corp.(1)	190,530		5,605,393
Majesco Entertainment Co.(1)	445,597		1,670,989
Motricity, Inc.(1)	65,242		871,633
Opnet Technologies, Inc.	40,339		1,579,675
Progress Software Corp.(1)	63,733		1,889,683
PROS Holdings, Inc.(1)	91,096		1,428,385
Taleo Corp., Class A(1)	45,832		1,662,327
TIBCO Software, Inc.(1)	106,967		3,207,940
VASCO Data Security International, Inc.(1)	190,803		2,354,509
Websense, Inc.(1)	33,804		871,805
			34,665,149
SPECIALTY RETAIL — 2.2%
Charming Shoppes, Inc.(1)	331,419		1,501,328
Lithia Motors, Inc., Class A	269,359		4,899,640
Tractor Supply Co.	73,728		4,561,552
			10,962,520
TEXTILES, APPAREL & LUXURY GOODS — 4.4%
Crocs, Inc.(1)	90,806		1,826,109
Deckers Outdoor Corp.(1)	53,615		4,549,769
G-III Apparel Group Ltd.(1)	139,444		6,255,458
Iconix Brand Group, Inc.(1)	286,538		7,017,315
Oxford Industries, Inc.	60,284		2,070,755
Perry Ellis International, Inc.(1)	21,193		597,219
			22,316,625
TRADING COMPANIES & DISTRIBUTORS — 3.8%
CAI International, Inc.(1)	128,403		3,230,620
H&E Equipment Services, Inc.(1)	92,751		1,845,745
RSC Holdings, Inc.(1)	126,024		1,659,736
Rush Enterprises, Inc., Class A(1)	104,386		2,199,413
Titan Machinery, Inc.(1)	153,987		4,844,431
United Rentals, Inc.(1)	196,024		5,767,026
			19,546,971
TOTAL COMMON STOCKS (Cost $331,600,152)			491,356,416
Temporary Cash Investments — 3.0%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	70,104		70,104
Repurchase Agreement, Bank of America Securities, LLC, (collateralized by various U.S. Treasury obligations, 4.375%, 11/15/39, valued at $15,251,012), in a joint trading account at 0.02%, dated 4/29/11, due 5/2/11 (Delivery value $15,000,025)			15,000,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $15,070,104)			15,070,104
TOTAL INVESTMENT SECURITIES — 99.5% (Cost $346,670,256)			506,426,520
OTHER ASSETS AND LIABILITIES — 0.5%			2,519,045
TOTAL NET ASSETS — 100.0%		$	508,945,565

Notes to Schedule of Investments

(1) Non-income producing.

See Notes to Financial Statements.

11

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $346,670,256)	$	506,426,520
Receivable for investments sold		12,981,654
Receivable for capital shares sold		825,024
Dividends and interest receivable		117,309
		520,350,507
Liabilities
Payable for investments purchased		10,228,137
Payable for capital shares redeemed		598,007
Accrued management fees		532,189
Distribution and service fees payable		46,609
		11,404,942
Net Assets	$	508,945,565
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	637,621,056
Accumulated net investment loss		(1,782,371	)
Accumulated net realized loss		(286,649,384	)
Net unrealized appreciation		159,756,264
	$	508,945,565

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$199,352,861	20,891,796	$9.54
Institutional Class, $0.01 Par Value	$136,368,104	14,177,191	$9.62
A Class, $0.01 Par Value	$151,460,899	16,097,951	$9.41*
B Class, $0.01 Par Value	$3,305,391	365,340	$9.05
C Class, $0.01 Par Value	$16,971,541	1,868,415	$9.08
R Class, $0.01 Par Value	$1,486,769	158,666	$9.37

*Maximum offering price $9.98 (net asset value divided by 0.9425)

See Notes to Financial Statements.

12

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $1,922)	$	1,505,038
Interest		3,843
		1,508,881
Expenses:
Management fees		3,007,856
Distribution and service fees:
A Class		173,401
B Class		16,488
C Class		75,139
R Class		2,909
Directors’ fees and expenses		15,459
		3,291,252
Net investment income (loss)		(1,782,371	)
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on investment transactions		39,835,072
Change in net unrealized appreciation (depreciation) on investments		73,327,672
Net realized and unrealized gain (loss)		113,162,744
Net Increase (Decrease) in Net Assets Resulting from Operations	$	111,380,373

See Notes to Financial Statements.

13

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	(1,782,371	)	$	(2,176,343	)
Net realized gain (loss)		39,835,072			94,629,181
Change in net unrealized appreciation (depreciation)		73,327,672			36,489,688
Net increase (decrease) in net assets resulting from operations		111,380,373			128,942,526
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		(4,140,733	)		(135,018,924	)
Redemption Fees
Increase in net assets from redemption fees		55,395			185,421
Net increase (decrease) in net assets		107,295,035			(5,890,977	)
Net Assets
Beginning of period		401,650,530			407,541,507
End of period	$	508,945,565		$	401,650,530
Accumulated net investment loss	$	(1,782,371	)		—

See Notes to Financial Statements.

14

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Small Cap Growth Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing primarily in small cap companies that management believes will increase in value over time.

The fund is authorized to issue the Investor Class, the Institutional Class, the A Class, the B Class, the C Class and the R Class. The A Class may incur an initial sales charge. The A Class, B Class and C Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost.

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during

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the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Redemption — The fund may impose a 2.00% redemption fee on shares held less than 180 days. The fee may not be applicable to all classes. The redemption fee is retained by the fund and helps cover transaction costs that long-term investors may bear when the fund sells securities to meet investor redemptions.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

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3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The annual management fee schedule ranges from 1.10% to 1.50% for the Investor Class, A Class, B Class, C Class and R Class. The Institutional Class is 0.20% less at each point within the range. The effective annual management fee for each class for the six months ended April 30, 2011 was 1.39% for the Investor Class, A Class, B Class, C Class and R Class and 1.19% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a separate Master Distribution and Individual Shareholder Services Plan for each of the A Class, B Class, C Class and R Class (collectively the plans), pursuant to Rule 12b-1 of the 1940 Act. The plans provide that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The plans provide that the B Class and C Class will each pay ACIS an annual distribution and service fee of 1.00%, of which 0.25% is paid for individual shareholder services and 0.75% is paid for distribution services. The plans provide that the R Class will pay ACIS an annual distribution and service fee of 0.50%. The fees are computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services. Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMorgan Chase Bank (JPMCB) is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $234,102,105 and $247,577,839, respectively.

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5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		165,000,000						165,000,000
Sold		5,415,453		$	46,707,135			6,784,305		$	43,916,604
Redeemed		(3,695,490	)		(31,607,345	)		(18,735,868	)		(122,423,452	)
		1,719,963			15,099,790			(11,951,563	)		(78,506,848	)
Institutional Class/Shares Authorized		150,000,000						150,000,000
Sold		1,242,880			10,781,722			2,660,213			17,212,447
Redeemed		(2,333,000	)		(19,971,163	)		(7,096,717	)		(46,645,112	)
		(1,090,120	)		(9,189,441	)		(4,436,504	)		(29,432,665	)
A Class/Shares Authorized		110,000,000						110,000,000
Sold		1,419,930			12,015,621			2,350,237			15,349,838
Redeemed		(2,561,605	)		(21,506,875	)		(6,185,109	)		(39,950,252	)
		(1,141,675	)		(9,491,254	)		(3,834,872	)		(24,600,414	)
B Class/Shares Authorized		20,000,000						20,000,000
Sold		9,487			76,265			4,481			27,688
Redeemed		(81,905	)		(676,239	)		(132,247	)		(828,181	)
		(72,418	)		(599,974	)		(127,766	)		(800,493	)
C Class/Shares Authorized		20,000,000						20,000,000
Sold		251,922			2,070,199			413,664			2,630,469
Redeemed		(274,881	)		(2,234,437	)		(719,773	)		(4,536,633	)
		(22,959	)		(164,238	)		(306,109	)		(1,906,164	)
R Class/Shares Authorized		20,000,000						20,000,000
Sold		41,534			365,317			68,676			446,713
Redeemed		(18,993	)		(160,933	)		(33,289	)		(219,053	)
		22,541			204,384			35,387			227,660
Net increase (decrease)		(584,668	)	$	(4,140,733	)		(20,621,427	)	$	(135,018,924	)

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

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The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2		Level 3
Investment Securities
Common Stocks	$	491,356,416		—		—
Temporary Cash Investments		70,104	$	15,000,000		—
Total Value of Investment Securities	$	491,426,520	$	15,000,000		—

7. Risk Factors

The fund concentrates its investments in common stocks of small companies. Because of this, it may be subject to greater risk and market fluctuations than a fund investing in larger, more established companies.

The fund’s investment process may result in high portfolio turnover, which could mean high transaction costs, affecting both performance and capital gains tax liabilities to investors.

8. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	348,915,793
Gross tax appreciation of investments	$	161,309,191
Gross tax depreciation of investments		(3,798,464	)
Net tax appreciation (depreciation) of investments	$	157,510,727

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(324,687,779), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers expire as follows:

2014	2015	2016	2017
$(87,145,230)	—	$(125,173,360)	$(112,369,189)

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

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Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	7.45		$	5.47		$	5.57		$	9.42		$	7.63		$	6.75
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.03	)		(0.03	)		(0.02	)		(0.04	)		(0.05	)		(0.06	)
Net Realized and    Unrealized Gain (Loss)		2.12			2.01			(0.08	)		(3.73	)		2.52			1.16
Total From    Investment Operations		2.09			1.98			(0.10	)		(3.77	)		2.47			1.10
Distributions
From Net    Realized Gains		—			—			—			(0.08	)		(0.68	)		(0.22	)
Net Asset Value, End of Period	$	9.54		$	7.45		$	5.47		$	5.57		$	9.42		$	7.63
Total Return(3)		28.05	%		36.20	%		(1.80	)%		(40.34	)%		35.22	%		16.52	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.39	%(4)		1.42	%		1.41	%		1.36	%		1.41	%		1.50	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.72	)%(4)		(0.48	)%		(0.40	)%		(0.49	)%		(0.70	)%		(0.80	)%
Portfolio Turnover Rate		52	%		183	%		204	%		148	%		204	%		299	%
Net Assets, End of Period (in thousands)	$	199,353		$	142,793		$	170,125		$	222,017		$	303,189		$	51,336

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

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Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	7.50		$	5.49		$	5.59		$	9.43		$	8.27
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.02	)		(0.02	)		(0.01	)		(0.02	)		(0.03	)
Net Realized and Unrealized Gain (Loss)		2.14			2.03			(0.09	)		(3.74	)		1.19
Total From Investment Operations		2.12			2.01			(0.10	)		(3.76	)		1.16
Distributions
From Net Realized Gains		—			—			—			(0.08	)		—
Net Asset Value, End of Period	$	9.62		$	7.50		$	5.49		$	5.59		$	9.43
Total Return(4)		28.27	%		36.61	%		(1.79	)%		(40.19	)%		14.03	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.19	%(5)		1.22	%		1.21	%		1.16	%		1.21	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.52	)%(5)		(0.28	)%		(0.20	)%		(0.29	)%		(0.65	)%(5)
Portfolio Turnover Rate		52	%		183	%		204	%		148	%		204	%(6)
Net Assets, End of Period (in thousands)	$	136,368		$	114,513		$	108,261		$	91,791		$	18,384

(1) Six months ended April 30, 2011 (unaudited).

(2) May 18, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

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A Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	7.35		$	5.41		$	5.53		$	9.37		$	7.59		$	6.72
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.04	)		(0.05	)		(0.03	)		(0.06	)		(0.07	)		(0.08	)
Net Realized and    Unrealized Gain (Loss)		2.10			1.99			(0.09	)		(3.70	)		2.51			1.16
Total From    Investment Operations		2.06			1.94			(0.12	)		(3.76	)		2.44			1.08
Distributions
From Net    Realized Gains		—			—			—			(0.08	)		(0.66	)		(0.21	)
Net Asset Value, End of Period	$	9.41		$	7.35		$	5.41		$	5.53		$	9.37		$	7.59
Total Return(3)		28.03	%		35.86	%		(2.17	)%		(40.45	)%		34.91	%		16.22	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.64	%(4)		1.67	%		1.66	%		1.61	%		1.66	%		1.75	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.97	)%(4)		(0.73	)%		(0.65	)%		(0.74	)%		(0.95	)%		(1.05	)%
Portfolio Turnover Rate		52	%		183	%		204	%		148	%		204	%		299	%
Net Assets, End of Period (in thousands)	$	151,461		$	126,763		$	114,026		$	129,791		$	202,515		$	73,383

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

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B Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	7.10		$	5.26		$	5.41		$	9.25		$	7.49		$	6.63
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.07	)		(0.09	)		(0.07	)		(0.11	)		(0.13	)		(0.14	)
Net Realized and    Unrealized Gain (Loss)		2.02			1.93			(0.08	)		(3.65	)		2.49			1.15
Total From    Investment Operations		1.95			1.84			(0.15	)		(3.76	)		2.36			1.01
Distributions
From Net    Realized Gains		—			—			—			(0.08	)		(0.60	)		(0.15	)
Net Asset Value, End of Period	$	9.05		$	7.10		$	5.26		$	5.41		$	9.25		$	7.49
Total Return(3)		27.46	%		34.98	%		(2.77	)%		(40.97	)%		33.84	%		15.46	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.39	%(4)		2.42	%		2.41	%		2.36	%		2.41	%		2.50	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(1.72	)%(4)		(1.48	)%		(1.40	)%		(1.49	)%		(1.70	)%		(1.80	)%
Portfolio Turnover Rate		52	%		183	%		204	%		148	%		204	%		299	%
Net Assets, End of Period (in thousands)	$	3,305		$	3,107		$	2,976		$	2,846		$	4,549		$	3,383

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

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C Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	7.13		$	5.28		$	5.44		$	9.29		$	7.52		$	6.66
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.07	)		(0.09	)		(0.07	)		(0.11	)		(0.13	)		(0.14	)
Net Realized and    Unrealized Gain (Loss)		2.02			1.94			(0.09	)		(3.66	)		2.50			1.15
Total From    Investment Operations		1.95			1.85			(0.16	)		(3.77	)		2.37			1.01
Distributions
From Net    Realized Gains		—			—			—			(0.08	)		(0.60	)		(0.15	)
Net Asset Value, End of Period	$	9.08		$	7.13		$	5.28		$	5.44		$	9.29		$	7.52
Total Return(3)		27.35	%		35.04	%		(2.94	)%		(40.91	)%		34.02	%		15.24	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.39	%(4)		2.42	%		2.41	%		2.36	%		2.41	%		2.50	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(1.72	)%(4)		(1.48	)%		(1.40	)%		(1.49	)%		(1.70	)%		(1.80	)%
Portfolio Turnover Rate		52	%		183	%		204	%		148	%		204	%		299	%
Net Assets, End of Period (in thousands)	$	16,972		$	13,476		$	11,608		$	12,983		$	16,406		$	4,424

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

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R Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	7.33		$	5.41		$	5.54		$	9.42		$	9.02
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.05	)		(0.06	)		(0.06	)		(0.06	)		(0.01	)
Net Realized and Unrealized Gain (Loss)		2.09			1.98			(0.07	)		(3.74	)		0.41
Total From Investment Operations		2.04			1.92			(0.13	)		(3.80	)		0.40
Distributions
From Net Realized Gains		—			—			—			(0.08	)		—
Net Asset Value, End of Period	$	9.37		$	7.33		$	5.41		$	5.54		$	9.42
Total Return(4)		27.83	%		35.49	%		(2.35	)%		(40.66	)%		4.43	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.89	%(5)		1.92	%		1.91	%		1.86	%		1.91	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(1.22	)%(5)		(0.98	)%		(0.90	)%		(0.99	)%		(1.61	)%(5)
Portfolio Turnover Rate		52	%		183	%		204	%		148	%		204	%(6)
Net Assets, End of Period (in thousands)	$	1,487		$	998		$	545		$	108		$	26

(1) Six months ended April 30, 2011 (unaudited).

