American Municipal Income Portfolio (XAA) 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 811-07678

American Municipal Income Portfolio Inc.

(Exact name of registrant as specified in charter)

800 Nicollet Mall, Minneapolis, MN	55402
(Address of principal executive offices)	(Zip code)

Jill M. Stevenson, 800 Nicollet Mall, Minneapolis, MN 55402

(Name and address of agent for service)

Registrant’s telephone number, including area code: 800-677-3863

Date of fiscal year end:	August 31
Date of reporting period:	February 29, 2012

Form N-CSR is to be used by management investment companies to file reports with the Commission not later than 10 days after the transmission to stockholders of any report that is required to be transmitted to stockholders under Rule 30e-1 under the Investment Company Act of 1940 (17 CFR 270.30e-1). The Commission may use the information provided on Form N-CSR in its regulatory, disclosure review, inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-CSR, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-CSR unless the Form displays a currently valid Office of Management and Budget (“OMB”) control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. Section 3507.

SEMIANNUAL REPORT

February 29, 2012

XAA American Municipal Income Portfolio

American Municipal Income Portfolio

OUR IMAGE–GEORGE WASHINGTON

His rich legacy as patriot and leader is widely recognized as embodying the sound judgment, reliability, and strategic vision that are central to our brand. Fashioned in a style reminiscent of an 18th century engraving, the illustration conveys the symbolic strength and vitality of Washington, which are attributes that we value at First American.

TABLE OF CONTENTS

1	Explanation of Financial Statements
2	Fund Overview
4	Schedule of Investments
10	Statement of Assets and Liabilities
11	Statement of Operations
12	Statements of Changes in Net Assets
13	Financial Highlights
14	Notes to Financial Statements
22	Notice to Shareholders

NOT FDIC INSURED      NO BANK GUARANTEE      MAY LOSE VALUE

EXPLANATION OF FINANCIAL STATEMENTS

As a shareholder in the fund, you receive shareholder reports semiannually. We strive to present this financial information in an easy-to-understand format; however, for many investors, the information contained in this shareholder report may seem very technical. So, we would like to take this opportunity to explain several sections of the shareholder report.

The Schedule of Investments details all of the securities held in the fund and their related dollar values on the last day of the reporting period. Securities are usually presented by type (bonds, common stock, etc.) and by industry classification (healthcare, education, etc.). This information is useful for analyzing how your fund’s assets are invested and seeing where your portfolio manager believes the best opportunities exist to meet your objectives. Holdings are subject to change without notice and do not constitute a recommendation of any individual security. The Notes to Financial Statements provide additional details on how the securities are valued.

The Statement of Assets and Liabilities lists the assets and liabilities of the fund on the last day of the reporting period and presents the fund’s net asset value (“NAV”) and market price per share. The NAV is calculated by dividing the fund’s net assets (assets minus liabilities) by the number of shares outstanding. The market price is the closing price on the exchange on which the fund’s shares trade. This price, which may be higher or lower than the fund’s NAV, is the price an investor pays or receives when shares of the fund are purchased or sold. The investments, as presented in the Schedule of Investments, comprise substantially all of the fund’s assets. Other assets include cash and receivables for items such as income earned by the fund but not yet received. Liabilities include payables for items such as fund expenses incurred but not yet paid.

The Statement of Operations details the dividends and interest income earned from investments as well as the expenses incurred by the fund during the reporting period. Fund expenses may be reduced through fee waivers or reimbursements. This statement reflects total expenses before any waivers or reimbursements, the amount of waivers and reimbursements (if any), and the net expenses. This statement also shows the net realized and unrealized gains and losses from investments owned during the period. The Notes to Financial Statements provide additional details on investment income and expenses of the fund.

The Statement of Changes in Net Assets describes how the fund’s net assets were affected by its operating results and distributions to shareholders during the reporting period. This statement is important to investors because it shows exactly what caused the fund’s net asset size to change during the period.

The Statement of Cash Flows is required when a fund has a substantial amount of illiquid investments, a substantial amount of the fund’s securities are internally fair valued, or the fund carries some amount of debt. When presented, this statement explains the change in cash during the reporting period. It reconciles net cash provided by and used for operating activities to the net increase or decrease in net assets from operations and classifies cash receipts and payments as resulting from operating, investing, and financing activities.

The Financial Highlights provide a per-share breakdown of the components that affected the fund’s NAV for the current and past reporting periods. It also shows total return, net investment income ratios, expense ratios, and portfolio turnover rates. The net investment income ratios summarize the income earned less expenses, divided by the average net assets. The expense ratios represent the percentage of average net assets that were used to cover operating expenses during the period. The portfolio turnover rate represents the percentage of the fund’s holdings that have changed over the course of the period, and gives an idea of how long the fund holds onto a particular security. A 100% turnover rate implies that an amount equal to the value of the entire portfolio is turned over in a year through the purchase or sale of securities.

The Notes to Financial Statements disclose the organizational background of the fund, its significant accounting policies, federal tax information, fees and compensation paid to affiliates, and significant risks and contingencies.

We hope this guide to your shareholder report will help you get the most out of this important resource.

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 1

Fund Overview

Portfolio Allocation¹

As a percentage of total investments on February 29, 2012

Health Care Revenue	38	%
General Obligations	22
Education Revenue	11
Utility Revenue	8
Tax Revenue	5
Pre-refunded Issues2	4
Housing Revenue	4
Economic Development Revenue	2
Leasing Revenue	2
Transportation Revenue	2
Pollution Control	1
Short-Term Investments	1
	100	%

¹Portfolio allocations are subject to change and are not recommendations to buy or sell any security.

²Within the Schedule of Investments, pre-refunded issues are classified under their applicable industries.

Bond Credit Quality Breakdown³

As a percentage of long-term investments on February 29, 2012

AAA	4	%
AA	37
A	25
BBB	18
BB	1
NR	15
	100	%

³Individual security ratings are based on information from Moody’s Investors Service, Standard & Poor’s, and/or Fitch. If there are multiple ratings for a security, the lowest rating is used unless ratings are provided by all three agencies, in which case the middle rating is used.

2 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

Geographical Distribution

As a percentage of long-term investments on February 29, 2012. Shaded areas without values indicate states in which the fund has invested less than 0.50% of its assets.

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 3

Schedule of Investments             February 29, 2012 (unaudited)

American Municipal Income Portfolio (XAA)