(2) September 28, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

25

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

26

Notes

27

Notes

28

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71843   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

Ultra® Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	10
Statement of Operations	11
Statement of Changes in Net Assets	12
Notes to Financial Statements	13
Financial Highlights	19
Additional Information	25

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	10 years	Since Inception	Inception Date
Investor Class	TWCUX	16.30%	20.74%	3.46%	2.00%	11.36%	11/2/81
Russell 1000 Growth Index	—	16.96%	20.87%	5.06%	2.11%	10.39%(2)	—
S&P 500 Index	—	16.36%	17.22%	2.95%	2.82%	11.48%(2)	—
Institutional Class	TWUIX	16.45%	20.97%	3.67%	2.21%	5.09%	11/14/96
A Class(3)	TWUAX						10/2/96
No sales charge*		16.20%	20.46%	3.20%	1.73%	4.88%
With sales charge*		9.51%	13.55%	1.99%	1.14%	4.45%
B Class	AULBX						9/28/07
No sales charge*		15.74%	19.54%	—	—	0.20%
With sales charge*		10.74%	15.54%	—	—	-0.64%
C Class	TWCCX						10/29/01
No sales charge*		15.73%	19.53%	2.43%	—	2.52%
With sales charge*		14.73%	19.53%	2.43%	—	2.52%
R Class	AULRX	16.02%	20.17%	2.94%	—	4.22%	8/29/03

*Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. B Class shares redeemed within six years of purchase are subject to a CDSC that declines from 5.00% during the first year after purchase to 0.00% the sixth year after purchase. C Class shares redeemed within 12 months of purchase are subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

(2) Since 10/31/81, the date nearest the Investor Class’s inception for which data are available.

(3) Prior to September 4, 2007, the A Class was referred to as the Advisor Class and did not have a front-end sales charge. Performance prior to that date has been adjusted to reflect this charge.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class	B Class	C Class	R Class
1.00%	0.80%	1.25%	2.00%	2.00%	1.50%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. International investing involves special risks, such as political instability and currency fluctuations.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the indices are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the indices do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Apple, Inc.	6.2%
Google, Inc., Class A	3.8%
Exxon Mobil Corp.	2.7%
Amazon.com, Inc.	2.6%
Schlumberger Ltd.	2.6%
Microsoft Corp.	2.3%
Express Scripts, Inc.	2.2%
Oracle Corp.	2.2%
QUALCOMM, Inc.	2.2%
Philip Morris International, Inc.	2.1%
Top Five Industries	% of net assets
Software	8.0%
Computers & Peripherals	7.9%
Oil, Gas & Consumable Fuels	6.9%
Machinery	6.4%
Electrical Equipment	5.8%
Types of Investments in Portfolio	% of net assets
Domestic Common Stocks	91.0%
Foreign Common Stocks*	8.5%
Total Common Stocks	99.5%
Temporary Cash Investments	0.3%
Other Assets and Liabilities	0.2%

*Includes depositary shares, dual listed securities and foreign ordinary shares.

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,163.00	$5.36	1.00%
Institutional Class	$1,000	$1,164.50	$4.29	0.80%
A Class	$1,000	$1,162.00	$6.70	1.25%
B Class	$1,000	$1,157.40	$10.70	2.00%
C Class	$1,000	$1,157.30	$10.70	2.00%
R Class	$1,000	$1,160.20	$8.03	1.50%
Hypothetical
Investor Class	$1,000	$1,019.84	$5.01	1.00%
Institutional Class	$1,000	$1,020.83	$4.01	0.80%
A Class	$1,000	$1,018.60	$6.26	1.25%
B Class	$1,000	$1,014.88	$9.99	2.00%
C Class	$1,000	$1,014.88	$9.99	2.00%
R Class	$1,000	$1,017.36	$7.50	1.50%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 99.5%
AEROSPACE & DEFENSE — 1.7%
General Dynamics Corp.		1,539,583	$	112,112,434
AUTO COMPONENTS — 0.5%
Gentex Corp.		1,077,000		33,763,950
BEVERAGES — 0.3%
Coca-Cola Co. (The)		306,000		20,642,760
BIOTECHNOLOGY — 3.6%
Alexion Pharmaceuticals, Inc.(1)		337,000		32,651,930
Celgene Corp.(1)		1,202,000		70,773,760
Gilead Sciences, Inc.(1)		3,522,000		136,794,480
				240,220,170
CAPITAL MARKETS — 0.8%
Charles Schwab Corp. (The)		2,932,000		53,684,920
CHEMICALS — 3.9%
Monsanto Co.		1,503,000		102,264,120
Nalco Holding Co.		2,020,000		59,004,200
Potash Corp. of Saskatchewan, Inc.		1,356,000		76,451,280
RPM International, Inc.		1,107,000		26,014,500
				263,734,100
COMMUNICATIONS EQUIPMENT — 3.2%
Cisco Systems, Inc.		4,009,000		70,398,040
QUALCOMM, Inc.		2,538,000		144,259,920
				214,657,960
COMPUTERS & PERIPHERALS — 7.9%
Apple, Inc.(1)		1,201,000		418,224,230
EMC Corp.(1)		3,843,000		108,910,620
				527,134,850
CONSUMER FINANCE — 1.0%
American Express Co.		1,341,000		65,816,280
DIVERSIFIED FINANCIAL SERVICES — 2.2%
CME Group, Inc.		270,000		79,857,900
JPMorgan Chase & Co.		1,500,000		68,445,000
				148,302,900
ELECTRICAL EQUIPMENT — 5.8%
ABB Ltd.(1)		1,756,000		48,477,781
ABB Ltd. ADR(1)		2,390,000		65,701,100
Cooper Industries plc		1,317,000		86,856,150
Emerson Electric Co.		2,221,000		134,947,960
Polypore International, Inc.(1)		858,673		53,040,231
				389,023,222
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 0.6%
Dolby Laboratories, Inc., Class A(1)		813,000		40,698,780
ENERGY EQUIPMENT & SERVICES — 3.7%
Cameron International Corp.(1)		1,079,000		56,884,880
Core Laboratories NV		215,000		20,635,700
Schlumberger Ltd.		1,911,000		171,512,250
				249,032,830
FOOD & STAPLES RETAILING — 2.2%
Costco Wholesale Corp.		1,612,000		130,443,040
Wal-Mart Stores, Inc.		244,000		13,415,120
				143,858,160
FOOD PRODUCTS — 2.6%
Hershey Co. (The)		994,000		57,363,740
Mead Johnson Nutrition Co.		630,763		42,185,430
Nestle SA		1,207,000		74,931,676
				174,480,846
HEALTH CARE EQUIPMENT & SUPPLIES — 2.3%
HeartWare International, Inc.(1)		122,332		9,127,190
Intuitive Surgical, Inc.(1)		275,000		96,167,500
Varian Medical Systems, Inc.(1)		684,000		48,016,800
				153,311,490
HEALTH CARE PROVIDERS & SERVICES — 3.7%
Express Scripts, Inc.(1)		2,643,000		149,963,820
Medco Health Solutions, Inc.(1)		175,899		10,436,088
UnitedHealth Group, Inc.		1,803,000		88,761,690
				249,161,598
HOTELS, RESTAURANTS & LEISURE — 3.0%
Chipotle Mexican Grill, Inc.(1)		131,000		34,949,490
McDonald’s Corp.		1,651,000		129,289,810
Starbucks Corp.		1,067,000		38,614,730
				202,854,030
INSURANCE — 1.5%
MetLife, Inc.		2,066,000		96,668,140
INTERNET & CATALOG RETAIL — 3.9%
Amazon.com, Inc.(1)		883,000		173,509,500
Netflix, Inc.(1)		368,000		85,622,560
				259,132,060
INTERNET SOFTWARE & SERVICES — 5.8%
Baidu, Inc. ADR(1)		545,844		81,068,751
Google, Inc., Class A(1)		469,000		255,182,900
Tencent Holdings Ltd.		1,835,000		52,217,608
				388,469,259
IT SERVICES — 1.8%
MasterCard, Inc., Class A		301,000		83,042,890
Teradata Corp.(1)		628,000		35,117,760
				118,160,650

8

	Shares		Value
LEISURE EQUIPMENT & PRODUCTS — 1.2%
Hasbro, Inc.	1,655,000	$	77,520,200
MACHINERY — 6.4%
Cummins, Inc.	575,000		69,103,500
Donaldson Co., Inc.	513,000		31,410,990
Joy Global, Inc.	1,253,000		126,490,350
Parker-Hannifin Corp.	1,062,000		100,167,840
WABCO Holdings, Inc.(1)	894,000		66,021,900
Wabtec Corp.	441,000		31,478,580
			424,673,160
METALS & MINING — 2.1%
BHP Billiton Ltd. ADR	520,000		52,644,800
Freeport-McMoRan Copper & Gold, Inc.	1,638,000		90,139,140
			142,783,940
MULTILINE RETAIL — 0.9%
Kohl’s Corp.	1,158,000		61,038,180
OIL, GAS & CONSUMABLE FUELS — 6.9%
EOG Resources, Inc.	601,000		67,858,910
Exxon Mobil Corp.	2,060,000		181,280,000
Newfield Exploration Co.(1)	939,000		66,481,200
Occidental Petroleum Corp.	1,058,000		120,918,820
Southwestern Energy Co.(1)	639,000		28,026,540
			464,565,470
PHARMACEUTICALS — 1.4%
Teva Pharmaceutical Industries Ltd. ADR	2,074,000		94,844,020
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 3.7%
Altera Corp.	1,905,000		92,773,500
Linear Technology Corp.	2,441,000		84,946,800
Microchip Technology, Inc.	1,721,000		70,629,840
			248,350,140
SOFTWARE — 8.0%
Adobe Systems, Inc.(1)	1,952,000		65,489,600
Electronic Arts, Inc.(1)	4,199,000		84,735,820
Microsoft Corp.	5,838,000		151,904,760
NetSuite, Inc.(1)	500,000		17,305,000
Oracle Corp.	4,052,000		146,074,600
salesforce.com, inc.(1)	105,000		14,553,000
VMware, Inc., Class A(1)	583,000		55,635,690
			535,698,470
SPECIALTY RETAIL — 3.6%
O’Reilly Automotive, Inc.(1)	763,000		45,062,780
Tiffany & Co.	1,455,000		101,035,200
TJX Cos., Inc. (The)	1,733,000		92,923,460
			239,021,440
TEXTILES, APPAREL & LUXURY GOODS — 1.2%
NIKE, Inc., Class B	1,010,000		83,143,200
TOBACCO — 2.1%
Philip Morris International, Inc.	2,055,000		142,699,200
TOTAL COMMON STOCKS (Cost $4,079,723,691)			6,659,258,809
Temporary Cash Investments — 0.3%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	66,888		66,888
Repurchase Agreement, Bank of America Securities, LLC, (collateralized by various U.S. Treasury obligations, 4.375%, 11/15/39, valued at $22,774,845), in a joint trading account at 0.02%, dated 4/29/11, due 5/2/11 (Delivery value $22,400,037)			22,400,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $22,466,888)			22,466,888
TOTAL INVESTMENT SECURITIES — 99.8% (Cost $4,102,190,579)			6,681,725,697
OTHER ASSETS AND LIABILITIES — 0.2%			13,053,633
TOTAL NET ASSETS — 100.0%		$	6,694,779,330

Forward Foreign Currency Exchange Contracts
Contracts to Sell		Counterparty	Settlement Date	Value	Unrealized Gain (Loss)
85,274,688	CHF for USD	Credit Suisse First Boston	5/31/11	$98,594,093	$(1,361,326)

(Value on Settlement Date $97,232,767)

Notes to Schedule of Investments

ADR = American Depositary Receipt

CHF = Swiss Franc

USD = United States Dollar

(1) Non-income producing.

See Notes to Financial Statements.

9

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $4,102,190,579)	$	6,681,725,697
Cash		375,000
Foreign currency holdings, at value (cost of $1,639,372)		1,677,939
Receivable for investments sold		34,769,822
Receivable for capital shares sold		1,467,227
Dividends and interest receivable		3,777,403
		6,723,793,088
Liabilities
Payable for investments purchased		17,627,561
Payable for capital shares redeemed		4,682,702
Unrealized loss on forward foreign currency exchange contracts		1,361,326
Accrued management fees		5,325,168
Distribution and service fees payable		17,001
		29,013,758
Net Assets	$	6,694,779,330
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	4,762,797,641
Undistributed net investment income		4,816,584
Accumulated net realized loss		(651,252,121	)
Net unrealized appreciation		2,578,417,226
	$	6,694,779,330

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$6,563,090,809	266,435,332	$24.63
Institutional Class, $0.01 Par Value	$53,679,601	2,133,142	$25.16
A Class, $0.01 Par Value	$72,824,338	3,039,224	$23.96*
B Class, $0.01 Par Value	$103,027	4,285	$24.04
C Class, $0.01 Par Value	$847,699	38,145	$22.22
R Class, $0.01 Par Value	$4,233,856	177,651	$23.83

*Maximum offering price $25.42 (net asset value divided by 0.9425)

See Notes to Financial Statements.

10

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $410,692)	$	36,726,800
Interest		18,745
		36,745,545
Expenses:
Management fees		31,414,634
Distribution and service fees:
A Class		87,078
B Class		506
C Class		4,065
R Class		9,110
Directors’ fees and expenses		157,257
		31,672,650
Net investment income (loss)		5,072,895
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		202,045,556
Foreign currency transactions		(9,398,048	)
		192,647,508
Change in net unrealized appreciation (depreciation) on:
Investments		766,830,868
Translation of assets and liabilities in foreign currencies		(1,478,270	)
		765,352,598
Net realized and unrealized gain (loss)		958,000,106
Net Increase (Decrease) in Net Assets Resulting from Operations	$	963,073,001

See Notes to Financial Statements.

11

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	5,072,895		$	14,027,620
Net realized gain (loss)		192,647,508			188,141,888
Change in net unrealized appreciation (depreciation)		765,352,598			836,699,181
Net increase (decrease) in net assets resulting from operations		963,073,001			1,038,868,689
Distributions to Shareholders
From net investment income:
Investor Class		(12,310,150	)		(26,725,188	)
Institutional Class		(189,254	)		(528,963	)
A Class		—			(172,872	)
Decrease in net assets from distributions		(12,499,404	)		(27,427,023	)
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		(280,004,895	)		(577,726,077	)
Net increase (decrease) in net assets		670,568,702			433,715,589
Net Assets
Beginning of period		6,024,210,628			5,590,495,039
End of period	$	6,694,779,330		$	6,024,210,628
Undistributed net investment income	$	4,816,584		$	12,243,093

See Notes to Financial Statements.

12

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Ultra Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing primarily in equity securities of large companies, but may invest in companies of any size.

The fund is authorized to issue the Investor Class, the Institutional Class, the A Class, the B Class, the C Class and the R Class. The A Class may incur an initial sales charge. The A Class, B Class and C Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Forward foreign currency exchange contracts are valued at the mean of the latest bid and asked prices of the forward currency rates as provided by an independent pricing service.

The value of investments initially expressed in foreign currencies is translated into U.S. dollars at prevailing exchange rates.

13

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Foreign Currency Translations — All assets and liabilities initially expressed in foreign currencies are translated into U.S. dollars at prevailing exchange rates at period end. The fund may enter into spot foreign currency exchange contracts to facilitate transactions denominated in a foreign currency. Purchases and sales of investment securities, dividend and interest income, spot foreign currency exchange contracts, and expenses are translated at the rates of exchange prevailing on the respective dates of such transactions. Net realized and unrealized foreign currency exchange gains or losses related to investment securities are a component of net realized gain (loss) on investment transactions and change in net unrealized appreciation (depreciation) on investments, respectively.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

14

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The annual management fee schedule ranges from 0.800% to 1.000% for the Investor Class, A Class, B Class, C Class and R Class. The Institutional Class is 0.200% less at each point within the range. The effective annual management fee for each class for the six months ended April 30, 2011 was 0.99% for the Investor Class, A Class, B Class, C Class and R Class and 0.79% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a separate Master Distribution and Individual Shareholder Services Plan for each of the A Class, B Class, C Class and R Class (collectively the plans), pursuant to Rule 12b-1 of the 1940 Act. The plans provide that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The plans provide that the B Class and

C Class will each pay ACIS an annual distribution and service fee of 1.00%, of which 0.25% is paid for individual shareholder services and 0.75% is paid for distribution services. The plans provide that the R Class will pay ACIS an annual distribution and service fee of 0.50%. The fees are computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services. Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a securities lending agreement with JPMorgan Chase Bank (JPMCB) and a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMCB is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $431,331,899 and $714,745,633, respectively.

15

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		3,500,000,000						3,500,000,000
Sold		4,312,176		$	99,744,820			8,040,692		$	157,299,128
Issued in reinvestment of distributions		530,036			11,936,500			1,335,312			25,958,465
Redeemed		(16,793,612	)		(386,825,899	)		(35,922,123	)		(700,572,950	)
		(11,951,400	)		(275,144,579	)		(26,546,119	)		(517,315,357	)
Institutional Class/Shares Authorized		200,000,000						200,000,000
Sold		268,405			6,374,910			729,074			14,762,326
Issued in reinvestment of distributions		8,231			189,232			25,921			514,529
Redeemed		(254,307	)		(6,036,155	)		(2,701,567	)		(53,218,916	)
		22,329			527,987			(1,946,572	)		(37,942,061	)
A Class/Shares Authorized		100,000,000						100,000,000
Sold		311,255			7,023,669			534,148			10,123,675
Issued in reinvestment of distributions		—			—			8,809			166,840
Redeemed		(574,798	)		(12,774,208	)		(1,712,426	)		(32,190,650	)
		(263,543	)		(5,750,539	)		(1,169,469	)		(21,900,135	)
B Class/Shares Authorized		50,000,000						50,000,000
Sold		—			—			6			112
Redeemed		(686	)		(15,486	)		—			—
		(686	)		(15,486	)		6			112
C Class/Shares Authorized		50,000,000						50,000,000
Sold		4,344			92,590			3,687			64,700
Redeemed		(7,320	)		(151,240	)		(17,068	)		(301,317	)
		(2,976	)		(58,650	)		(13,381	)		(236,617	)
R Class/Shares Authorized		50,000,000						50,000,000
Sold		29,983			683,289			41,073			780,064
Redeemed		(11,054	)		(246,917	)		(59,405	)		(1,112,083	)
		18,929			436,372			(18,332	)		(332,019	)
Net increase (decrease)		(12,177,347	)	$	(280,004,895	)		(29,693,867	)	$	(577,726,077	)

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

16

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2			Level 3
Investment Securities
Domestic Common Stocks	$	6,092,286,093		—			—
Foreign Common Stocks		391,345,651	$	175,627,065			—
Temporary Cash Investments		66,888		22,400,000			—
Total Value of Investment Securities	$	6,483,698,632	$	198,027,065			—
Other Financial Instruments
Total Unrealized Gain (Loss) on Forward Foreign Currency Exchange Contracts		—	$	(1,361,326	)		—

7. Derivative Instruments

Foreign Currency Risk — The fund is subject to foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The value of foreign investments held by a fund may be significantly affected by changes in foreign currency exchange rates. The dollar value of a foreign security generally decreases when the value of the dollar rises against the foreign currency in which the security is denominated and tends to increase when the value of the dollar declines against such foreign currency. A fund may enter into forward foreign currency exchange contracts to reduce a fund’s exposure to foreign currency exchange rate fluctuations. The net U.S. dollar value of foreign currency underlying all contractual commitments held by a fund and the resulting unrealized appreciation or depreciation are determined daily. Realized gain or loss is recorded upon the termination of the contract. Net realized and unrealized gains or losses occurring during the holding period of forward foreign currency exchange contracts are a component of net realized gain (loss) on foreign currency transactions and change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies, respectively. A fund bears the risk of an unfavorable change in the foreign currency exchange rate underlying the forward contract. Additionally, losses, up to the fair value, may arise if the counterparties do not perform under the contract terms. The risk of loss from non-performance by the counterparty may be reduced by the use of master netting agreements. The foreign currency risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

The value of foreign currency risk derivative instruments as of April 30, 2011, is disclosed on the Statement of Assets and Liabilities as a liability of $1,361,326 in unrealized loss on forward foreign currency exchange contracts. For the six months ended April 30, 2011, the effect of foreign currency risk derivative instruments on the Statement of Operations was $(9,475,781) in net realized gain (loss) on foreign currency transactions and $(1,595,410) in change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies.

8. Risk Factors

There are certain risks involved in investing in foreign securities. These risks include those resulting from future adverse political, social, and economic developments, fluctuations in currency exchange rates, the possible imposition of exchange controls, and other foreign laws or restrictions.

17

9. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	4,161,380,052
Gross tax appreciation of investments	$	2,542,376,059
Gross tax depreciation of investments		(22,030,414	)
Net tax appreciation (depreciation) of investments	$	2,520,345,645

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

As of October 31, 2010, the fund had accumulated capital losses of $(782,228,557), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers of $(35,695,674) and $(746,532,883) expire in 2016 and 2017, respectively.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

18

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	21.22		$	17.82		$	15.67		$	33.48		$	28.55		$	29.02
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.02			0.05			0.11			0.08			(0.01	)		(0.06	)
Net Realized and    Unrealized Gain (Loss)		3.43			3.44			2.12			(9.95	)		6.95			(0.37	)
Total From    Investment Operations		3.45			3.49			2.23			(9.87	)		6.94			(0.43	)
Distributions
From Net    Investment Income		(0.04	)		(0.09	)		(0.08	)		—			—			(0.04	)
From Net    Realized Gains		—			—			—			(7.94	)		(2.01	)		—
Total Distributions		(0.04	)		(0.09	)		(0.08	)		(7.94	)		(2.01	)		(0.04	)
Net Asset Value, End of Period	$	24.63		$	21.22		$	17.82		$	15.67		$	33.48		$	28.55
Total Return(3)		16.30	%		19.63	%		14.35	%		(38.02	)%		25.89	%		(1.51	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.00	%(4)		1.00	%		1.00	%		0.99	%		0.99	%		0.99	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.16	%(4)		0.25	%		0.69	%		0.36	%		(0.04	)%		(0.15	)%
Portfolio Turnover Rate		7	%		24	%		53	%		152	%		93	%		62	%
Net Assets, End of Period (in millions)	$	6,563		$	5,906		$	5,435		$	5,276		$	10,066		$	13,482

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

19

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	21.69		$	18.22		$	16.02		$	33.98		$	28.90		$	29.38
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.04			0.09			0.14			0.15			0.05			—	(3)
Net Realized and    Unrealized Gain (Loss)		3.52			3.51			2.17			(10.17	)		7.04			(0.38	)
Total From    Investment Operations		3.56			3.60			2.31			(10.02	)		7.09			(0.38	)
Distributions
From Net    Investment Income		(0.09	)		(0.13	)		(0.11	)		—			—			(0.10	)
From Net    Realized Gains		—			—			—			(7.94	)		(2.01	)		—
Total Distributions		(0.09	)		(0.13	)		(0.11	)		(7.94	)		(2.01	)		(0.10	)
Net Asset Value, End of Period	$	25.16		$	21.69		$	18.22		$	16.02		$	33.98		$	28.90
Total Return(4)		16.45	%		19.81	%		14.58	%		(37.89	)%		26.14	%		(1.33	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.80	%(5)		0.80	%		0.80	%		0.79	%		0.79	%		0.79	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.36	%(5)		0.45	%		0.89	%		0.56	%		0.16	%		0.05	%
Portfolio Turnover Rate		7	%		24	%		53	%		152	%		93	%		62	%
Net Assets, End of Period (in thousands)	$	53,680		$	45,791		$	73,933		$	76,339		$	325,035		$	1,073,767

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Per-share amount was less than $0.005.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

20

A Class(1)
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(2)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	20.62		$	17.33		$	15.23		$	32.83		$	28.11		$	28.61
Income From Investment Operations
Net Investment    Income (Loss)(3)		(0.01	)		—	(4)		0.07			0.03			(0.08	)		(0.13	)
Net Realized and    Unrealized Gain (Loss)		3.35			3.33			2.07			(9.69	)		6.81			(0.37	)
Total From    Investment Operations		3.34			3.33			2.14			(9.66	)		6.73			(0.50	)
Distributions
From Net    Investment Income		—			(0.04	)		(0.04	)		—			—			—
From Net    Realized Gains		—			—			—			(7.94	)		(2.01	)		—
Total Distributions		—			(0.04	)		(0.04	)		(7.94	)		(2.01	)		—
Net Asset Value, End of Period	$	23.96		$	20.62		$	17.33		$	15.23		$	32.83		$	28.11
Total Return(5)		16.20	%		19.24	%		14.14	%		(38.19	)%		25.56	%		(1.75	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.25	%(6)		1.25	%		1.25	%		1.24	%		1.24	%		1.24	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.09	)%(6)		0.00	%(7)		0.44	%		0.11	%		(0.29	)%		(0.40	)%
Portfolio Turnover Rate		7	%		24	%		53	%		152	%		93	%		62	%
Net Assets, End of Period (in thousands)	$	72,824		$	68,109		$	77,484		$	85,723		$	235,217		$	405,173

(1) Prior to September 4, 2007, the A Class was referred to as the Advisor Class.

(2) Six months ended April 30, 2011 (unaudited).

(3) Computed using average shares outstanding throughout the period.

(4) Per-share amount was less than $0.005.

(5) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(6) Annualized.

(7) Ratio was less than 0.005%.

See Notes to Financial Statements.

21

B Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	20.77		$	17.54		$	15.49		$	33.45		$	31.63
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.09	)		(0.15	)		(0.06	)		(0.16	)		(0.04	)
Net Realized and Unrealized Gain (Loss)		3.36			3.38			2.11			(9.86	)		1.86
Total From Investment Operations		3.27			3.23			2.05			(10.02	)		1.82
Distributions
From Net Realized Gains		—			—			—			(7.94	)		—
Net Asset Value, End of Period	$	24.04		$	20.77		$	17.54		$	15.49		$	33.45
Total Return(4)		15.74	%		18.42	%		13.23	%		(38.64	)%		5.75	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.00	%(5)		2.00	%		2.00	%		1.99	%		1.99	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.84	)%(5)		(0.75	)%		(0.31	)%		(0.64	)%		(1.53	)%(5)
Portfolio Turnover Rate		7	%		24	%		53	%		152	%		93	%(6)
Net Assets, End of Period (in thousands)	$	103		$	103		$	87		$	41		$	26

(1) Six months ended April 30, 2011 (unaudited).

(2) September 28, 2007 (commencement of sale) through October 31, 2007.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2007.

See Notes to Financial Statements.