DESCRIPTION	PAR		FAIR VALUE ¶
(Percentages of each investment category relate to total net assets applicable to outstanding common shares)
Municipal Long-Term Investments — 147.4%
Alabama — 0.8%
Revenue Bond — 0.8%
Camden Industrial Development Board, Weyerhaeuser, Series B (AMT) (Pre-refunded 12/1/13 @ 100), 6.38%, 12/1/24 ¯	$	650,000	$	719,245
Arizona — 5.5%
Revenue Bond — 2.4%
Maricopa County Industrial Development Authority, Health Facilities, Catholic Healthcare West, Series A, 5.25%, 7/1/32		2,000,000		2,098,420
General Obligation — 3.1%
Pima County Unified School District Number 1, Tucson (FGIC) (NATL), 8.38%, 7/1/13		2,450,000		2,694,412
				4,792,832
California — 12.1%
Revenue Bonds — 2.9%
Los Angeles County Metropolitan Transportation Authority, Series B, 5.00%, 6/1/18		750,000		927,570
Pollution Control Financing Authority, Solid Waste Disposal, Waste Management Incorporated Project, Series A-2 (AMT), 5.40%, 4/1/25		1,000,000		1,038,760
State Communities Development Authority, Henry Mayo Newhall Memorial Hospital, Series A (CMI), 5.00%, 10/1/27		500,000		530,715
Ventura County Area Housing Authority, Mira Vista Senior Apartments, Series A (AMBAC) (AMT), 5.00%, 12/1/22 ¥		100,000		91,112
				2,588,157
General Obligations — 8.2%
Los Rios Community College District, Series D, 5.38%, 8/1/34		2,000,000		2,245,980
Poway Unified School District, Series B, Zero Coupon Bond, 5.44%, 8/1/41 °		2,000,000		412,040
Rialto Unified School District, Election 2010, Series A, Convertible (CAB) (AGM), 0.00% through 8/1/26, thereafter, 7.35%, 8/1/41 X		5,000,000		2,478,550
West Contra Costa Unified School District, Election 2010, Series A-1, 5.00%, 8/1/41		2,000,000		2,097,980
				7,234,550
Tax Allocation Bonds — 1.0%
Davis Redevelopment Agency, Series A, 7.00%, 12/1/36		260,000		306,116
Lynwood Redevelopment Agency, Series A, 7.00%, 9/1/31		250,000		288,898
Santee Community Development Commission, Series A, 7.00%, 8/1/31		220,000		253,572
				848,586
				10,671,293
Colorado — 11.3%
Revenue Bonds — 11.3%
State Health Facilities Authority, Covenant Retirement Communities, Series B, 6.13%, 12/1/33		1,000,000		1,022,280
State Health Facilities Authority, Evangelical Lutheran,
5.90%, 10/1/27		650,000		657,410
5.00%, 6/1/29		1,000,000		1,016,780
State Health Facilities Authority, Poudre Valley, Series B (AGM), 5.25%, 3/1/36		2,085,000		2,252,718
State Health Facilities Authority, Valley View Hospital Association, 5.50%, 5/15/28		750,000		796,035
State Health Facilities Authority, Volunteers of America Care, Series A, 5.00%, 7/1/15		280,000		291,729
State Housing & Finance Authority, Solid Waste Disposal, Waste Management Incorporated Project (AMT), 5.70%, 7/1/18		1,000,000		1,134,870
State Housing & Finance Authority, Multifamily Housing Project, Series A-3, Class II (AMT), 5.70%, 10/1/42		2,745,000		2,747,031
Water Reserve & Power Development Authority, Clean Water, Series A, 5.90%, 9/1/16		25,000		25,121
				9,943,974
Florida — 8.7%
Revenue Bonds — 8.7%
City of Cape Coral, Water & Sewer, Series 2011 (AGM), 5.00%, 10/1/41		1,000,000		1,081,440
Miami-Dade County Educational Facilities Authority, University of Miami, Series A, 5.20%, 4/1/24		1,000,000		1,077,960
Miami-Dade County Water & Sewer Systems, (AGM), 5.00%, 10/1/39		1,000,000		1,084,150
Palm Beach County Health Facilities Authority, Abbey Delray South, 5.45%, 10/1/15		1,100,000		1,148,631
Palm Beach County Health Facilities Authority, ACTS Retirement — Life Communities, Series A, 4.50%, 11/15/36		2,120,000		1,945,079

The accompanying notes are an integral part of the financial statements.

4 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

American Municipal Income Portfolio (XAA)

DESCRIPTION	PAR		FAIR VALUE ¶
Palm Beach County Health Facilities Authority, Waterford Project, 5.88%, 11/15/37	$	1,300,000	$	1,335,659
				7,672,919
Georgia — 0.8%
Revenue Bond — 0.8%
Fulton County Development Authority, Maxon Atlantic Station, Fulton Cooling, Series A (AMT) (Optional Put 3/1/15 @ 100), 5.13%, 3/1/26		700,000		705,943
Hawaii — 3.6%
Revenue Bond — 3.6%
State Department of Budget & Finance, Kahala Nui Project, Series A, 8.00%, 11/15/33		3,000,000		3,130,050
Illinois — 6.6%
Revenue Bonds — 4.8%
Metropolitan Pier & Exposition Authority, Capital Appreciation, McCormick, Series A (NATL), Zero Coupon Bond, 5.11%, 12/15/34 °		5,000,000		1,582,900
State Finance Authority, Capital Appreciation, Clare Water Tower, Series B, Zero Coupon Bond, 17.32%, 5/15/50 ¥  °¿		187,500		328
State Finance Authority, Clare Water Tower, Series A, 6.00%, 5/15/28 ¥¿		437,500		65,551
State Finance Authority, Landing at Plymouth Place Project, Series A, 6.00%, 5/15/37 ¥		575,000		484,702
State Finance Authority, Rush University Medical Center, Series B (NATL), 5.25%, 11/1/35		1,000,000		1,043,340
State Finance Authority, Three Crowns Park Plaza, Series A, 5.88%, 2/15/26 ¥		500,000		501,945
State Health Facility Authority, Lutheran General Hospital, Series C, 7.00%, 4/1/14		475,000		504,597
				4,183,363
General Obligation — 1.8%
McCook, 5.20%, 12/1/30		1,500,000		1,630,515
				5,813,878
Indiana — 3.3%
Revenue Bonds — 3.3%
State Health & Educational Facility Financing Authority, Sisters of St. Francis (AGM),
5.25%, 11/1/25		475,000		527,582
5.25%, 11/1/29		530,000		577,377
State Health Facility Financing Authority, Columbus Regional Hospital (AGM), 7.00%, 8/15/15		1,675,000		1,836,688
				2,941,647
Iowa — 1.2%
Revenue Bonds — 1.2%
Sheldon Health Care Facilities, Northwest Iowa Health Center Project, 6.15%, 3/1/16		755,000		757,401
State Higher Education Loan Authority, Wartburg College (ACA) (Pre-refunded 10/1/12 @ 100), 5.50%, 10/1/33 ¯		250,000		257,762
				1,015,163
Kansas — 3.2%
Revenue Bonds — 3.2%
Olathe Health Facilities, Olathe Medical Center, 5.00%, 9/1/29		1,000,000		1,054,030
State Development Finance Authority, Hospital, Adventist Health, 5.50%, 11/15/29		1,540,000		1,776,852
				2,830,882
Kentucky — 4.7%
Revenue Bonds — 4.7%
Louisville & Jefferson County Metropolitan Government, College, Bellarmine University, Series A, 6.00%, 5/1/38		2,500,000		2,683,250
Pikeville Medical Center, 6.50%, 3/1/41		1,250,000		1,443,450
				4,126,700
Maine — 1.2%
Revenue Bond — 1.2%
State Health & Higher Educational Facilities Authority, General Medical Center, 6.75%, 7/1/41		1,000,000		1,084,920
Maryland — 2.8%
General Obligation — 2.8%
Maryland State, 2nd Series, 5.00%, 7/15/20		2,000,000		2,422,180

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 5

Schedule of Investments             February 29, 2012 (unaudited)

American Municipal Income Portfolio (XAA)