22

C Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	19.20		$	16.22		$	14.32		$	31.54		$	27.26		$	27.96
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.09	)		(0.13	)		(0.04	)		(0.13	)		(0.29	)		(0.34	)
Net Realized and    Unrealized Gain (Loss)		3.11			3.11			1.94			(9.15	)		6.58			(0.36	)
Total From    Investment Operations		3.02			2.98			1.90			(9.28	)		6.29			(0.70	)
Distributions
From Net    Realized Gains		—			—			—			(7.94	)		(2.01	)		—
Net Asset Value, End of Period	$	22.22		$	19.20		$	16.22		$	14.32		$	31.54		$	27.26
Total Return(3)		15.73	%		18.45	%		13.20	%		(38.63	)%		24.64	%		(2.50	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.00	%(4)		2.00	%		2.00	%		1.99	%		1.99	%		1.99	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.84	)%(4)		(0.75	)%		(0.31	)%		(0.64	)%		(1.04	)%		(1.15	)%
Portfolio Turnover Rate		7	%		24	%		53	%		152	%		93	%		62	%
Net Assets, End of Period (in thousands)	$	848		$	789		$	884		$	891		$	2,129		$	3,342

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

23

R Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	20.54		$	17.26		$	15.17		$	32.80		$	28.15		$	28.72
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.04	)		(0.05	)		0.03			(0.03	)		(0.15	)		(0.21	)
Net Realized and    Unrealized Gain (Loss)		3.33			3.33			2.07			(9.66	)		6.81			(0.36	)
Total From    Investment Operations		3.29			3.28			2.10			(9.69	)		6.66			(0.57	)
Distributions
From Net    Investment Income		—			—			(0.01	)		—			—			—
From Net    Realized Gains		—			—			—			(7.94	)		(2.01	)		—
Total Distributions		—			—			(0.01	)		(7.94	)		(2.01	)		—
Net Asset Value, End of Period	$	23.83		$	20.54		$	17.26		$	15.17		$	32.80		$	28.15
Total Return(3)		16.02	%		19.00	%		13.84	%		(38.35	)%		25.26	%		(1.98	)%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.50	%(4)		1.50	%		1.50	%		1.49	%		1.49	%		1.49	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.34	)%(4)		(0.25	)%		0.19	%		(0.14	)%		(0.54	)%		(0.65	)%
Portfolio Turnover Rate		7	%		24	%		53	%		152	%		93	%		62	%
Net Assets, End of Period (in thousands)	$	4,234		$	3,260		$	3,056		$	3,276		$	5,971		$	8,922

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

24

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

25

Notes

26

Notes

27

Notes

28

 

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71839   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

Veedot® Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	11
Statement of Operations	12
Statement of Changes in Net Assets	13
Notes to Financial Statements	14
Financial Highlights	19
Additional Information	21

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12-18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	10 years	Since Inception	Inception Date
Investor Class	AMVIX	17.74%	16.11%	0.71%	2.98%	2.58%	11/30/99
Russell 3000 Index	—	17.65%	18.35%	3.33%	3.64%	2.56%	—
Institutional Class	AVDIX	17.84%	16.23%	0.90%	3.16%	1.02%	8/1/00

(1) Total returns for periods less than one year are not annualized.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class
1.26%	1.06%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. The fund’s investment process may result in high portfolio turnover, which could mean high transaction costs, affecting both performance and capital gains tax liabilities to investors. International investing involves special risks, such as political instability and currency fluctuations. Investing in emerging markets may accentuate these risks.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
CenterPoint Energy, Inc.	2.4%
Hormel Foods Corp.	2.2%
Pinnacle West Capital Corp.	2.1%
Wal-Mart Stores, Inc.	2.0%
United States Cellular Corp.	2.0%
NuStar Energy LP	2.0%
Endurance Specialty Holdings Ltd.	1.9%
UGI Corp.	1.7%
Alliance Resource Partners, LP	1.6%
Humana, Inc.	1.5%
Top Five Industries	% of net assets
Oil, Gas & Consumable Fuels	16.5%
Insurance	9.4%
Food & Staples Retailing	6.5%
Health Care Providers & Services	5.4%
Media	4.4%
Types of Investments in Portfolio	% of net assets
Domestic Common Stocks	89.2%
Foreign Common Stocks*	10.9%
Total Common Stocks	100.1%
Other Assets and Liabilities	(0.1)%
* Includes depositary shares, dual listed securities and foreign ordinary shares.

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,177.40	$6.75	1.25%
Institutional Class	$1,000	$1,178.40	$5.67	1.05%
Hypothetical
Investor Class	$1,000	$1,018.60	$6.26	1.25%
Institutional Class	$1,000	$1,019.59	$5.26	1.05%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 100.1%
AEROSPACE & DEFENSE — 2.0%
L-3 Communications Holdings, Inc.		10,500	$	841,995
Lockheed Martin Corp.		10,877		862,002
				1,703,997
AIR FREIGHT & LOGISTICS — 1.2%
Forward Air Corp.		29,659		997,136
AIRLINES — 1.0%
SkyWest, Inc.		50,049		827,310
AUTO COMPONENTS — 0.1%
Goodyear Tire & Rubber Co. (The)(1)		3,150		57,172
BEVERAGES — 2.1%
Coca-Cola Co. (The)		12,999		876,913
PepsiCo, Inc.		13,132		904,663
				1,781,576
CAPITAL MARKETS — 0.2%
Fortress Investment Group LLC, Class A(1)		21,665		133,673
CHEMICALS — 1.0%
Ecolab, Inc.		16,695		880,828
COMMERCIAL SERVICES & SUPPLIES — 1.0%
Pitney Bowes, Inc.		35,500		871,880
COMMUNICATIONS EQUIPMENT — 0.3%
Nokia Oyj ADR		30,077		277,611
CONTAINERS & PACKAGING — 1.1%
Ball Corp.		25,000		932,750
DISTRIBUTORS — 1.0%
Genuine Parts Co.		15,500		832,350
DIVERSIFIED TELECOMMUNICATION SERVICES — 1.1%
Telecomunicacoes de Sao Paulo SA ADR		34,500		935,295
ELECTRIC UTILITIES — 3.7%
Northeast Utilities		13,215		470,454
Pinnacle West Capital Corp.		42,000		1,822,380
UniSource Energy Corp.		23,000		853,990
				3,146,824
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 1.1%
National Instruments Corp.		31,500		955,710
FOOD & STAPLES RETAILING — 6.5%
Costco Wholesale Corp.		12,000		971,040
Kroger Co. (The)		36,384		884,495
Safeway, Inc.		37,500		911,625
Walgreen Co.		24,000		1,025,280
Wal-Mart Stores, Inc.		31,500		1,731,870
				5,524,310
FOOD PRODUCTS — 3.6%
B&G Foods, Inc.		66,500		1,202,320
Hormel Foods Corp.		65,000		1,911,650
				3,113,970
GAS UTILITIES — 3.7%
AGL Resources, Inc.		1,089		45,204
Atmos Energy Corp.		26,500		924,585
ONEOK, Inc.		10,049		702,827
UGI Corp.		44,000		1,465,200
				3,137,816
HEALTH CARE EQUIPMENT & SUPPLIES — 2.1%
Baxter International, Inc.		16,009		910,912
Immucor, Inc.(1)		40,942		893,764
				1,804,676
HEALTH CARE PROVIDERS & SERVICES — 5.4%
Cardinal Health, Inc.		20,758		906,917
Chemed Corp.		12,742		887,225
Humana, Inc.(1)		17,000		1,294,040
LifePoint Hospitals, Inc.(1)		11,872		493,994
UnitedHealth Group, Inc.		20,000		984,600
				4,566,776
HOTELS, RESTAURANTS & LEISURE — 2.5%
Cracker Barrel Old Country Store, Inc.		18,100		927,263
McDonald’s Corp.		5,095		398,990
Papa John’s International, Inc.(1)		26,554		798,213
				2,124,466
HOUSEHOLD PRODUCTS — 1.0%
WD-40 Co.		21,107		875,941
INDEPENDENT POWER PRODUCERS & ENERGY TRADERS — 0.3%
AES Corp. (The)(1)		22,370		296,179
INDUSTRIAL CONGLOMERATES — 1.0%
General Electric Co.		42,431		867,714
INSURANCE — 9.4%
American Financial Group, Inc.		25,500		912,135
Arthur J. Gallagher & Co.		28,405		845,901
Axis Capital Holdings Ltd.		23,000		813,280
Endurance Specialty Holdings Ltd.		36,000		1,596,240
Montpelier Re Holdings Ltd.		7,376		133,432
Principal Financial Group, Inc.		26,802		904,567
Reinsurance Group of America, Inc.		14,500		917,850

8

	Shares		Value
Safety Insurance Group, Inc.	18,385	$	860,786
Torchmark Corp.	15,000		1,003,800
			7,987,991
INTERNET SOFTWARE & SERVICES — 1.0%
j2 Global Communications, Inc.(1)	30,000		883,800
IT SERVICES — 2.8%
Global Payments, Inc.	11,484		611,408
International Business Machines Corp.	5,330		909,191
ManTech International Corp., Class A(1)	20,211		887,061
			2,407,660
MACHINERY — 1.8%
Dover Corp.	15,500		1,054,620
IDEX Corp.	11,006		516,402
			1,571,022
MEDIA — 4.4%
Charter Communications, Inc., Class A(1)	15,538		915,810
John Wiley & Sons, Inc., Class A	18,500		942,205
Sinclair Broadcast Group, Inc., Class A	105,500		1,212,195
Washington Post Co. (The), Class B	1,596		695,696
			3,765,906
METALS & MINING — 2.1%
Freeport-McMoRan Copper & Gold, Inc.	16,000		880,480
Rio Tinto plc ADR	13,000		951,730
			1,832,210
MULTILINE RETAIL — 1.0%
Kohl’s Corp.	15,965		841,515
MULTI-UTILITIES — 2.5%
CenterPoint Energy, Inc.	110,000		2,046,000
SCANA Corp.	1,500		62,280
			2,108,280
OIL, GAS & CONSUMABLE FUELS — 16.5%
Alliance Resource Partners, LP	17,000		1,400,120
Buckeye Partners LP	13,500		878,310
Calumet Specialty Products Partners LP	40,280		889,382
ConocoPhillips	2,224		175,540
Energy Transfer Partners LP	16,567		899,920
Enterprise Products Partners LP	20,500		887,035
Genesis Energy, LP	40,000		1,116,800
Holly Energy Partners LP	15,195		832,534
NuStar Energy LP	24,500		1,661,345
Plains Exploration & Production Co.(1)	24,417		928,823
Sunoco Logistics Partners LP	10,000		900,300
Targa Resources Partners LP	25,000		878,500
TC PipeLines LP	16,782		811,913
Teekay Offshore Partners LP	30,500		941,535
TransMontaigne Partners LP	23,462		846,040
			14,048,097
PHARMACEUTICALS — 4.3%
Abbott Laboratories	17,218		896,025
AstraZeneca plc ADR	18,362		914,978
Eli Lilly & Co.	25,000		925,250
Novo Nordisk A/S ADR	7,500		955,425
			3,691,678
REAL ESTATE INVESTMENT TRUSTS (REITs) — 1.2%
Rayonier, Inc.	15,000		995,400
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 3.9%
Analog Devices, Inc.	22,500		906,975
Intel Corp.	25,620		594,128
Taiwan Semiconductor Manufacturing Co. Ltd. ADR	69,653		940,315
Texas Instruments, Inc.	25,500		906,015
			3,347,433
SPECIALTY RETAIL — 1.0%
PetSmart, Inc.	21,000		885,570
TOBACCO — 2.2%
Altria Group, Inc.	32,648		876,272
Lorillard, Inc.	9,307		991,196
			1,867,468
WIRELESS TELECOMMUNICATION SERVICES — 3.0%
NTT DOCOMO, Inc. ADR	47,739		883,649
United States Cellular Corp.(1)	34,500		1,698,780
			2,582,429
TOTAL INVESTMENT SECURITIES — 100.1% (Cost $77,918,968)			85,462,419
OTHER ASSETS AND LIABILITIES — (0.1)%			(124,099	)
TOTAL NET ASSETS — 100.0%		$	85,338,320

9

Geographic Diversification
(as a % of net assets)
United States	89.2%
Bermuda	3.0%
United Kingdom	2.2%
Denmark	1.1%
Bahamas	1.1%
Taiwan (Republic of China)	1.1%
Brazil	1.1%
Japan	1.0%
Finland	0.3%
Other Assets and Liabilities	(0.1)%

Notes to Schedule of Investments

ADR = American Depositary Receipt

(1) Non-income producing.

See Notes to Financial Statements.

10

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $77,918,968)	$	85,462,419
Receivable for investments sold		241,354
Receivable for capital shares sold		5,698
Dividends and interest receivable		237,767
		85,947,238
Liabilities
Disbursements in excess of demand deposit cash		468,019
Payable for capital shares redeemed		53,664
Accrued management fees		87,235
		608,918
Net Assets	$	85,338,320
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	108,737,384
Undistributed net investment income		218,954
Accumulated net realized loss		(31,161,469	)
Net unrealized appreciation		7,543,451
	$	85,338,320

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$82,790,417	12,402,077	$6.68
Institutional Class, $0.01 Par Value	$2,547,903	375,130	$6.79

See Notes to Financial Statements.

11

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends	$	846,627
Interest		479
		847,106
Expenses:
Management fees		520,213
Directors’ fees and expenses		2,061
		522,274
Net investment income (loss)		324,832
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on investment transactions		19,441,352
Change in net unrealized appreciation (depreciation) on investments		(6,038,213	)
Net realized and unrealized gain (loss)		13,403,139
Net Increase (Decrease) in Net Assets Resulting from Operations	$	13,727,971

See Notes to Financial Statements.

12

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	324,832		$	(39,074	)
Net realized gain (loss)		19,441,352			8,472,692
Change in net unrealized appreciation (depreciation)		(6,038,213	)		6,795,479
Net increase (decrease) in net assets resulting from operations		13,727,971			15,229,097
Distributions to Shareholders
From net investment income:
Investor Class		(95,981	)		(48,886	)
Institutional Class		(9,897	)		(8,309	)
Decrease in net assets from distributions		(105,878	)		(57,195	)
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		(9,706,894	)		(12,443,945	)
Redemption Fees
Increase in net assets from redemption fees		1,059			2,579
Net increase (decrease) in net assets		3,916,258			2,730,536
Net Assets
Beginning of period		81,422,062			78,691,526
End of period	$	85,338,320		$	81,422,062
						��
Undistributed net investment income	$	218,954			—

See Notes to Financial Statements.

13

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Veedot Fund (the fund) is one fund in a series issued by the corporation. The fund is nondiversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing primarily in common stocks that management believes to have better than average prospects for appreciation. The fund uses an approach to common stock investing developed by American Century Investments. This approach relies heavily on quantitative tools to identify attractive investment opportunities, regardless of company size, industry type or geographic location, on a disciplined, consistent basis.

The fund is authorized to issue the Investor Class and the Institutional Class. The share classes differ principally in their respective distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost.

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited

14

to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Distributions received on securities that represent a return of capital or capital gain are recorded as a reduction of cost of investments and/or as a realized gain. The fund estimates the components of distributions received that may be considered nontaxable distributions or capital gain distributions for income tax purposes. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Redemption — The fund may impose a 2.00% redemption fee on shares held less than 180 days. The fee may not be applicable to all classes. The redemption fee is retained by the fund and helps cover transaction costs that long-term investors may bear when the fund sells securities to meet investor redemptions.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

15

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The rate of the fee is determined by applying a fee rate calculation formula. This formula takes into account the fund’s assets as well as certain assets, if any, of other clients of the investment advisor outside the American Century Investments family of funds (such as subadvised funds and separate accounts) that have very similar investment teams and investment strategies (strategy assets). The annual management fee schedule ranges from 1.000% to 1.250% for the Investor Class. The Institutional Class is 0.200% less at each point within the range. The effective annual management fee for each class for the six months ended April 30, 2011 was 1.25% and 1.05% for the Investor Class and Institutional Class, respectively.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, American Century Investment Services, Inc., and the corporation’s transfer agent, American Century Services, LLC.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMorgan Chase Bank (JPMCB) is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $105,065,972 and $110,802,536, respectively.

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		200,000,000						200,000,000
Sold		281,851		$	1,715,948			394,054		$	2,119,491
Issued in reinvestment of distributions		15,435			93,224			8,820			47,717
Redeemed		(1,710,428	)		(10,575,379	)		(2,645,725	)		(13,942,170	)
		(1,413,142	)		(8,766,207	)		(2,242,851	)		(11,774,962	)
Institutional Class/Shares Authorized		100,000,000						100,000,000
Sold		25,118			159,661			24,836			134,114
Issued in reinvestment of distributions		1,612			9,897			1,511			8,309
Redeemed		(167,120	)		(1,110,245	)		(155,132	)		(811,406	)
		(140,390	)		(940,687	)		(128,785	)		(668,983	)
Net increase (decrease)		(1,553,532	)	$	(9,706,894	)		(2,371,636	)	$	(12,443,945	)

16

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2		Level 3
Investment Securities
Domestic Common Stocks	$	76,118,929		—		—
Foreign Common Stocks		9,343,490		—		—
Total Value of Investment Securities	$	85,462,419		—		—

7. Risk Factors

The fund’s investment process may result in high portfolio turnover, which could mean high transaction costs, affecting both performance and capital gains tax liabilities to investors.

There are certain risks involved in investing in foreign securities. These risks include those resulting from future adverse political, social, and economic developments, fluctuations in currency exchange rates, the possible imposition of exchange controls, and other foreign laws or restrictions. Investing in emerging markets may accentuate these risks.

17

8. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	77,918,968
Gross tax appreciation of investments	$	7,839,785
Gross tax depreciation of investments		(296,334	)
Net tax appreciation (depreciation) of investments	$	7,543,451

The cost of investments for federal income tax purposes was the same as the cost for financial reporting purposes.

As of October 31, 2010, the fund had accumulated capital losses of $(50,661,212), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers of $(27,976,449) and $(22,684,763) expire in 2016 and 2017, respectively.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

18

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	5.68		$	4.71		$	5.34		$	9.25		$	6.17		$	5.57
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.02			—	(3)		—	(3)		(0.02	)		(0.01	)		(0.02	)
Net Realized and    Unrealized Gain (Loss)		0.99			0.97			(0.63	)		(3.89	)		3.09			0.62
Total From    Investment Operations		1.01			0.97			(0.63	)		(3.91	)		3.08			0.60
Distributions
From Net    Investment Income		(0.01	)		—	(3)		—			—			—			—
Net Asset Value, End of Period	$	6.68		$	5.68		$	4.71		$	5.34		$	9.25		$	6.17
Total Return(4)		17.74	%		20.66	%		(11.80	)%		(42.27	)%		49.92	%		10.77	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.25	%(5)		1.26	%		1.25	%		1.25	%		1.25	%		1.45	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.77	%(5)		(0.06	)%		(0.03	)%		(0.27	)%		(0.18	)%		(0.39	)%
Portfolio Turnover Rate		126	%		260	%		320	%		257	%		207	%		330	%
Net Assets, End of Period (in thousands)	$	82,790		$	78,441		$	75,603		$	98,991		$	195,105		$	154,374

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Per-share amount was less than $0.005.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

19

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	5.78		$	4.79		$	5.43		$	9.38		$	6.25		$	5.63
Income From Investment Operations
Net Investment    Income (Loss)(2)		0.03			0.01			0.01			(0.01	)		—	(3)		(0.01	)
Net Realized and    Unrealized Gain (Loss)		1.00			0.99			(0.65	)		(3.94	)		3.13			0.63
Total From    Investment Operations		1.03			1.00			(0.64	)		(3.95	)		3.13			0.62
Distributions
From Net    Investment Income		(0.02	)		(0.01	)		—			—			—			—
Net Asset Value, End of Period	$	6.79		$	5.78		$	4.79		$	5.43		$	9.38		$	6.25
Total Return(4)		17.84	%		20.97	%		(11.79	)%		(42.11	)%		50.08	%		11.01	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.05	%(5)		1.06	%		1.05	%		1.05	%		1.05	%		1.25	%
Ratio of Net Investment Income (Loss) to Average Net Assets		0.97	%(5)		0.14	%		0.17	%		(0.07	)%		0.02	%		(0.19	)%
Portfolio Turnover Rate		126	%		260	%		320	%		257	%		207	%		330	%
Net Assets, End of Period (in thousands)	$	2,548		$	2,981		$	3,089		$	4,864		$	9,188		$	11,237

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Per-share amount was less than $0.005.

(4) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

20

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

21

Notes

22

Notes

23

Notes

24

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71840   1106

SEMIANNUAL REPORT      |      APRIL 30, 2011

VistaSM Fund

Table of Contents

President’s Letter	2
Independent Chairman’s Letter	3
Performance	4
Fund Characteristics	5
Shareholder Fee Example	6
Schedule of Investments	8
Statement of Assets and Liabilities	11
Statement of Operations	12
Statement of Changes in Net Assets	13
Notes to Financial Statements	14
Financial Highlights	21
Additional Information	26

Any opinions expressed in this report reflect those of the author as of the date of the report, and do not necessarily represent the opinions of American Century Investments® or any other person in the American Century Investments organization. Any such opinions are subject to change at any time based upon market or other conditions and American Century Investments disclaims any responsibility to update such opinions. These opinions may not be relied upon as investment advice and, because investment decisions made by American Century Investments funds are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any American Century Investments fund. Security examples are used for representational purposes only and are not intended as recommendations to purchase or sell securities. Performance information for comparative indices and securities is provided to American Century Investments by third party vendors. To the best of American Century Investments’ knowledge, such information is accurate at the time of printing.

1

President’s Letter

Jonathan Thomas

Dear Investor:

Thank you for reviewing our semiannual report for the six months ended April 30, 2011. This report offers a macroeconomic and U.S. financial market overview of the period (below), followed by fund performance, a schedule of fund investments, and other financial information.

For additional, updated information on fund performance, portfolio strategy, and the investment markets, we encourage you to visit our website, americancentury.com. Click on the “Fund Performance” and “Insights & News” headings at the top of our Individual Investors site. Also, the fund’s annual report, dated October 31, 2011, will provide additional market perspective and portfolio commentary from our portfolio management team.

Macroeconomic and U.S. Financial Market Overview

Benefitting from favorable conditions that may be difficult to replicate in coming months, the U.S. stock market produced significantly higher than average returns for the six months ended April 30, 2011. Most broad U.S. stock indices gained 15–20% during the period as the Federal Reserve’s and the U.S. government’s monetary and fiscal intervention in 2010 stimulated growth and fueled investor optimism about economic and financial market conditions in 2011 and 2012. Robust corporate earnings growth also supported the stock rally.

In the fourth quarter of 2010, the Federal Reserve launched its second round of quantitative easing (QE2), a form of monetary intervention involving the purchase of U.S. government securities to increase the money supply and encourage investors to purchase potentially higher-risk/higher-return assets, such as stocks. Small-cap growth stocks benefited most from the resulting rally, though their larger-cap and value counterparts also posted sizeable gains.

As the period came to a close, we saw increasing signs that—while still sustainable—the U.S. economic recovery had lost momentum due to a combination of higher fuel prices, disruptions caused by the Japanese earthquake, bad weather, and other headwinds. As a result, economic growth forecasts were reduced, and broad U.S. stock indices declined in May. We appreciate your continued trust in us during these uncertain times. The stock experts who manage our U.S. Growth Equity portfolios will continue to diligently apply their knowledge and skills as they make daily investment decisions for you.

Sincerely,

Jonathan Thomas

President and Chief Executive Officer

American Century Investments

2

Independent Chairman’s Letter

Don Pratt

Dear Fellow Shareholders,

With an existing vacancy and several directors approaching retirement age over the next few years, your American Century Investments Kansas City-based mutual fund board of directors recently addressed board succession planning. The board developed a succession plan and conducted an extensive search that yielded two new members who will join the board in 2011.

As part of the planning process, the board referred to the criteria for potential new directors set forth in its director nomination policy adopted in 2009. A nomination process generated more than 20 candidates whose credentials were reviewed by the board’s Governance Committee. Six candidates were selected by the committee for telephone interviews. Three were then chosen for in person interviews.

The committee recommended, and the full board approved, the addition of Jan Lewis, currently the President and Chief Executive Officer of Catholic Charities of Northeast Kansas, to fill the vacant board seat and the addition as an advisory director of Stephen E. Yates, who recently retired as Executive Vice President, Technology and Operations at Keycorp of Cleveland, Ohio. Mr. Yates will serve in an advisory capacity for 12–18 months before becoming an active director. Both of these additions bring operating management experience and unique perspectives to our various tasks.

We look forward to the contributions of our new directors to our efforts as shareholder representatives and thank the Governance Committee for their thorough search process.

If you have comments, suggestions or questions send them to me at dhpratt@fundboardchair.com.

Best regards,

Don Pratt

3

Performance

Total Returns as of April 30, 2011
				Average Annual Returns
	Ticker Symbol	6 months(1)	1 year	5 years	10 years	Since Inception	Inception Date
Investor Class	TWCVX	20.00%	24.49%	2.63%	4.30%	9.54%	11/25/83
Russell Midcap Growth Index	—	22.62%	27.40%	5.59%	5.68%	N/A(2)	—
Institutional Class	TWVIX	20.17%	24.78%	2.83%	4.52%	5.96%	11/14/96
A Class(3)    No sales charge*    With sales charge*	TWVAX	19.85% 12.96%	24.23% 17.07%	2.38% 1.17%	4.02% 3.41%	4.95% 4.52%	10/2/96
C Class    No sales charge*    With sales charge*	AVNCX	19.41% 18.41%	23.23% 23.23%	— —	— —	26.72%   26.72%	3/1/10
R Class	AVTRX	19.74%	23.92%	2.13%	—	4.49%	7/29/05

*Sales charges include initial sales charges and contingent deferred sales charges (CDSCs), as applicable. A Class shares have a 5.75% maximum initial sales charge and may be subject to a maximum CDSC of 1.00%. C Class shares redeemed within 12 months of purchase are subject to a maximum CDSC of 1.00%. The SEC requires that mutual funds provide performance information net of maximum sales charges in all cases where charges could be applied.

(1) Total returns for periods less than one year are not annualized.

(2) Index data not available prior to 12/31/85.

(3) Prior to March 1, 2010, the A Class was referred to as the Advisor Class and did not have a front-end sales charge. Performance prior to that date has been adjusted to reflect this charge.

Total Annual Fund Operating Expenses
Investor Class	Institutional Class	A Class	C Class	R Class
1.01%	0.81%	1.26%	2.01%	1.51%

The total annual fund operating expenses shown is as stated in the fund’s prospectus current as of the date of this report. The prospectus may vary from the expense ratio shown elsewhere in this report because it is based on a different time period, includes acquired fund fees and expenses, and, if applicable, does not include fee waivers or expense reimbursements.

Data presented reflect past performance. Past performance is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment return and principal value will fluctuate, and redemption value may be more or less than original cost. To obtain performance data current to the most recent month end, please call 1-800-345-2021 or visit americancentury.com. International investing involves special risks, such as political instability and currency fluctuations. Historically, small company stocks have been more volatile than the stocks of larger, more established companies.

Unless otherwise indicated, performance reflects Investor Class shares; performance for other share classes will vary due to differences in fee structure. For information about other share classes available, please consult the prospectus. Data assumes reinvestment of dividends and capital gains, and none of the charts reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Returns for the index are provided for comparison. The fund’s total returns include operating expenses (such as transaction costs and management fees) that reduce returns, while the total returns of the index do not.

4

Fund Characteristics

APRIL 30, 2011
Top Ten Holdings	% of net assets
Whole Foods Market, Inc.	2.5%
Netflix, Inc.	2.4%
SXC Health Solutions Corp.	2.1%
priceline.com, Inc.	2.1%
BE Aerospace, Inc.	2.1%
National Oilwell Varco, Inc.	1.7%
Albemarle Corp.	1.5%
Cognizant Technology Solutions Corp., Class A	1.5%
TransDigm Group, Inc.	1.5%
Concho Resources, Inc.	1.5%
Top Five Industries	% of net assets
Machinery	7.8%
Semiconductors & Semiconductor Equipment	6.1%
Software	5.0%
Energy Equipment & Services	4.7%
Internet & Catalog Retail	4.5%
Types of Investments in Portfolio	% of net assets
Domestic Common Stocks	88.8%
Foreign Common Stocks*	10.5%
Total Common Stocks	99.3%
Temporary Cash Investments	0.8%
Other Assets and Liabilities	(0.1)%
*Includes depositary shares, dual listed securities and foreign ordinary shares.

5

Shareholder Fee Example (Unaudited)

Fund shareholders may incur two types of costs: (1) transaction costs, including sales charges (loads) on purchase payments and redemption/exchange fees; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in your fund and to compare these costs with the ongoing cost of investing in other mutual funds.

The example is based on an investment of $1,000 made at the beginning of the period and held for the entire period from November 1, 2010 to April 30, 2011.

Actual Expenses

The table provides information about actual account values and actual expenses for each class. You may use the information, together with the amount you invested, to estimate the expenses that you paid over the period. First, identify the share class you own. Then simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number under the heading “Expenses Paid During Period” to estimate the expenses you paid on your account during this period.

If you hold Investor Class shares of any American Century Investments fund, or Institutional Class shares of the American Century Diversified Bond Fund, in an American Century Investments account (i.e., not a financial intermediary or retirement plan account), American Century Investments may charge you a $12.50 semiannual account maintenance fee if the value of those shares is less than $10,000. We will redeem shares automatically in one of your accounts to pay the $12.50 fee. In determining your total eligible investment amount, we will include your investments in all personal accounts (including American Century Investments Brokerage accounts) registered under your Social Security number. Personal accounts include individual accounts, joint accounts, UGMA/UTMA accounts, personal trusts, Coverdell Education Savings Accounts and IRAs (including traditional, Roth, Rollover, SEP-, SARSEP- and SIMPLE-IRAs), and certain other retirement accounts. If you have only business, business retirement, employer-sponsored or American Century Investments Brokerage accounts, you are currently not subject to this fee. We will not charge the fee as long as you choose to manage your accounts exclusively online. If you are subject to the Account Maintenance Fee, your account value could be reduced by the fee amount.

Hypothetical Example for Comparison Purposes

The table also provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio of each class of your fund and an assumed rate of return of 5% per year before expenses, which is not the actual return of a fund’s share class. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in your fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

6

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads) or redemption/exchange fees. Therefore, the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. In addition, if these transactional costs were included, your costs would have been higher.