DESCRIPTION	PAR		FAIR VALUE ¶
Massachusetts — 6.1%
Revenue Bonds — 6.1%
State Development Financing Agency, Adventcare Project, ¥
6.75%, 10/15/37, Series A	$	650,000	$	652,639
7.63%, 10/15/37		880,000		932,290
State Development Financing Agency, Education Facility, Academy of the Pacific Rim, Series A (ACA), 5.13%, 6/1/31		1,825,000		1,697,067
State Development Financing Agency, Senior Living Facility, Groves — Lincoln, Series A, 7.88%, 6/1/44 ¥		1,000,000		996,330
State Health & Educational Facilities Authority, Suffolk University, Series A, 5.75%, 7/1/39		1,000,000		1,049,910
				5,328,236
Michigan — 1.5%
Revenue Bond — 1.5%
State Strategic Fund, Michigan House of Representatives, Series A (AGC), 5.25%, 10/15/23		1,165,000		1,293,931
Minnesota — 10.4%
Revenue Bonds — 10.4%
Cuyuna Range Hospital District,
5.00%, 6/1/29		1,000,000		1,000,840
5.50%, 6/1/35		1,000,000		1,004,930
Maplewood Multifamily, Carefree Cottages II (AMT) (FNMA) (Mandatory Put 4/15/19 @ 100), 4.80%, 4/15/34		1,000,000		1,022,600
Marshall Medical Center, Avera Marshall Regional Medical Center Project, Series A (Pre-refunded 11/1/13 @100), 6.00%, 11/1/28 ¯		500,000		542,545
St. Louis Park Health Care Facilities, Nicollet Health Services, 5.75%, 7/1/39		2,000,000		2,200,540
St. Paul Housing & Redevelopment Authority, Community Peace Academy Project, Series A, 5.00%, 12/1/36		875,000		749,805
St. Paul Housing & Redevelopment Authority, Health Care Facility, HealthPartners Obligation Group Project, 5.25%, 5/15/36		495,000		506,558
St. Paul Housing & Redevelopment Hospital Authority, Health East Project, 5.00%, 11/15/17		1,400,000		1,420,720
State Agricultural & Economic Development Board, Fairview Health Care System, Series A, 6.38%, 11/15/29		30,000		30,057
Worthington Housing Authority, Meadows Worthington Project, Series A, 5.25%, 11/1/28 ¥		675,000		650,970
				9,129,565
Mississippi — 2.9%
General Obligations — 2.9%
State Development Bank Special Obligation, Jackson,
5.50%, 1/1/23		1,325,000		1,540,829
5.80%, 1/1/24		850,000		994,985
				2,535,814
Missouri — 3.0%
Revenue Bonds — 3.0%
Boone County, Boone Hospital Center, 5.63%, 8/1/38		1,500,000		1,595,730
North Central Regional Water System, 5.00%, 1/1/37 ¥		1,000,000		1,016,250
				2,611,980
Montana — 0.6%
Revenue Bond — 0.6%
Forsyth Pollution Control, Northwestern Corporation (AMBAC), 4.65%, 8/1/23		500,000		536,640
Nebraska — 4.6%
Revenue Bonds — 4.2%
University of Nebraska, Omaha Health & Recreation Project,
5.00%, 5/15/33		1,250,000		1,372,075
5.00%, 5/15/38		2,100,000		2,263,422
				3,635,497
General Obligation — 0.4%
City of Omaha Various Purpose, Series 2011-A, 4.13%, 11/15/31		350,000		376,827
				4,012,324
New Hampshire — 0.7%
Revenue Bond — 0.7%
State Health and Education Facilities Authority, Speare Memorial Hospital, 5.88%, 7/1/34		600,000		617,400

The accompanying notes are an integral part of the financial statements.

6 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

American Municipal Income Portfolio (XAA)

DESCRIPTION	PAR		FAIR VALUE ¶
New Mexico — 0.3%
Revenue Bond — 0.3%
State Mortgage Finance Authority, Series A (FHA) (FMHA) (VA), 6.88%, 1/1/25	$	215,000	$	224,974
North Carolina — 3.1%
Revenue Bond — 1.8%
State Capital Facilities Finance Agency, Meredith College, 6.13%, 6/1/35		1,500,000		1,626,390
General Obligation — 1.3%
Mecklenburg County Public Improvement, Series B, 4.00%, 2/1/23		1,000,000		1,111,930
				2,738,320
Ohio — 1.6%
Revenue Bonds — 1.6%
Miami County Hospital Facilities, Upper Valley Medical Center, 5.25%, 5/15/26		1,000,000		1,050,040
Richland County Hospital Facilities, Medcentral Health System, Series B, 6.38%, 11/15/30		335,000		338,404
				1,388,444
Oregon — 1.3%
Revenue Bond — 1.3%
City of Portland, Sewer System, Second Lien, Series B (NATL), 5.00%, 6/15/24		1,000,000		1,108,780
Pennsylvania — 4.7%
Revenue Bonds — 4.7%
Chartiers Valley Industrial and Commercial Development Authority, Friendship Village South, Series A, 5.75%, 8/15/20		1,000,000		1,001,350
Delaware County College Authority, Neumann College, 6.00%, 10/1/30		1,000,000		1,072,880
Montgomery County Industrial Development Authority, Whitemarsh Continuing Care, 6.25%, 2/1/35		1,000,000		919,180
State Economic Development Financing Authority, Allegheny Energy Supply Company, 7.00%, 7/15/39		1,000,000		1,149,990
				4,143,400
Puerto Rico — 1.8%
Revenue Bond — 1.8%
Puerto Rico Sales Tax Financing Corporation, Series 2011 A-1, 5.00%, 8/1/43		1,500,000		1,593,735
South Carolina — 4.2%
Revenue Bonds — 4.2%
Environmental Improvement, Georgetown County, International Paper, Series A (AMT), 5.55%, 12/1/29		650,000		660,712
State Educational Facilities Authority, Wofford College, Series A, 4.50%, 4/1/30		750,000		776,520
State Jobs Economic Development Authority, Hospital Facilities, Palmetto Health,
6.13%, 8/1/23, Series A		250,000		261,985
6.38%, 8/1/34, Series C (Pre-refunded 8/1/13 @ 100) ¯		40,000		43,410
State Public Service Authority, Santee Cooper, Series A (NATL), 5.00%, 1/1/30		1,800,000		1,991,502
				3,734,129
South Dakota — 7.2%
Revenue Bonds — 7.2%
City of Deadwood, Sales Tax, Series B, 6.25%, 12/1/28 ¥		1,300,000		1,453,764
Sioux Falls Health Facilities, Dow Rummel Village Project, Series A (Pre-refunded 11/15/12 @ 100), 6.63%, 11/15/23 ¯		620,000		644,936
State Economic Development Finance Authority, Pooled Loan Program, Davis Family (AMT), 6.00%, 4/1/29		1,000,000		1,037,220
State Economic Development Finance Authority, Pooled Loan Program, McEleeg, Series B (AMT), 5.95%, 4/1/24		2,000,000		2,088,840
State Health & Educational Facilities Authority, Vocational Education Program (AGC), 5.50%, 8/1/38		1,000,000		1,102,630
				6,327,390
Tennessee — 4.6%
Revenue Bonds — 1.5%
Johnson City Health and Educational Facilities, Mountain States Health, Series A (Pre-refunded 7/1/12 @ 103), 7.50%, 7/1/33 ¯		1,000,000		1,049,090
Shelby County Health, Educational and Housing Facility Board, Methodist Healthcare (Pre-refunded 9/1/12 @ 100), 6.50%, 9/1/21 ¯		240,000		247,620
				1,296,710

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 7

Schedule of Investments             February 29, 2012 (unaudited)

American Municipal Income Portfolio (XAA)

DESCRIPTION	PAR/ SHARES		FAIR VALUE ¶
General Obligations — 3.1%
Shelby County, Series A,
5.00%, 4/1/20	$	1,805,000	$	2,217,424
5.00%, 4/1/20 (Pre-refunded 4/01/19 @ 100) ¯		445,000		558,208
				2,775,632
				4,072,342
Texas — 16.3%
Revenue Bonds — 9.2%
Abilene Health Facilities Development, Sears Methodist Retirement, Series A, 5.88%, 11/15/18		795,000		740,686
Dallas-Fort Worth International Airport Facilities Improvement Corp., Series B, 5.00%, 11/1/35		300,000		326,832
Houston Health Facilities Development, Retirement Facility, Buckingham Senior Living, Series A (Pre-refunded 2/15/14 @ 101), 7.00%, 2/15/26 ¯		1,500,000		1,702,020
North Texas Tollway Authority, First Tier, Series E-3 (Mandatory Put 1/1/16 @ 100), 5.75%, 1/1/38		500,000		580,395
North Texas Tollway Authority, Second Tier, Series F, 5.75%, 1/1/38		1,000,000		1,077,310
Tarrant County Cultural Education, Hendrick Medical Center Project, Series B (AGC), 5.25%, 9/1/26		1,250,000		1,405,837
Tarrant County Cultural Education, Northwest Senior Housing, Edgemere Project, Series A, 6.00%, 11/15/26 ¥		600,000		614,490
Travis County Health Facilities Development Authority, Retirement Facility, Querencia Barton Creek Project, ¥
5.50%, 11/15/25		200,000		191,444
5.65%, 11/15/35		1,600,000		1,448,304
				8,087,318
General Obligations — 7.1%
Humble Independent School District, Series A (AGC), 5.25%, 2/15/22		1,000,000		1,178,570
Plano Independent School District, Series A, 5.25%, 2/15/34		3,500,000		3,904,635
Round Rock Independent School District, 5.00%, 8/1/27		1,000,000		1,143,890
				6,227,095
				14,314,413
Washington — 6.7%
Revenue Bonds — 3.6%
Skagit County Public Hospital District, 6.00%, 12/1/23		900,000		932,634
State Health Care Facilities Authority, Central Washington Health Services, 6.25%, 7/1/24		2,000,000		2,242,420
				3,175,054
General Obligation — 3.1%
State Various Purpose, Series 2011-A, 5.00%, 8/1/30		2,300,000		2,751,582
				5,926,636
Total Municipal Long-Term Investments (Cost: $120,130,132)				129,510,079
Short-Term Investment — 0.8%
Fixed Rate — 0.8%
First American Tax Free Obligations Fund, Class Z , 0.00% W (Cost: $743,908)		743,908		743,908
Total Investments p — 148.2% (Cost: $120,874,040)				130,253,987
Preferred Shares at Liquidation Value — (49.5)%				(43,500,000	)
Other Assets and Liabilities, Net — 1.3%				1,179,926
Total Net Assets Applicable to Outstanding Common Shares — 100.0%			$	87,933,913

The accompanying notes are an integral part of the financial statements.

8 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

American Municipal Income Portfolio (XAA)

¶ Securities are valued in accordance with procedures described in note 2 in Notes to Financial Statements.

¯ Pre-refunded issues are typically backed by U.S. Government obligations, which secure the timely payment of principal and interest. These bonds mature at the call date and price indicated.

¥ Security considered illiquid. As of February 29, 2012, the fair value of these investments was $9,100,119 or 10.3% of total net assets applicable to outstanding common shares. See note 2 in Notes to Financial Statements.

¿ Loan is currently in default with regards to scheduled interest and/or principal payments.

° Zero coupon bonds make no periodic interest payments, but are issued at deep discounts from par value. The rate shown is the effective yield as of February 29, 2012.

X Convertible Capital Appreciation Bonds (Convertible CABs) initially pay no interest but accrete in value from the date of issuance through the conversion date, at which time the bonds start to accrue and pay interest on a semiannual basis until final maturity.

W Investment in affiliated security. This money market fund is advised by U.S. Bancorp Asset Management, Inc., which also serves as advisor for the fund. The rate shown is the annualized seven-day effective yield as of February 29, 2012.

p On February 29, 2012, the cost of investments for federal income tax purposes was approximately $120,874,040. The approximate aggregate gross unrealized appreciation and depreciation of investments, based on this cost, were as follows:

Gross unrealized appreciation	$	10,484,744
Gross unrealized depreciation		(1,104,797	)
Net unrealized appreciation	$	9,379,947

ACA–ACA Financial Guaranty Corporation

AGC–Assured Guaranty Corporation

AGM–Assured Guaranty Municipal Corporation

AMBAC–American Municipal Bond Assurance Corporation

AMT–Alternative Minimum Tax. As of February 29, 2012, the aggregate fair value of securities subject to the AMT was $11,246,333, which represents 12.8% of total net assets applicable to common shares.

CAB–Capital Appreciation Bond

CMI–California Mortgage Insurance Program

FGIC–Financial Guaranty Insurance Corporation

FHA–Federal Housing Administration

FMHA–Farmers Home Administration

FNMA–Federal National Mortgage Association

NATL–National Public Finance Guarantee Corporation

VA–Veterans Administration

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 9

Statement of Assets and Liabilities             February 29, 2012 (unaudited)

Assets:
Unaffiliated investments, at fair value (Cost: $120,130,132) (note 2)	$	129,510,079
Affiliated money market fund, at fair value (Cost: $743,908) (note 5)		743,908
Receivable for accrued interest		1,679,586
Receivable for investments sold		55,041
Prepaid expenses and other assets		29,645
Total assets		132,018,259
Liabilities:
Payable for investments purchased		324,972
Payable for preferred share distributions (note 3)		1,008
Payable for investment advisory fees		36,046
Payable for administration fees		20,598
Payable for audit fees		12,408
Payable for legal fees		7,981
Payable for remarketing agent fees		139,520
Payable for transfer agent fees		27,913
Payable for other expenses		13,900
Total liabilities		584,346
Preferred shares, at liquidation value (note 3)		43,500,000
Net assets applicable to outstanding common shares	$	87,933,913
Net assets applicable to outstanding common shares consist of:
Common shares and additional paid-in capital	$	80,009,101
Undistributed net investment income		721,006
Accumulated net realized loss on investments		(2,176,141	)
Net unrealized appreciation of investments		9,379,947
Net assets applicable to outstanding common shares	$	87,933,913
Net asset value and market price of common shares:
Net assets applicable to outstanding common shares	$	87,933,913
Common shares outstanding (authorized 200 million shares of $0.01 par value)		5,756,267
Net asset value per share	$	15.28
Market price per share	$	15.39
Liquidation preference of preferred shares (note 3):
Net assets applicable to preferred shares	$	43,500,000
Preferred shares outstanding (authorized one million shares)		1,740
Liquidation preference per share	$	25,000

The accompanying notes are an integral part of the financial statements.

10 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

Statement of Operations             For the six-month period ended February 29, 2012 (unaudited)

Investment Income:
Interest from unaffiliated investments	$	3,376,334
Total investment income		3,376,334
Expenses (note 5):
Investment advisory fees		222,604
Administration fees		127,202
Remarketing agent fees		54,937
Custodian fees		3,185
Postage and printing fees		13,102
Transfer agent fees		15,567
Listing fees		11,819
Directors’ fees		46,292
Legal fees		19,216
Audit fees		22,936
Insurance fees		12,523
Pricing fees		3,403
Other expenses		23,192
Total expenses		575,978
Less: Fee reimbursements (note 5)		(478	)
Total net expenses		575,500
Net investment income		2,800,834
Net realized and unrealized gains (losses) on investments (notes 2 and 4)
Net realized gain on investments		175,063
Net change in unrealized appreciation or depreciation of investments		5,743,896
Net gain on investments		5,918,959
Distributions to preferred shareholders (note 2):
From net investment income		(43,785	)
Net increase in net assets applicable to outstanding common shares resulting from operations	$	8,676,008

The accompanying notes are an integral part of the financial statements.

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 11

Statements of Changes in Net Assets

	Six-Month Period Ended 2/29/12 (unaudited)			Year Ended 8/31/11
Operations:
Net investment income	$	2,800,834		$	5,618,740
Net realized gain (loss) on investments		175,063			(13,937	)
Net change in unrealized appreciation or depreciation of investments		5,743,896			(2,878,352	)
Distribution to preferred shareholders from net investment income (note 2)		(43,785	)		(154,037	)
Net increase in net assets applicable to outstanding common shares resulting from operations		8,676,008			2,572,414
Distributions to common shareholders (note 2):
From net investment income		(2,676,664	)		(5,497,235	)
Total increase (decrease) in net assets applicable to outstanding common shares		5,999,344			(2,924,821	)
Net assets applicable to outstanding common shares at beginning of period		81,934,569			84,859,390
Net assets applicable to outstanding common shares at end of period	$	87,933,913		$	81,934,569
Undistributed net investment income	$	721,006		$	640,621

The accompanying notes are an integral part of the financial statements.