	Beginning Account Value 11/1/10	Ending Account Value 4/30/11	Expenses Paid During Period* 11/1/10 – 4/30/11	Annualized Expense Ratio*
Actual
Investor Class	$1,000	$1,200.00	$5.51	1.01%
Institutional Class	$1,000	$1,201.70	$4.42	0.81%
A Class	$1,000	$1,198.50	$6.87	1.26%
C Class	$1,000	$1,194.10	$10.93	2.01%
R Class	$1,000	$1,197.40	$8.23	1.51%
Hypothetical
Investor Class	$1,000	$1,019.79	$5.06	1.01%
Institutional Class	$1,000	$1,020.78	$4.06	0.81%
A Class	$1,000	$1,018.55	$6.31	1.26%
C Class	$1,000	$1,014.83	$10.04	2.01%
R Class	$1,000	$1,017.31	$7.55	1.51%

*Expenses are equal to the class’s annualized expense ratio listed in the table above, multiplied by the average account value over the period, multiplied by 181, the number of days in the most recent fiscal half-year, divided by 365, to reflect the one-half year period.

7

Schedule of Investments

APRIL 30, 2011 (UNAUDITED)

	Shares		Value
Common Stocks — 99.3%
AEROSPACE & DEFENSE — 3.6%
BE Aerospace, Inc.(1)		1,099,000	$	42,410,410
TransDigm Group, Inc.(1)		363,000		30,237,900
				72,648,310
AIR FREIGHT & LOGISTICS — 0.5%
C.H. Robinson Worldwide, Inc.		127,000		10,182,860
AIRLINES — 0.5%
Alaska Air Group, Inc.(1)		161,000		10,605,070
AUTO COMPONENTS — 1.3%
BorgWarner, Inc.(1)		352,000		27,188,480
AUTOMOBILES — 0.5%
Harley-Davidson, Inc.		242,000		9,016,920
BIOTECHNOLOGY — 2.7%
Alexion Pharmaceuticals, Inc.(1)		289,000		28,001,210
United Therapeutics Corp.(1)		151,000		10,110,960
Vertex Pharmaceuticals, Inc.(1)		309,000		17,001,180
				55,113,350
CAPITAL MARKETS — 3.3%
Affiliated Managers Group, Inc.(1)		116,000		12,653,280
American Capital Ltd.(1)		889,000		9,130,030
KKR & Co. LP		633,000		12,001,680
Lazard Ltd., Class A		473,000		19,393,000
Raymond James Financial, Inc.		341,000		12,787,500
				65,965,490
CHEMICALS — 3.0%
Albemarle Corp.		441,000		31,112,550
CF Industries Holdings, Inc.		124,000		17,552,200
International Flavors & Fragrances, Inc.		177,000		11,243,040
				59,907,790
COMMERCIAL SERVICES & SUPPLIES — 1.1%
Stericycle, Inc.(1)		250,000		22,820,000
COMMUNICATIONS EQUIPMENT — 1.2%
Aruba Networks, Inc.(1)		336,000		12,072,480
F5 Networks, Inc.(1)		116,000		11,757,760
				23,830,240
CONSTRUCTION & ENGINEERING — 1.1%
Foster Wheeler AG(1)		295,000		10,493,150
KBR, Inc.		308,000		11,817,960
				22,311,110
CONSUMER FINANCE — 1.1%
Discover Financial Services		906,000		22,505,040
CONTAINERS & PACKAGING — 1.1%
Crown Holdings, Inc.(1)		603,000		22,552,200
ELECTRICAL EQUIPMENT — 2.8%
Cooper Industries plc		325,000		21,433,750
Polypore International, Inc.(1)		179,000		11,056,830
Rockwell Automation, Inc.		282,000		24,570,660
				57,061,240
ELECTRONIC EQUIPMENT, INSTRUMENTS & COMPONENTS — 1.5%
Jabil Circuit, Inc.		592,000		11,745,280
Trimble Navigation Ltd.(1)		389,000		18,220,760
				29,966,040
ENERGY EQUIPMENT & SERVICES — 4.7%
Atwood Oceanics, Inc.(1)		248,000		11,142,640
Core Laboratories NV		107,000		10,269,860
Dril-Quip, Inc.(1)		132,000		10,105,920
FMC Technologies, Inc.(1)		316,000		14,687,680
McDermott International, Inc.(1)		646,000		14,916,140
National Oilwell Varco, Inc.		450,000		34,510,500
				95,632,740
FOOD & STAPLES RETAILING — 2.5%
Whole Foods Market, Inc.		808,000		50,710,080
FOOD PRODUCTS — 1.4%
J.M. Smucker Co. (The)		138,000		10,359,660
Mead Johnson Nutrition Co.		252,000		16,853,760
				27,213,420
HEALTH CARE EQUIPMENT & SUPPLIES — 3.7%
C.R. Bard, Inc.		235,000		25,086,250
Hologic, Inc.(1)		453,000		9,975,060
Mettler-Toledo International, Inc.(1)		117,000		21,925,800
Varian Medical Systems, Inc.(1)		250,000		17,550,000
				74,537,110
HEALTH CARE PROVIDERS & SERVICES — 0.8%
Express Scripts, Inc.(1)		281,000		15,943,940
HEALTH CARE TECHNOLOGY — 2.1%
SXC Health Solutions Corp.(1)		778,000		42,914,480
HOTELS, RESTAURANTS & LEISURE — 3.8%
Chipotle Mexican Grill, Inc.(1)		81,000		21,609,990
Panera Bread Co., Class A(1)		155,000		18,772,050
Royal Caribbean Cruises Ltd.(1)		425,000		16,923,500
Starwood Hotels & Resorts Worldwide, Inc.		330,000		19,658,100
				76,963,640

8

	Shares		Value
HOUSEHOLD PRODUCTS — 1.0%
Church & Dwight Co., Inc.	256,000	$	21,114,880
INTERNET & CATALOG RETAIL — 4.5%
Netflix, Inc.(1)	207,000		48,162,690
priceline.com, Inc.(1)	78,000		42,666,780
			90,829,470
INTERNET SOFTWARE & SERVICES — 3.2%
Baidu, Inc. ADR(1)	131,000		19,456,120
MercadoLibre, Inc.	109,000		9,962,600
VeriSign, Inc.	710,000		26,241,600
WebMD Health Corp.(1)	161,000		9,317,070
			64,977,390
IT SERVICES — 2.7%
Alliance Data Systems Corp.(1)	110,000		10,450,000
Cognizant Technology Solutions Corp., Class A(1)	368,000		30,507,200
VeriFone Systems, Inc.(1)	258,000		14,143,560
			55,100,760
LEISURE EQUIPMENT & PRODUCTS — 0.4%
Brunswick Corp.	336,000		7,852,320
LIFE SCIENCES TOOLS & SERVICES — 2.2%
Illumina, Inc.(1)	328,000		23,281,440
Waters Corp.(1)	206,000		20,188,000
			43,469,440
MACHINERY — 7.8%
AGCO Corp.(1)	472,000		27,177,760
Cummins, Inc.	204,000		24,516,720
Harsco Corp.	274,000		9,754,400
Joy Global, Inc.	235,000		23,723,250
Manitowoc Co., Inc. (The)	208,167		4,619,226
Terex Corp.(1)	279,644		9,726,018
Timken Co.	207,000		11,672,730
Titan International, Inc.	481,000		14,858,090
Trinity Industries, Inc.	288,000		10,425,600
WABCO Holdings, Inc.(1)	279,000		20,604,150
			157,077,944
MEDIA — 2.0%
CBS Corp., Class B	813,000		20,503,860
Imax Corp.(1)	589,884		20,693,131
			41,196,991
METALS & MINING — 2.1%
Cliffs Natural Resources, Inc.	272,000		25,491,840
Walter Energy, Inc.	127,000		17,553,940
			43,045,780
MULTILINE RETAIL — 1.0%
Dollar Tree, Inc.(1)	337,000		19,377,500
OIL, GAS & CONSUMABLE FUELS — 3.7%
Brigham Exploration Co.(1)	532,000		17,837,960
Concho Resources, Inc.(1)	280,000		29,918,000
SandRidge Energy, Inc.(1)	1,140,000		14,090,400
Whiting Petroleum Corp.(1)	176,000		12,232,000
			74,078,360
PHARMACEUTICALS — 0.6%
Shire plc	390,000		12,077,787
PROFESSIONAL SERVICES — 0.5%
Manpower, Inc.	149,000		9,871,250
REAL ESTATE MANAGEMENT & DEVELOPMENT — 2.2%
CB Richard Ellis Group, Inc., Class A(1)	905,000		24,172,550
Jones Lang LaSalle, Inc.	206,000		21,090,280
			45,262,830
ROAD & RAIL — 0.8%
Kansas City Southern(1)	280,000		16,270,800
SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT — 6.1%
Altera Corp.	318,000		15,486,600
ARM Holdings plc	2,615,000		27,289,993
Atmel Corp.(1)	749,000		11,459,700
Cavium Networks, Inc.(1)	441,000		20,824,020
Cypress Semiconductor Corp.(1)	471,000		10,248,960
NXP Semiconductor NV(1)	276,000		9,218,400
Skyworks Solutions, Inc.(1)	564,000		17,743,440
Veeco Instruments, Inc.(1)	203,000		10,379,390
			122,650,503
SOFTWARE — 5.0%
Ariba, Inc.(1)	321,000		11,161,170
Autodesk, Inc.(1)	234,000		10,525,320
Check Point Software Technologies Ltd.(1)	231,000		12,688,830
Citrix Systems, Inc.(1)	322,000		27,157,480
Intuit, Inc.(1)	175,000		9,723,000
salesforce.com, inc.(1)	211,000		29,244,600
			100,500,400
SPECIALTY RETAIL — 3.7%
O’Reilly Automotive, Inc.(1)	354,000		20,907,240
PetSmart, Inc.	633,000		26,693,610
Williams-Sonoma, Inc.	625,000		27,131,250
			74,732,100
TEXTILES, APPAREL & LUXURY GOODS — 1.9%
Fossil, Inc.(1)	224,000		21,454,720
Lululemon Athletica, Inc.(1)	168,000		16,805,040
			38,259,760

9

Shares Value

TRADING COMPANIES & DISTRIBUTORS — 1.7%
Fastenal Co.	311,000	$	20,864,990
WESCO International, Inc.(1)	230,000		14,248,500
			35,113,490
WIRELESS TELECOMMUNICATION SERVICES — 1.9%
NII Holdings, Inc.(1)	249,000		10,353,420
SBA Communications Corp., Class A(1)	709,000		27,388,670
			37,742,090
TOTAL COMMON STOCKS (Cost $1,406,256,675)			2,006,191,395
Temporary Cash Investments — 0.8%
JPMorgan U.S. Treasury Plus Money Market Fund Agency Shares	58,816		58,816
Repurchase Agreement, Bank of America Securities, LLC, (collateralized by various U.S. Treasury obligations, 4.375%, 11/15/39, valued at $17,386,154), in a joint trading account at 0.02%, dated 4/29/11, due 5/2/11 (Delivery value $17,100,029)			17,100,000
TOTAL TEMPORARY CASH INVESTMENTS (Cost $17,158,816)			17,158,816
TOTAL INVESTMENT SECURITIES — 100.1% (Cost $1,423,415,491)			2,023,350,211
OTHER ASSETS AND LIABILITIES — (0.1)%			(2,272,375	)
TOTAL NET ASSETS — 100.0%		$	2,021,077,836

Forward Foreign Currency Exchange Contracts
Contracts to Sell		Counterparty	Settlement Date	Value	Unrealized Gain (Loss)
15,095,210	GBP for USD	Bank of America	5/31/11	$25,205,830	$(348,548)
(Value on Settlement Date $24,857,282)

Geographic Diversification
(as a % of net assets)
United States	88.8%
Canada	4.0%
United Kingdom	1.3%
Netherlands	1.0%
People’s Republic of China	1.0%
Bermuda	1.0%
Israel	0.6%
Ireland	0.6%
Switzerland	0.5%
Argentina	0.5%
Cash and Equivalents*	0.7%

*Includes temporary cash investments and other assets and liabilities.

Notes to Schedule of Investments

ADR = American Depositary Receipt

GBP = British Pound

USD = United States Dollar

(1) Non-income producing.

See Notes to Financial Statements.

10

Statement of Assets and Liabilities

APRIL 30, 2011 (UNAUDITED)
Assets
Investment securities, at value (cost of $1,423,415,491)	$	2,023,350,211
Foreign currency holdings, at value (cost of $49,164)		49,687
Receivable for investments sold		45,926,917
Receivable for capital shares sold		334,974
Dividends and interest receivable		666,882
		2,070,328,671
Liabilities
Payable for investments purchased		36,922,399
Payable for capital shares redeemed		10,182,036
Unrealized loss on forward foreign currency exchange contracts		348,548
Accrued management fees		1,751,946
Distribution and service fees payable		45,906
		49,250,835
Net Assets	$	2,021,077,836
Net Assets Consist of:
Capital (par value and paid-in surplus)	$	1,675,988,927
Accumulated net investment loss		(4,500,005	)
Accumulated net realized loss		(250,055,604	)
Net unrealized appreciation		599,644,518
	$	2,021,077,836

	Net assets	Shares outstanding	Net asset value per share
Investor Class, $0.01 Par Value	$1,709,234,072	93,398,235	$18.30
Institutional Class, $0.01 Par Value	$114,340,220	6,071,044	$18.83
A Class, $0.01 Par Value	$171,272,394	9,680,085	$17.69*
C Class, $0.01 Par Value	$73,782	4,077	$18.10
R Class, $0.01 Par Value	$26,157,368	1,472,040	$17.77
*Maximum offering price $18.77 (net asset value divided by 0.9425).

See Notes to Financial Statements.

11

Statement of Operations

FOR THE SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED)
Investment Income (Loss)
Income:
Dividends (net of foreign taxes withheld of $11,250)	$	6,413,101
Interest		14,764
		6,427,865
Expenses:
Management fees		10,923,686
Distribution and service fees:
A Class		226,229
C Class		231
R Class		64,339
Directors’ fees and expenses		60,235
		11,274,720
Net investment income (loss)		(4,846,855	)
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment transactions		273,341,845
Futures contract transactions		306,293
Foreign currency transactions		(1,330,161	)
		272,317,977
Change in net unrealized appreciation (depreciation) on:
Investments		130,601,037
Translation of assets and liabilities in foreign currencies		47,241
		130,648,278
Net realized and unrealized gain (loss)		402,966,255
Net Increase (Decrease) in Net Assets Resulting from Operations	$	398,119,400

See Notes to Financial Statements.

12

Statement of Changes in Net Assets

SIX MONTHS ENDED APRIL 30, 2011 (UNAUDITED) AND YEAR ENDED OCTOBER 31, 2010
Increase (Decrease) in Net Assets	2011			2010
Operations
Net investment income (loss)	$	(4,846,855	)	$	(9,950,529	)
Net realized gain (loss)		272,317,977			354,965,987
Change in net unrealized appreciation (depreciation)		130,648,278			156,009,051
Net increase (decrease) in net assets resulting from operations		398,119,400			501,024,509
Capital Share Transactions
Net increase (decrease) in net assets from capital share transactions		(504,717,277	)		(553,319,017	)
Net increase (decrease) in net assets		(106,597,877	)		(52,294,508	)
Net Assets
Beginning of period		2,127,675,713			2,179,970,221
End of period	$	2,021,077,836		$	2,127,675,713
Accumulated undistributed net investment income (loss)	$	(4,500,005	)	$	346,850

See Notes to Financial Statements.