12 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

Financial Highlights

Per-share data for an outstanding common share throughout each period and selected information for each period are as follows:

	Six-Month Period  Ended 2/29/12 (unaudited)			Year Ended August 31,
				2011			2010			2009			2008			2007
Per-Share Data
Net asset value, common shares, beginning of period	$	14.23		$	14.74		$	13.05		$	13.55		$	14.40		$	15.46
Operations:
Net investment income		0.49			0.98			0.99			0.99			0.96			1.02
Net realized and unrealized gain (losses) on investments and futures contracts		1.03			(0.50	)		1.71			(0.55	)		(0.54	)		(0.82	)
Distributions to preferred shareholders:
From net investment income		(0.01	)		(0.03	)		(0.03	)		(0.13	)		(0.21	)		(0.25	)
From net realized gain (loss) on investments		—			—			—			—			(0.08	)		(0.03	)
Total from operations		1.51			0.45			2.67			0.31			0.13			(0.08	)
Distributions to common shareholders:
From net investment income		(0.46	)		(0.96	)		(0.98	)		(0.81	)		(0.75	)		(0.86	)
From net realized gain on investments		—			—			—			—			(0.23	)		(0.12	)
Total distributions to common shareholders		(0.46	)		(0.96	)		(0.98	)		(0.81	)		(0.98	)		(0.98	)
Net asset value, common shares, end of period	$	15.28		$	14.23		$	14.74		$	13.05		$	13.55		$	14.40
Market value, common shares, end of period	$	15.39		$	13.60		$	14.89		$	12.37		$	12.84		$	14.74
Selected Information
Total return, common shares, net asset value 1		10.87	%  5		3.47	%		21.27	%		3.13	%		0.95	%		(0.72	)%
Total return, common shares, market value 2		16.90	%  5		(1.97	)%		29.07	%		4.11	%		(6.22	)%		2.56	%
Net assets applicable to outstanding common shares at end of period (in millions)	$	88		$	82		$	85		$	75		$	78		$	83
Ratio of expenses to average weekly net assets applicable to outstanding common shares before fee reimbursements 3		1.37	%  6		1.38	%		1.27	%		1.37	%		1.28	%		1.18	%
Ratio of expenses to average weekly net assets applicable to outstanding common shares after fee reimbursements 3		1.37	%  6		1.37	%		1.26	%		1.37	%		1.28	%		1.17	%
Ratio of net investment income to average weekly net assets applicable to outstanding common shares before fee reimbursements 3		6.69	%  6		7.09	%		7.15	%		8.37	%		6.87	%		6.67	%
Ratio of net investment income to average weekly net assets applicable to outstanding common shares after fee reimbursements 3		6.69	%  6		7.10	%		7.16	%		8.37	%		6.87	%		6.68	%
Portfolio turnover rate		7	%		9	%		10	%		22	%		71	%		24	%
Net assets applicable to remarketed preferred shares, end of period (in millions)	$	44		$	44		$	44		$	44		$	44		$	44
Asset coverage per remarketed preferred share (in thousands) 4	$	76		$	72		$	74		$	68		$	70		$	73
Liquidation preference and market value per remarketed preferred share (in thousands)	$	25		$	25		$	25		$	25		$	25		$	25

¹  Assumes reinvestment of distributions at net asset value.

²  Assumes reinvestment of distributions at actual prices pursuant to the fund’s dividend reinvestment plan.

³  Ratios do not reflect the effect of dividend payments to preferred shareholders; income ratios reflect income earned on assets attributable to preferred shares, where applicable.

⁴  Represents net assets applicable to outstanding common shares plus preferred shares at liquidation value divided by preferred shares outstanding.

⁵  Total return has not been annualized.

⁶  Annualized.

The accompanying notes are an integral part of the financial statements.

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 13

Notes to Financial Statements             (unaudited as to February 29, 2012)

(1) Organization

American Municipal Income Portfolio Inc. (the “fund”) is registered under the Investment Company Act of 1940 (as amended) as a diversified, closed-end management investment company. The fund invests primarily in a diverse range of municipal securities that, at the time of purchase, are rated investment grade or are unrated and deemed to be of comparable quality by one of the fund’s sub-advisors Nuveen Asset Management, LLC (“NAM”). The fund may invest up to 20% of its total assets in municipal securities that, at the time of purchase, are rated lower than investment grade or are unrated and deemed to be of comparable quality by NAM. Municipal securities in which the fund invests may include municipal derivative securities, such as inverse floating rate and inverse interest-only municipal securities, which may be more volatile than traditional municipal securities in certain market conditions. The fund’s investments also may include repurchase agreements, futures contracts, options on futures contracts, options, and interest rate swaps, caps, and floors. Fund shares are listed on the New York Stock Exchange under the symbol XAA.

(2) Summary of
Significant
Accounting
Policies

Security Valuations

Security valuations for the fund’s investments are furnished generally by an independent pricing service that has been approved by the fund’s board of directors. Debt obligations exceeding 60 days to maturity are valued by an independent pricing service that has been approved by the fund’s board of directors. The pricing service may employ methodologies that utilize actual market transactions, broker-dealer supplied valuations, or other formula-driven valuation techniques. These techniques generally consider such factors as yields or prices of bonds of comparable quality, type of issue, coupon, maturity, ratings, and general market conditions. Securities for which prices are not available from an independent pricing service but where an active market exists are valued using market quotations obtained from one or more dealers that make markets in the securities or from a widely-used quotation system. Debt obligations with 60 days or less remaining until maturity may be valued at their amortized cost, which approximates fair value. Investments in open-end funds are valued at their respective net asset values on the valuation date.

The following investment vehicles, when held by the fund, are priced as follows: exchange listed futures and options on futures are priced at their last sale price on the exchange on which they are principally traded, as determined by the fund’s investment advisor, U.S. Bancorp Asset Management, Inc. (“USBAM”), on the day the valuation is made. If there were no sales on that day, futures and options on futures will be valued at the last reported bid price. Options on securities, indices, and currencies traded on Nasdaq or listed on a stock exchange are valued at the last sale price on Nasdaq or on any exchange on the day the valuation is made. If there were no sales on that day, the options will be valued at the last sale price on the previous valuation date. Last sale prices are obtained from an independent pricing service. Swaps and over-the-counter options on securities and indices, are valued at the quotations received from an independent pricing service, if available.

When market quotations are not readily available, securities are internally valued at fair value as determined in good faith by procedures established and approved by the fund’s board of directors. Some of the factors that may be considered in determining fair value are fundamental analytical data relating to the investment; the nature and duration of any restrictions on disposition; trading in similar securities of the same issuer or comparable companies; information from broker-dealers; and an evaluation of the forces that influence the market in which the securities are purchased or sold. If events occur that materially affect the value of securities between the close of trading in those securities and the close of regular trading on the New York Stock Exchange, the securities will be valued at fair value. The use of fair value pricing by the fund may cause the net asset value of its shares to differ significantly from the net asset value that would be calculated without fair value pricing. As of February 29, 2012, the fund held no internally fair valued securities.

Generally accepted accounting principles (“GAAP”) require disclosures regarding the inputs and valuation techniques used to measure fair value and any changes in valuation inputs or technique. These principles establish a three-tier fair value hierarchy for inputs used in measuring fair value. Fair value inputs are summarized in the three broad levels listed below:

Level 1 - Quoted prices in active markets for identical securities.

14 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

Level 2 - Other significant observable inputs (including quoted prices for similar securities, with similar interest rates, prepayment speeds, credit risk, etc.).

Level 3 - Significant unobservable inputs (including the fund’s own assumptions in determining the fair value of investments). Generally, the types of securities included in Level 3 of the fund are securities for which there is limited or no observable fair value inputs available, and as such the fair value is determined through independent broker quotations or management’s fair value procedures established by the fund’s board of directors.

The fair value levels are not necessarily an indication of the risk associated with investing in these investments.