13

Notes to Financial Statements

APRIL 30, 2011 (UNAUDITED)

1. Organization

American Century Mutual Funds, Inc. (the corporation) is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company and is organized as a Maryland corporation. Vista Fund (the fund) is one fund in a series issued by the corporation. The fund is diversified as defined under the 1940 Act. The fund’s investment objective is to seek long-term capital growth. The fund pursues its objective by investing primarily in equity securities of companies that are medium-sized and smaller at the time of purchase that management believes will increase in value.

The fund is authorized to issue the Investor Class, the Institutional Class, the A Class (formerly Advisor Class), the C Class and the R Class. The A Class may incur an initial sales charge. The A Class and C Class may be subject to a contingent deferred sales charge. The share classes differ principally in their respective sales charges and distribution and shareholder servicing expenses and arrangements. The Institutional Class is made available to institutional shareholders or through financial intermediaries whose clients do not require the same level of shareholder and administrative services as shareholders of other classes. As a result, the Institutional Class is charged a lower unified management fee. Sale of the C Class commenced on March 1, 2010.

2. Significant Accounting Policies

The following is a summary of significant accounting policies consistently followed by the fund in preparation of its financial statements. The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America, which may require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from these estimates.

Investment Valuations — The fund determines the fair value of its investments and computes its net asset value per share as of the close of regular trading (usually 4 p.m. Eastern time) on the New York Stock Exchange (NYSE) on each day the NYSE is open.

Equity securities that are listed or traded on a domestic securities exchange are valued at the last reported sales price or at the official closing price as provided by the exchange. Equity securities traded on foreign securities exchanges are typically valued at the closing price on the exchange where primarily traded or as of the close of the NYSE, if that is earlier. If no last sales price is reported, or if local convention or regulation so provides, the mean of the latest bid and asked prices is used. Depending on local convention or regulation, securities traded over-the-counter are valued at the mean of the latest bid and asked prices, the last sales price, or the official closing price. In its determination of fair value, the fund may review several factors including: market information specific to a security; news developments in U.S. and foreign markets; the performance of particular U.S. and foreign securities, indices, comparable securities, American Depositary Receipts, Exchange-Traded Funds, and other relevant market indicators.

Debt securities maturing within 60 days at the time of purchase may be valued at cost, plus or minus any amortized discount or premium or at the evaluated mean as provided by an independent pricing service. Evaluated mean prices are commonly derived through utilization of market models, which may consider, among other factors, trade data, quotations from dealers and active market makers, relevant yield curve and spread data, related sector levels, creditworthiness, and other relevant market information on the same or comparable securities.

Investments in open-end management investment companies are valued at the reported net asset value per share. Repurchase agreements are valued at cost. Exchange-traded futures contracts are valued at the settlement price as provided by the appropriate clearing corporation. Forward foreign currency exchange contracts are valued at the mean of the latest bid and asked prices of the forward currency rates as provided by an independent pricing service.

14

The value of investments initially expressed in foreign currencies is translated into U.S. dollars at prevailing exchange rates.

If the fund determines that the market price for a portfolio security is not readily available or the valuation methods mentioned above do not reflect a security’s fair value, such security is valued as determined in good faith by the Board of Directors or its designee, in accordance with procedures adopted by the Board of Directors. Circumstances that may cause the fund to use these procedures to value a security include, but are not limited to: a security has been declared in default; trading in a security has been halted during the trading day; there is a foreign market holiday and no trading occurred; or an event occurred between the close of a foreign exchange and the NYSE that may affect the value of a security.

Security Transactions — Security transactions are accounted for as of the trade date. Net realized gains and losses are determined on the identified cost basis, which is also used for federal income tax purposes.

Investment Income — Dividend income less foreign taxes withheld, if any, is recorded as of the ex-dividend date. Interest income is recorded on the accrual basis and includes accretion of discounts and amortization of premiums.

Foreign Currency Translations — All assets and liabilities initially expressed in foreign currencies are translated into U.S. dollars at prevailing exchange rates at period end. The fund may enter into spot foreign currency exchange contracts to facilitate transactions denominated in a foreign currency. Purchases and sales of investment securities, dividend and interest income, spot foreign currency exchange contracts, and expenses are translated at the rates of exchange prevailing on the respective dates of such transactions. Net realized and unrealized foreign currency exchange gains or losses related to investment securities are a component of net realized gain (loss) on investment transactions and change in net unrealized appreciation (depreciation) on investments, respectively.

Repurchase Agreements — The fund may enter into repurchase agreements with institutions that American Century Investment Management, Inc. (ACIM) (the investment advisor) has determined are creditworthy pursuant to criteria adopted by the Board of Directors. The fund requires that the collateral, represented by securities, received in a repurchase transaction be transferred to the custodian in a manner sufficient to enable the fund to obtain those securities in the event of a default under the repurchase agreement. ACIM monitors, on a daily basis, the securities transferred to ensure the value, including accrued interest, of the securities under each repurchase agreement is equal to or greater than amounts owed to the fund under each repurchase agreement.

Joint Trading Account — Pursuant to an Exemptive Order issued by the Securities and Exchange Commission, the fund, along with certain other funds in the American Century Investments family of funds, may transfer uninvested cash balances into a joint trading account. These balances are invested in one or more repurchase agreements that are collateralized by U.S. Treasury or Agency obligations.

Income Tax Status — It is the fund’s policy to distribute substantially all net investment income and net realized gains to shareholders and to otherwise qualify as a regulated investment company under provisions of the Internal Revenue Code. The fund is no longer subject to examination by tax authorities for years prior to 2007. At this time, management believes there are no uncertain tax positions which, based on their technical merit, would not be sustained upon examination and for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Accordingly, no provision has been made for federal or state income taxes.

Multiple Class — All shares of the fund represent an equal pro rata interest in the net assets of the class to which such shares belong, and have identical voting, dividend, liquidation and other rights and the same terms and conditions, except for class specific expenses and exclusive rights to vote on matters affecting only individual classes. Income, non-class specific expenses, and realized and unrealized capital gains and losses of the fund are allocated to each class of shares based on their relative net assets.

15

Distributions to Shareholders — Distributions from net investment income and net realized gains, if any, are generally declared and paid annually.

Indemnifications — Under the corporation’s organizational documents, its officers and directors are indemnified against certain liabilities arising out of the performance of their duties to the fund. In addition, in the normal course of business, the fund enters into contracts that provide general indemnifications. The maximum exposure under these arrangements is unknown as this would involve future claims that may be made against a fund. The risk of material loss from such claims is considered by management to be remote.

3. Fees and Transactions with Related Parties

Management Fees — The corporation has entered into a management agreement with ACIM, under which ACIM provides the fund with investment advisory and management services in exchange for a single, unified management fee (the fee) per class. The agreement provides that all expenses of managing and operating the fund, except distribution and service fees, brokerage expenses, taxes, interest, fees and expenses of the independent directors (including legal counsel fees), and extraordinary expenses, will be paid by ACIM. The fee is computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The annual management fee is 1.000% for the Investor Class, A Class, C Class and R Class and 0.800% for the Institutional Class.

Distribution and Service Fees — The Board of Directors has adopted a separate Master Distribution and Individual Shareholder Services Plan for each of the A Class, C Class and R Class (collectively the plans), pursuant to Rule 12b-1 of the 1940 Act. The plans provide that the A Class will pay American Century Investment Services, Inc. (ACIS) an annual distribution and service fee of 0.25%. The plans provide that the C Class will pay ACIS an annual distribution and service fee of 1.00%, of which 0.25% is paid for individual shareholder services and 0.75% is paid for distribution services. The plans provide that the R Class will pay ACIS an annual distribution and service fee of 0.50%. The fees are computed and accrued daily based on each class’s daily net assets and paid monthly in arrears. The fees are used to pay financial intermediaries for distribution and individual shareholder services. Fees incurred under the plans during the six months ended April 30, 2011 are detailed in the Statement of Operations.

Related Parties — Certain officers and directors of the corporation are also officers and/or directors of American Century Companies, Inc. (ACC), the parent of the corporation’s investment advisor, ACIM, the distributor of the corporation, ACIS, and the corporation’s transfer agent, American Century Services, LLC. Various funds in a series issued by American Century Asset Allocation Portfolios, Inc. (ACAAP) own, in aggregate, 10% of the shares of the fund. ACAAP does not invest in the fund for the purpose of exercising management or control.

The fund is eligible to invest in a money market fund for temporary purposes, which is managed by J.P. Morgan Investment Management, Inc. (JPMIM). The fund has a mutual funds services agreement with J.P. Morgan Investor Services Co. (JPMIS). JPMorgan Chase Bank (JPMCB) is a custodian of the fund. JPMIM, JPMIS and JPMCB are wholly owned subsidiaries of JPMorgan Chase & Co. (JPM). JPM is an equity investor in ACC.

4. Investment Transactions

Purchases and sales of investment securities, excluding short-term investments, for the six months ended April 30, 2011 were $865,652,510 and $1,363,627,492, respectively.

16

5. Capital Share Transactions

Transactions in shares of the fund were as follows:

	Six months ended April 30, 2011						Year ended October 31, 2010(1)
	Shares			Amount			Shares			Amount
Investor Class/Shares Authorized		750,000,000						750,000,000
Sold		5,054,026		$	85,508,422			8,630,658		$	117,497,322
Redeemed		(27,170,927	)		(472,830,482	)		(32,468,753	)		(444,901,904	)
		(22,116,901	)		(387,322,060	)		(23,838,095	)		(327,404,582	)
Institutional Class/Shares Authorized		80,000,000						80,000,000
Sold		1,269,375			21,828,283			4,712,353			65,500,385
Redeemed		(4,966,452	)		(85,814,529	)		(11,923,548	)		(169,469,691	)
		(3,697,077	)		(63,986,246	)		(7,211,195	)		(103,969,306	)
A Class/Shares Authorized		310,000,000						310,000,000
Sold		1,394,054			22,780,252			2,682,180			35,631,591
Redeemed		(4,351,908	)		(71,060,058	)		(11,741,693	)		(156,158,675	)
		(2,957,854	)		(48,279,806	)		(9,059,513	)		(120,527,084	)
C Class/Shares Authorized		50,000,000						50,000,000
Sold		2,088			35,410			1,989			27,200
R Class/Shares Authorized		10,000,000						10,000,000
Sold		169,692			2,807,140			506,557			6,818,706
Redeemed		(495,752	)		(7,971,715	)		(614,404	)		(8,263,951	)
		(326,060	)		(5,164,575	)		(107,847	)		(1,445,245	)
Net increase (decrease)		(29,095,804	)	$	(504,717,277	)		(40,214,661	)	$	(553,319,017	)

(1) March 1, 2010 (commencement of sale) through October 31, 2010 for the C Class.

6. Fair Value Measurements

The fund’s securities valuation process is based on several considerations and may use multiple inputs to determine the fair value of the positions held by the fund. In conformity with accounting principles generally accepted in the United States of America, the inputs used to determine a valuation are classified into three broad levels as follows:

• Level 1 valuation inputs consist of unadjusted quoted prices in an active market for identical securities;

• Level 2 valuation inputs consist of direct or indirect observable market data (including quoted prices for similar securities, evaluations of subsequent market events, interest rates, prepayment speeds, credit risk, etc.); or

• Level 3 valuation inputs consist of unobservable data (including a fund’s own assumptions).

The level classification is based on the lowest level input that is significant to the fair valuation measurement. The valuation inputs are not necessarily an indication of the risks associated with investing in these securities or other financial instruments.

17

The following is a summary of the level classifications as of period end. The Schedule of Investments provides additional information on the fund’s portfolio holdings.

	Level 1		Level 2			Level 3
Investment Securities
Domestic Common Stocks	$	1,794,929,004		—			—
Foreign Common Stocks		171,894,611	$	39,367,780			—
Temporary Cash Investments		58,816		17,100,000			—
Total Value of Investment Securities	$	1,966,882,431	$	56,467,780			—
Other Financial Instruments
Total Unrealized Gain (Loss) on Forward Foreign Currency Exchange Contracts		—	$	(348,548	)		—

7. Derivative Instruments

Equity Price Risk — The fund is subject to equity price risk in the normal course of pursuing its investment objectives. A fund may enter into futures contracts based on an equity index in order to manage its exposure to changes in market conditions. A fund may purchase futures contracts to gain exposure to increases in market value or sell futures contracts to protect against a decline in market value. Upon entering into a futures contract, a fund is required to deposit either cash or securities in an amount equal to a certain percentage of the contract value (initial margin). Subsequent payments (variation margin) are made or received daily, in cash, by a fund. The variation margin is equal to the daily change in the contract value and is recorded as unrealized gains and losses. A fund recognizes a realized gain or loss when the contract is closed or expires. Net realized and unrealized gains or losses occurring during the holding period of futures contracts are a component of net realized gain (loss) on futures contract transactions and change in net unrealized appreciation (depreciation) on futures contracts, respectively. One of the risks of entering into futures contracts is the possibility that the change in value of the contract may not correlate with the changes in value of the underlying securities. During the period, the fund infrequently purchased equity price risk derivative instruments for temporary investment purposes.

Foreign Currency Risk — The fund is subject to foreign currency exchange rate risk in the normal course of pursuing its investment objectives. The value of foreign investments held by a fund may be significantly affected by changes in foreign currency exchange rates. The dollar value of a foreign security generally decreases when the value of the dollar rises against the foreign currency in which the security is denominated and tends to increase when the value of the dollar declines against such foreign currency. A fund may enter into forward foreign currency exchange contracts to reduce a fund’s exposure to foreign currency exchange rate fluctuations. The net U.S. dollar value of foreign currency underlying all contractual commitments held by a fund and the resulting unrealized appreciation or depreciation are determined daily. Realized gain or loss is recorded upon the termination of the contract. Net realized and unrealized gains or losses occurring during the holding period of forward foreign currency exchange contracts are a component of net realized gain (loss) on foreign currency transactions and change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies, respectively. A fund bears the risk of an unfavorable change in the foreign currency exchange rate underlying the forward contract. Additionally, losses, up to the fair value, may arise if the counterparties do not perform under the contract terms. The risk of loss from non-performance by the counterparty may be reduced by the use of master netting agreements. The foreign currency risk derivative instruments held at period end as disclosed on the Schedule of Investments are indicative of the fund’s typical volume during the period.