As of February 29, 2012, the fund’s investments were classified as follows:

	Level 1		Level 2		Level 3		Total Fair Value
Investments
Municipal Long-Term Investments	$	—	$	129,510,079	$	—	$	129,510,079
Short-Term Investments		743,908		—		—		743,908
Total Investments	$	743,908	$	129,510,079	$	—	$	130,253,987

Refer to the Schedule of Investments for further security classification.

During the six-month period ended February 29, 2012 the fund recognized no transfers between fair value levels.

Security Transactions and Investment Income

For financial statement purposes, the fund records security transactions on the trade date of the security purchase or sale. Dividend income is recorded on the ex-dividend date. Interest income, including accretion of bond discounts and amortization of bond premiums, is recorded on an accrual basis. Security gains and losses are determined on the basis of identified cost, which is the same basis used for federal income tax purposes. The resulting gain/loss is calculated as the difference between the sales price and the underlying cost of the security on the transaction date.

Distributions to Shareholders

Distributions from net investment income are made monthly for common shareholders and weekly for preferred shareholders. Common share distributions are recorded as of the close of business on the ex-dividend date and preferred share dividends are accrued daily. Net realized gain distributions, if any, will be made at least annually. Distributions are payable in cash or, for common shareholders pursuant to the fund’s dividend reinvestment plan, reinvested in additional common shares of the fund. Under the dividend reinvestment plan, common shares will be purchased in the open market.

Federal Taxes

The fund intends to continue to qualify as a regulated investment company (“RIC”) as provided in Subchapter M of the Internal Revenue Code, as amended, and to distribute all taxable income, if any, to its shareholders. Accordingly, no provision for federal income taxes is required.

As of February 29, 2012, the fund did not have any tax positions that did not meet the “more-likely-than-not” threshold of being sustained by the applicable taxing authority. Generally, tax authorities can examine all the tax returns filed for the last three years.

Net investment income and net realized gains and losses may differ for financial statement and tax purposes because of temporary or permanent book/tax differences. These differences are primarily due to deferred straddle losses. To the extent these differences are permanent, reclassifications are made to the appropriate capital accounts in the fiscal period in which the differences arise.

The character of distributions made during the fiscal period from net investment income or net realized gains may differ from its ultimate characterization for federal income tax purposes. In addition, due to the timing of dividend

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 15

Notes to Financial Statements

distributions, the fiscal period in which amounts are distributed may differ from the fiscal period that the income or realized gains or losses were recorded by the fund.

The character of common and preferred share distributions paid during the six-month period ended February 29, 2012 (estimated) and the fiscal year ended August 31, 2011, were as follows:

	2/29/12		8/31/11
Distributions paid from:
Tax exempt income	$	2,720,449	$	5,644,035
Ordinary income		—		9,198
	$	2,720,449	$	5,653,233

As of August 31, 2011, the fund’s most recently completed fiscal year-end, the components of accumulated earnings on a tax basis were as follows:

Undistributed ordinary income	$	6,792
Undistributed tax-exempt income		640,323
Accumulated capital and post-October losses		(2,330,580	)
Unrealized appreciation		3,615,426
Other accumulated loss		(6,493	)
Accumulated earnings	$	1,925,468

For federal income tax purposes, the fund had capital loss carryovers at August 31, 2011, the fund’s most recently completed fiscal year-end, which, if not offset by subsequent capital gains, will expire on the fund’s fiscal year-ends as follows:

Capital Loss Carryover		Expiration
$	732,181		2017
	1,496,362		2018
	79,991		2019
$	2,308,534

The fund incurred losses of $22,046 for the period from November 1, 2010 to August 31, 2011. As permitted by tax regulations, the fund intends to elect to defer and treat those losses as arising in the fiscal year ended August 31, 2012.

Derivatives

The fund may invest in derivative financial instruments in order to manage risk or gain exposure to various other investments or markets. The fund’s investment objective allows the fund to enter into various types of derivative contracts, including, but not limited to, futures contracts, options on futures contracts, options, and interest rate swaps, caps, and floors. Derivatives may contain various risks including the potential inability of the counterparty to fulfill their obligations under the terms of the contract, the potential for an illiquid secondary market, and the potential for market movements that may expose the fund to gains or losses in excess of the amounts shown on the Statement of Assets and Liabilities. As of February 29, 2012, the fund had no outstanding derivative contracts.

Futures Transactions

In order to protect against changes in interest rates, the fund may buy and sell interest rate futures contracts. Upon entering into a futures contract, the fund is required to deposit cash or pledge U.S. Government securities. The margin required for a futures contract is set by the exchange on which the contract is traded. Subsequent payments, which are dependent on the daily fluctuations in the value of the underlying security or securities, are made or received by the fund each day (daily variation margin) and recorded as unrealized gains (losses) until the contract is closed. When the contract is closed, the fund records a realized gain (loss) equal to the difference between the proceeds from (or cost of) the closing transaction and the fund’s basis in the contract.

16 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

Risks of entering into futures contracts, in general, include the possibility that there will not be a perfect price correlation between the futures contracts and the underlying securities. Second, it is possible that a lack of liquidity for futures contracts could exist in the secondary market, resulting in an inability to close a futures position prior to its maturity date. Third, the purchase of a futures contract involves the risk that the fund could lose more than the original margin deposit required to initiate a futures transaction. These contracts involve market risk in excess of the amount reflected in the fund’s Statement of Assets and Liabilities. Unrealized gains (losses) on outstanding positions in futures contracts held at the close of the period will be recognized as capital gains (losses) for federal income tax purposes. As of and for the six-month period ended February 29, 2012, the fund had no outstanding futures contracts.

Securities Purchased on a When-Issued Basis

Delivery and payment for securities that have been purchased by the fund on a when-issued or forward-commitment basis can take place a month or more after the transaction date. Such securities do not earn interest, are subject to market fluctuation, and may increase or decrease in value prior to their delivery. The fund segregates assets with a market value equal to or greater than the amount of its purchase commitments. The purchase of securities on a when-issued or forward-commitment basis may increase the volatility of the fund’s net asset value if the fund makes such purchases while remaining substantially fully invested. As of February 29, 2012, the fund had no outstanding when-issued or forward-commitment securities.

In connection with the ability to purchase securities on a when-issued basis, the fund may also enter into dollar rolls in which the fund sells securities purchased on a forward-commitment basis and simultaneously contracts with a counterparty to repurchase similar (same type, coupon, and maturity), but not identical securities on a specified future date. As an inducement for the fund to “rollover” its purchase commitments, the fund receives negotiated amounts in the form of reductions of the purchase price of the commitment. Dollar rolls are considered a form of leverage. As of February 29, 2012, the fund had no dollar roll transactions.

Illiquid or Restricted Securities

A security may be considered illiquid if it lacks a readily available market. Securities are generally considered liquid if they can be sold or disposed of in the ordinary course of business within seven days at approximately the value at which the security is valued by the fund. Illiquid securities may be valued under methods approved by the fund’s board of directors as reflecting fair value. Illiquid securities may include restricted securities, which are often purchased in private placement transactions, are not registered under the Securities Act of 1933, and may have contractual restrictions on resale.

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 17

Notes to Financial Statements

As of February 29, 2012, the fund held 14 illiquid securities, the fair value of which was $9,100,119, which represents 10.3% of total net assets applicable to outstanding common shares. As of February 29, 2012, there were no restricted securities. Information concerning illiquid securities, including restricted securities considered to be illiquid, is as follows:

Security	Par		Date Acquired		Cost Basis
City of Deadwood, Sales Tax, Series B, 6.25%, 12/1/28	$	1,300,000		06/09	$	1,280,003
North Central Regional Water System, 5.00%, 1/1/37		1,000,000		12/06		997,156
State Development Financing Agency, Adventcare Project, Series A, 6.75%, 10/15/37, Series A		650,000		10/07		648,405
State Development Financing Agency, Adventcare Project, 7.63%, 10/15/37		880,000		07/10		867,673
State Development Financing Agency, Senior Living Facility, Groves — Lincoln, Series A, 7.88%, 6/1/44		1,000,000		11/09		985,584
State Finance Authority, Capital Appreciation, Clare Water Tower, Series B, Zero Coupon Bond, 15.33%, 5/15/50		187,500		11/05		6,061
State Finance Authority, Clare Water Tower, Series A, 6.00%, 5/15/28		437,500		11/05		601,421
State Finance Authority, Landing at Plymouth Place Project, Series A, 6.00%, 5/15/37		575,000		11/05		572,011
State Finance Authority, Three Crowns Park Plaza, Series A, 5.88%, 2/15/26		500,000		12/08		359,096
Tarrant County Cultural Education, Northwest Senior Housing, Edgemere Project, Series A, 6.00%, 11/15/26		600,000		04/06		612,275
Travis County Health Facilities Development Authority, Retirement Facility, Querencia Barton Creek Project, 5.50%, 11/15/25		200,000		10/05		195,305
Travis County Health Facilities Development Authority, Retirement Facility, Querencia Barton Creek Project, 5.65%, 11/15/25		1,600,000		09/05		1,146,525
Ventura County Area Housing Authority, Mira Vista Senior Apartments, Series A (AMBAC) (AMT), 5.00%, 12/1/22		100,000		07/06		100,000
Worthington Housing Authority, Meadows Worthington Project, Series A, 5.25%, 11/1/28		675,000		05/07		675,000

Inverse Floaters

As part of its investment strategy, the fund may invest in certain securities for which the potential income return is inversely related to changes in a floating interest rate (“inverse floaters”). In general, income on inverse floaters will decrease when short-term interest rates increase and increase when short-term interest rates decrease. Inverse floaters may be characterized as derivative securities and may subject the fund to the risks of reduced or eliminated interest payments and losses of invested principal. In addition, inverse floaters may provide investment leverage. The market values of inverse floaters will generally be more volatile than those of fixed-rate, tax-exempt securities. Therefore, to the extent the fund invests in inverse floaters, the net asset value of the fund’s shares may be more volatile than if the fund did not invest in such securities. As of February 29, 2012, the fund had no outstanding investments in inverse floaters.

Repurchase Agreements

For repurchase agreements entered into with certain broker-dealers, the fund, along with other affiliated registered investment companies, may transfer uninvested cash balances into a joint trading account, the daily aggregate balance of which is invested in repurchase agreements secured by U.S. Government or agency obligations. Securities pledged as collateral for all individual and joint repurchase agreements are held by the fund’s custodian bank until maturity of the repurchase agreement. All agreements require that the daily market value of the collateral be in excess of the repurchase amount, including accrued interest, to protect the fund in the event of a default. As of February 29, 2012, the fund had no outstanding repurchase agreements.

Deferred Compensation Plan

Prior to January 1, 2011, non-interested directors of the First American Family of Funds were able to defer receipt of part or all of their annual compensation under a Deferred Compensation Plan (the “Plan”). Deferred amounts were treated as though equivalent dollar amounts had been invested in shares of open-end First American Funds, as designated by each director. The Plan was terminated effective December 31, 2010. All amounts held in the

18 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

Plan are 100% vested and outstanding account balances under the Plan are obligations of the funds into which amounts were deferred. Deferred amounts remain in the funds until distributed in accordance with the Plan.

Use of Estimates in the Preparation of Financial Statements

The preparation of financial statements, in conformity with GAAP, requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the results of operations during the reporting period. Actual results could differ from these estimates.

Events Subsequent to Period End

Management has evaluated fund-related events and transactions that occurred subsequent to February 29, 2012, through the date of issuance of the fund’s semiannual financial statements. There were no events or transactions that occurred during this period that materially impacted the amounts or disclosures in the fund’s financial statements.

(3) Remarketed
Preferred
Shares      

As of February 29, 2012, the fund had 1,740 remarketed preferred shares (870 shares in Class “T” and 870 shares in Class “TH”) (“RP^® shares”) outstanding with a liquidation preference of $25,000 per share. The dividend rate on the RP^® shares is adjusted every seven days (on Tuesdays for Class “T” and on Thursdays for Class “TH”), as determined by the remarketing agent, agent, Merrill Lynch & Co. Inc (the “Remarketing Agent”).

Normally, the dividend rates on the RP^® shares are set at the market clearing rate determined through a remarketing process that brings together bidders who wish to buy RP^® shares and holders of RP^® shares who wish to sell. Since February 14, 2008, however, sell orders have exceeded bids and the regularly scheduled remarketings for the fund’s RP^® shares have failed. When a remarketing fails, the fund is required to pay the maximum applicable rate on the RP^® shares to holders of such shares for successive dividend periods until such time as the shares are successfully remarketed. The maximum applicable rate on the RP^® shares is 110% of the higher of (1) the applicable AA Composite Commercial Paper Rate or (2) 90% of the Taxable Equivalent of the Short-Term Municipal Bond Rate.

During any dividend period, the maximum applicable rate may be higher than the dividend rate that would have been set had the remarketing been successful. This increases the fund’s cost of leverage and reduces the fund’s common share earnings. On February 29, 2012, the maximum applicable rates were 0.23% for Class “T” and 0.24% for Class “TH”.

In the event of a failed remarketing, holders of RP^® shares will continue to receive dividends at the maximum applicable rate, but generally will not be able to sell their shares until the next successful remarketing. There is no way to predict when or if future remarketings might succeed in attracting sufficient buyers for the shares offered.

RP^® is a registered trademark of the Remarketing Agent.

(4) Investment
Security
Transactions

Cost of purchases and proceeds from sales of securities, other than temporary investments in short-term securities, for the six-month period ended February 29, 2012, aggregated $9,161,504 and $9,412,723, respectively.

(5) Fees and
Expenses

Investment Advisory Fees

Pursuant to an investment advisory agreement, USBAM, a subsidiary of U.S. Bank National Association (“U.S. Bank”), manages the fund’s assets and furnishes related office facilities, equipment, research, and personnel. The agreement provides USBAM with a monthly investment advisory fee in an amount equal to an annualized rate of 0.35% of the fund’s average weekly net assets including preferred shares. For its fee, USBAM provides investment advice and, in general, conducts the management and investment activities of the fund.

The fund may invest in related money market funds that are series of First American Funds, Inc., subject to certain limitations. In order to avoid the payment of duplicative investment advisory fees to USBAM, which acts as the investment advisor to both the fund and the related money market funds, USBAM will reimburse the fund an

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 19

Notes to Financial Statements

amount equal to the investment advisory fee received from the related money market funds that is attributable to the assets of the fund. These reimbursements, if any, are disclosed as “Fee reimbursements” in the Statement of Operations.

NAM and Nuveen Fund Advisors, Inc. (“NFA”) each serve as investment sub-advisor to the fund pursuant to separate investment sub-advisory agreements with USBAM. NAM makes investment decisions for the fund, places purchase and sale orders for the fund’s portfolio transactions, and employs the fund’s portfolio managers and the securities analysts that provide research services relating to the fund. NFA provides certain other investment sub-advisory services to the fund, including assisting in the supervision of the fund’s investment program, risk monitoring, managing the forms and level of leverage employed by the fund, assisting in dividend and distribution level determinations, providing tax advice on issues arising in connection with management of the fund’s portfolio, and assisting with pricing of the fund’s portfolio securities. USBAM pays monthly fees to NAM and NFA for the services provided under their respective sub-advisory agreements with USBAM. USBAM pays NAM and NFA a monthly fee at an annual rate of 0.25% and 0.05%, respectively, based upon average weekly net assets.

Administration Fees

USBAM serves as the fund’s administrator pursuant to an administration agreement between USBAM and the fund. Under this agreement, USBAM receives a monthly administration fee in an amount equal to an annualized rate of 0.20% of the fund’s average weekly net assets including preferred shares. For its fee, USBAM provides numerous services to the fund including, but not limited to, handling the general business affairs, financial and regulatory reporting, and various other services.