18

Value of Derivative Instruments as of April 30, 2011
	Asset Derivatives				Liability Derivatives
Type of Risk Exposure	Location on Statement of Assets and Liabilities	Value			Location on Statement of Assets and Liabilities	Value
Foreign Currency Risk	Unrealized gain on forward foreign currency exchange contracts		—		Unrealized loss on forward foreign currency exchange contracts	$	348,548
Effect of Derivative Instruments on the Statement of Operations for the Six Months Ended April 30, 2011
	Net Realized Gain (Loss)				Change in Net Unrealized Appreciation (Depreciation)
Type of Risk Exposure	Location on Statement of Operations	Value			Location on Statement of Operations	Value
Equity Price Risk	Net realized gain (loss) on futures contract transactions	$	306,293		Change in net unrealized appreciation (depreciation) on futures contracts		—
Foreign Currency Risk	Net realized gain (loss) on foreign currency transactions		(1,313,488	)	Change in net unrealized appreciation (depreciation) on translation of assets and liabilities in foreign currencies	$	16,718
		$	(1,007,195	)		$	16,718

8. Risk Factors

There are certain risks involved in investing in foreign securities. These risks include those resulting from future adverse political, social, and economic developments, fluctuations in currency exchange rates, the possible imposition of exchange controls, and other foreign laws or restrictions.

The fund invests in common stocks of small companies. Because of this, it may be subject to greater risk and market fluctuations than a fund investing in larger, more established companies.

9. Federal Tax Information

The book-basis character of distributions made during the year from net investment income or net realized gains may differ from their ultimate characterization for federal income tax purposes. These differences reflect the differing character of certain income items and net realized gains and losses for financial statement and tax purposes, and may result in reclassification among certain capital accounts on the financial statements.

As of April 30, 2011, the components of investments for federal income tax purposes were as follows:

Federal tax cost of investments	$	1,427,689,533
Gross tax appreciation of investments	$	599,589,003
Gross tax depreciation of investments		(3,928,325	)
Net tax appreciation (depreciation) of investments	$	595,660,678

The difference between book-basis and tax-basis cost and unrealized appreciation (depreciation) is attributable primarily to the tax deferral of losses on wash sales.

19

As of October 31, 2010, the fund had accumulated capital losses of $(519,773,871), which represent net capital loss carryovers that may be used to offset future realized capital gains for federal income tax purposes. Future capital loss carryover utilization in any given year may be subject to Internal Revenue Code limitations. Capital loss carryovers expire in 2017.

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Act”) was enacted, which changed various technical rules governing the tax treatment of regulated investment companies. The changes are generally effective for taxable years beginning after the date of enactment. Under the Act, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after the date of enactment for an unlimited period. However, any losses incurred during those future taxable years will be required to be utilized prior to the losses incurred in pre-enactment taxable years, which carry an expiration date. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused.

20

Financial Highlights

Investor Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	15.25		$	12.13		$	12.43		$	24.24		$	16.35		$	14.99
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.04	)		(0.06	)		(0.05	)		(0.11	)		(0.12	)		(0.04	)
Net Realized and    Unrealized Gain (Loss)		3.09			3.18			(0.25	)		(9.61	)		8.14			1.40
Total From    Investment Operations		3.05			3.12			(0.30	)		(9.72	)		8.02			1.36
Distributions
From Net    Realized Gains		—			—			—			(2.09	)		(0.13	)		—
Net Asset Value, End of Period	$	18.30		$	15.25		$	12.13		$	12.43		$	24.24		$	16.35
Total Return(3)		20.00	%		25.72	%		(2.41	)%		(43.58	)%		49.39	%		9.07	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.01	%(4)		1.01	%		1.00	%		1.00	%		1.00	%		1.00	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.43	)%(4)		(0.45	)%		(0.48	)%		(0.56	)%		(0.60	)%		(0.23	)%
Portfolio Turnover Rate		40	%		132	%		183	%		167	%		121	%		234	%
Net Assets, End of Period (in millions)	$	1,709		$	1,761		$	1,691		$	1,801		$	2,921		$	1,965

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

21

Institutional Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	15.67		$	12.45		$	12.73		$	24.72		$	16.64		$	15.22
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.02	)		(0.03	)		(0.03	)		(0.07	)		(0.08	)		(0.01	)
Net Realized and    Unrealized Gain (Loss)		3.18			3.25			(0.25	)		(9.83	)		8.29			1.43
Total From    Investment Operations		3.16			3.22			(0.28	)		(9.90	)		8.21			1.42
Distributions
From Net    Realized Gains		—			—			—			(2.09	)		(0.13	)		—
Net Asset Value, End of Period	$	18.83		$	15.67		$	12.45		$	12.73		$	24.72		$	16.64
Total Return(3)		20.17	%		25.86	%		(2.12	)%		(43.50	)%		49.68	%		9.33	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		0.81	%(4)		0.81	%		0.80	%		0.80	%		0.80	%		0.80	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.23	)%(4)		(0.25	)%		(0.28	)%		(0.36	)%		(0.40	)%		(0.03	)%
Portfolio Turnover Rate		40	%		132	%		183	%		167	%		121	%		234	%
Net Assets, End of Period (in thousands)	$	114,340		$	153,112		$	211,357		$	238,727		$	254,528		$	132,325

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

22

A Class(1)
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(2)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	14.76		$	11.77		$	12.09		$	23.69		$	16.03		$	14.73
Income From Investment Operations
Net Investment    Income (Loss)(3)		(0.05	)		(0.09	)		(0.08	)		(0.15	)		(0.16	)		(0.08	)
Net Realized and    Unrealized Gain (Loss)		2.98			3.08			(0.24	)		(9.36	)		7.95			1.38
Total From    Investment Operations		2.93			2.99			(0.32	)		(9.51	)		7.79			1.30
Distributions
From Net    Realized Gains		—			—			—			(2.09	)		(0.13	)		—
Net Asset Value, End of Period	$	17.69		$	14.76		$	11.77		$	12.09		$	23.69		$	16.03
Total Return(4)		19.85	%		25.40	%		(2.65	)%		(43.72	)%		48.94	%		8.83	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.26	%(5)		1.26	%		1.25	%		1.25	%		1.25	%		1.25	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.68	)%(5)		(0.70	)%		(0.73	)%		(0.81	)%		(0.85	)%		(0.48	)%
Portfolio Turnover Rate		40	%		132	%		183	%		167	%		121	%		234	%
Net Assets, End of Period (in thousands)	$	171,272		$	186,529		$	255,419		$	257,057		$	380,555		$	210,576

(1) Prior to March 1, 2010, the A Class was referred to as the Advisor Class.

(2) Six months ended April 30, 2011 (unaudited).

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

See Notes to Financial Statements.

23

C Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010(2)
Per-Share Data
Net Asset Value, Beginning of Period	$	15.15		$	13.73
Income From Investment Operations
Net Investment Income (Loss)(3)		(0.13	)		(0.14	)
Net Realized and Unrealized Gain (Loss)		3.08			1.56
Total From Investment Operations		2.95			1.42
Net Asset Value, End of Period	$	18.10		$	15.15
Total Return(4)		19.41	%		10.34	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		2.01	%(5)		2.01	%(5)
Ratio of Net Investment Income (Loss) to Average Net Assets		(1.43	)%(5)		(1.51	)%(5)
Portfolio Turnover Rate		40	%		132	%(6)
Net Assets, End of Period (in thousands)	$	74		$	30

(1) Six months ended April 30, 2011 (unaudited).

(2) March 1, 2010 (commencement of sale) through October 31, 2010.

(3) Computed using average shares outstanding throughout the period.

(4) Total returns are calculated based on the net asset value of the last business day and do not reflect applicable sales charges. Total returns for periods less than one year are not annualized.

(5) Annualized.

(6) Portfolio turnover is calculated at the fund level. Percentage indicated was calculated for the year ended October 31, 2010.

See Notes to Financial Statements.

24

R Class
For a Share Outstanding Throughout the Years Ended October 31 (except as noted)
	2011(1)			2010			2009			2008			2007			2006
Per-Share Data
Net Asset Value, Beginning of Period	$	14.84		$	11.87		$	12.22		$	23.98		$	16.25		$	14.97
Income From Investment Operations
Net Investment    Income (Loss)(2)		(0.08	)		(0.13	)		(0.12	)		(0.18	)		(0.21	)		(0.16	)
Net Realized and    Unrealized Gain (Loss)		3.01			3.10			(0.23	)		(9.49	)		8.07			1.44
Total From    Investment Operations		2.93			2.97			(0.35	)		(9.67	)		7.86			1.28
Distributions
From Net    Realized Gains		—			—			—			(2.09	)		(0.13	)		—
Net Asset Value, End of Period	$	17.77		$	14.84		$	11.87		$	12.22		$	23.98		$	16.25
Total Return(3)		19.74	%		25.02	%		(2.86	)%		(43.87	)%		48.71	%		8.55	%
Ratios/Supplemental Data
Ratio of Operating Expenses to Average Net Assets		1.51	%(4)		1.51	%		1.50	%		1.50	%		1.50	%		1.50	%
Ratio of Net Investment Income (Loss) to Average Net Assets		(0.93	)%(4)		(0.95	)%		(0.98	)%		(1.06	)%		(1.10	)%		(0.73	)%
Portfolio Turnover Rate		40	%		132	%		183	%		167	%		121	%		234	%
Net Assets, End of Period (in thousands)	$	26,157		$	26,686		$	22,618		$	11,423		$	2,398		$	337

(1) Six months ended April 30, 2011 (unaudited).

(2) Computed using average shares outstanding throughout the period.

(3) Total returns are calculated based on the net asset value of the last business day. Total returns for periods less than one year are not annualized.

(4) Annualized.

See Notes to Financial Statements.

25

Additional Information

Retirement Account Information

As required by law, distributions you receive from certain IRAs, or 403(b), 457 and qualified plans are subject to federal income tax withholding, unless you elect not to have withholding apply. Tax will be withheld on the total amount withdrawn even though you may be receiving amounts that are not subject to withholding, such as nondeductible contributions. In such case, excess amounts of withholding could occur. You may adjust your withholding election so that a greater or lesser amount will be withheld.

If you don’t want us to withhold on this amount, you must notify us to not withhold the federal income tax. You may notify us in writing or in certain situations by telephone or through other electronic means. You have the right to revoke your withholding election at any time and any election you make may remain in effect until revoked by filing a new election.

Remember, even if you elect not to have income tax withheld, you are liable for paying income tax on the taxable portion of your withdrawal. If you elect not to have income tax withheld or you don’t have enough income tax withheld, you may be responsible for payment of estimated tax. You may incur penalties under the estimated tax rules if your withholding and estimated tax payments are not sufficient. You can reduce or defer the income tax on a distribution by directly or indirectly rolling such distribution over to another IRA or eligible plan. You should consult your tax advisor for additional information.

State tax will be withheld if, at the time of your distribution, your address is within one of the mandatory withholding states and you have federal income tax withheld. State taxes will be withheld from your distribution in accordance with the respective state rules.

Proxy Voting Guidelines

American Century Investment Management, Inc., the fund’s investment advisor, is responsible for exercising the voting rights associated with the securities purchased and/or held by the fund. A description of the policies and procedures the advisor uses in fulfilling this responsibility is available without charge, upon request, by calling 1-800-345-2021. It is also available on American Century Investments’ website at americancentury.com and on the Securities and Exchange Commission’s website at sec.gov. Information regarding how the investment advisor voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is available on the “About Us” page at americancentury.com. It is also available at sec.gov.

Quarterly Portfolio Disclosure

The fund files its complete schedule of portfolio holdings with the Securities and Exchange Commission (SEC) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Forms N-Q are available on the SEC’s website at sec.gov, and may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The fund also makes its complete schedule of portfolio holdings for the most recent quarter of its fiscal year available on its website at americancentury.com and, upon request, by calling 1-800-345-2021.

26

Notes

27

Notes

28

Contact Us	americancentury.com
Automated Information Line	1-800-345-8765
Investor Services Representative	1-800-345-2021 or 816-531-5575
Investors Using Advisors	1-800-378-9878
Business, Not-For-Profit, Employer-Sponsored Retirement Plans	1-800-345-3533
Banks and Trust Companies, Broker-Dealers, Financial Professionals, Insurance Companies	1-800-345-6488
Telecommunications Device for the Deaf	1-800-634-4113

American Century Mutual Funds, Inc.

Investment Advisor:

American Century Investment Management, Inc.

Kansas City, Missouri

This report and the statements it contains are submitted for the general information of our shareholders. The report is not authorized for distribution to prospective investors unless preceded or accompanied by an effective prospectus.

©2011 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SAN-71841   1106

ITEM 2.  CODE OF ETHICS.

Not applicable for semiannual report filings.

ITEM 3.  AUDIT COMMITTEE FINANCIAL EXPERT.

Not applicable for semiannual report filings.

ITEM 4.  PRINCIPAL ACCOUNTANT FEES AND SERVICES.

Not applicable for semiannual report filings.

ITEM 5.  AUDIT COMMITTEE OF LISTED REGISTRANTS.

Not applicable.

ITEM 6.  INVESTMENTS.

(a) The schedule of investments is included as part of the report to stockholders filed under Item 1 of this Form.

(b) Not applicable.

ITEM 7.  DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable.

ITEM 8.  PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable.

ITEM 9.  PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT INVESTMENT COMPANY AND AFFILIATED PURCHASERS.

Not applicable.

ITEM 10.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

During the reporting period, there were no material changes to the procedures by which shareholders may recommend nominees to the registrant’s board.

ITEM 11.  CONTROLS AND PROCEDURES.

(a) The registrant's principal executive officer and principal financial officer have concluded that the registrant's disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) are effective based on their evaluation of these controls and procedures as of a date within 90 days of the filing date of this report.

(b) There were no changes in the registrant's internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) that occurred during the registrant's second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant's internal control over financial reporting.

ITEM 12.  EXHIBITS.

(a)(1) Not applicable for semiannual report filings.

(a)(2) Separate certifications by the registrant’s principal executive officer and principal financial officer, pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 and Rule 30a-2(a) under the Investment Company Act of 1940, are filed and attached hereto as EX-99.CERT.

(a)(3) Not applicable.

(b) A certification by the registrant’s chief executive officer and chief financial officer, pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, is furnished and attached hereto as EX- 99.906CERT.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Registrant:	AMERICAN CENTURY MUTUAL FUNDS, INC.
By:	/s/ Jonathan S. Thomas
	Name:	Jonathan S. Thomas
	Title:	President
Date:	June 29, 2011

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By:	/s/ Jonathan S. Thomas
	Name:	Jonathan S. Thomas
	Title:	President
		(principal executive officer)
Date:	June 29, 2011

By:	/s/ Robert J. Leach
	Name:	Robert J. Leach
	Title:	Vice President, Treasurer, and
		Chief Financial Officer
		(principal financial officer)
Date:	June 29, 2011