Pursuant to a sub-administration agreement between USBAM and NFA, USBAM also pays NFA an annual fee, calculated weekly and paid monthly, equal to 0.05% of the average weekly net assets of the fund for certain administrative and other services that NFA provides to the fund.

Remarketing Agent Fees

The fund has entered into a remarketing agreement with the Remarketing Agent. The remarketing agreement provides the Remarketing Agent with a monthly fee in an amount equal to an annualized rate of 0.25% of the fund’s average amount of RP^® outstanding. For its fee, the Remarketing Agent will remarket shares of RP^® tendered to it on behalf of shareholders and will determine the applicable dividend rate for each seven-day dividend period.

Custodian Fees

U.S. Bank serves as the fund’s custodian pursuant to a custodian agreement with the fund. The custodian fee charged to the fund is equal to an annual rate of 0.005% of average weekly net assets, including preferred shares. These fees are computed weekly and paid monthly.

Under this agreement, interest earned on uninvested cash balances is used to reduce a portion of the fund’s custodian expenses. These credits, if any, are disclosed as “Indirect payments from custodian” in the Statement of Operations. Conversely, the custodian charges a fee for any cash overdrafts incurred, which will increase the fund’s custodian expenses.

For the six-month period ended February 29, 2012, custodian fees were increased by $165 as a result of overdrafts and reduced by $8 as a result of interest earned.

Other Fees and Expenses

In addition to the investment advisory, administrative, remarketing agent, and custodian fees, the fund is responsible for paying most other operating expenses, including: outside directors’ fees and expenses, listing fees, postage and printing of shareholder reports, transfer agent fees and expenses, legal, auditing and accounting services, insurance, pricing, interest, taxes, and other miscellaneous expenses.

For the six-month period ended February 29, 2012, legal fees and expenses of $3,971 were paid to a law firm of which an Assistant Secretary of the fund is a partner.

20 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

Expenses that are directly related to the fund are charged directly to the fund. Other operating expenses of the First American Family of Funds are allocated to the fund on several bases, including evenly across all funds, allocated based on relative net assets of all funds within the First American Family of Funds, or a combination of both methods.

(6) Indemnifications

The fund enters into contracts that contain a variety of indemnifications. The fund’s maximum exposure under these arrangements is unknown. However, the fund has not had prior claims or losses pursuant to these contracts and expects the risk of loss to be remote.

(7) New Accounting
Pronouncements

In May 2011, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) No. 2011-04 “Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs.” ASU No. 2011-04 requires additional disclosures regarding fair value measurements. Effective for fiscal years beginning after December 15, 2011, and for interim periods within those fiscal years, entities will need to disclose the following:

1) the amounts of any transfers between Level 1 and Level 2 and the reasons for those transfers, and

2) for Level 3 fair value measurements, quantitative information about the significant unobservable inputs used, a description of the entity’s valuation processes, and a narrative description of the sensitivity of the fair value measurement to changes in the unobservable inputs and the interrelationship between inputs.

(8) Nuveen
Acquisition

On December 31, 2010, USBAM and its parent company, U.S. Bank, sold a portion of USBAM’s asset management business to Nuveen Investments, Inc. (“Nuveen”). Included in the sale was that part of USBAM’s asset management business that advised the First American equity, fixed income, and asset allocation open-end funds, not including the First American money market funds or the First American closed-end funds (the “Closed-End Funds”). USBAM continues to serve as investment advisor to the First American money market funds and the Closed-End Funds.

On October 7, 2010, the Closed-End Funds’ board of directors considered and approved new investment subadvisory agreements between USBAM and each of NAM and NFA, under which NAM and NFA provide certain investment advisory services to the Closed-End Funds. The sub-advisory agreements were submitted to their respective fund’s shareholders for their approval and took effect on January 1, 2011. There were no changes in the funds’ investment objectives, policies, or expenses as a result of the sub-advisory arrangements between USBAM and NAM and NFA. Douglas J. White, CFA, of Nuveen, continues to serve as lead portfolio manager of American Municipal Income Portfolio.

(9) Regulated
Investment
Company
Modernization
Act

On December 22, 2010, the Regulated Investment Company Modernization Act of 2010 (the “Modernization Act”) became effective. The Modernization Act is the first major piece of legislation affecting RICs since 1986, and it modernizes several of the federal income and excise tax provisions related to RICs. Some highlights of the enacted provisions are as follows:

New capital losses may now be carried forward indefinitely, and retain the character of the original loss. Under preenactment law, capital losses could be carried forward for eight years, and carried forward as short-term capital, irrespective of the character of the original loss.

The Modernization Act contains simplification provisions, which are aimed at preventing disqualification of a RIC for “inadvertent” failures of the asset diversification and/or qualifying income tests. Additionally, the Modernization Act exempts RICs from the preferential dividend rule and repealed the 60-day designation requirement for certain types of pay-through income and gains.

Finally, the Modernization Act contains several provisions aimed at preserving the character of distributions made by a fiscal year RIC during the portion of its taxable year ending after October 31 or December 31, reducing the circumstances under which a RIC might be required to file amended Forms 1099 to restate previously reported distributions.

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 21

Notice to Shareholders             (unaudited)

ANNUAL MEETING RESULTS

An annual meeting of the fund’s shareholders was held on December 6, 2011. Each matter voted upon at the meeting, as well as the number of votes cast for, against or withheld, the number of abstentions, and the number of broker non-votes (if any) with respect to such matters, are set forth below.

(1) The fund’s preferred shareholders were asked to elect two nominees for director at the meeting – Roger A. Gibson and Leonard W. Kedrowski. A quorum of the preferred shares required to vote on this matter was not represented in person or by proxy at the meeting held on December 6, 2011. Because Roger A. Gibson and Leonard W. Kedrowski were previously elected by the preferred shareholders to serve until their successors were elected and qualify, they will continue to serve as directors until they or their successors are elected.

(2) The fund’s common and preferred shareholders, voting as a single class, elected the following directors:

	Shares Voted “For”		Shares Withholding Authority to Vote
John P. Kayser		4,693,830		219,560
Richard K. Riederer		4,690,891		222,499
Joseph D. Strauss		4,693,755		219,635
James M. Wade		4,711,683		201,707

(3) The fund’s common and preferred shareholders, voting as a single class, ratified the selection by the fund’s board of directors of Ernst & Young LLP as the independent registered public accounting firm for the fund for the fiscal period ending August 31, 2012. The following votes were cast regarding this matter:

Shares Voted “For”		Shares Voted “Against”		Abstentions		Broker Non-Votes
	4,796,567		29,074		87,749		—

HOW TO OBTAIN A COPY OF THE FUND’S PROXY VOTING POLICIES AND PROXY VOTING RECORD

A description of the policies and procedures that the fund uses to determine how to vote proxies relating to portfolio securities, as well as information regarding how the fund voted proxies relating to portfolio securities is available at firstamericanfunds.com and on the Securities and Exchange Commission’s website at www.sec.gov. A description of the fund’s policies and procedures is also available without charge, upon request, by calling 800.677.3863.

FORM N-Q HOLDINGS INFORMATION

The fund is required to file its complete schedule of portfolio holdings for the first and third quarters of each fiscal year with the Securities and Exchange Commission on Form N-Q. The fund’s Form N-Q is available (1) without charge upon request by calling 800.677.3863 and (2) on the Securities and Exchange Commission’s website at www.sec.gov. In addition, you may review and copy the fund’s Form N-Q at the Commission’s Public Reference Room in Washington D.C. You may obtain information on the operation of the Public Reference Room by calling 800.SEC.0330.

QUARTERLY PORTFOLIO HOLDINGS

The fund will make portfolio holdings information publicly available by posting the information at firstamericanfunds.com on a quarterly basis. The fund will attempt to post such information within 10 business days of the calendar quarter-end.

22 AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT

First American Funds’ Privacy Policy

We want you to understand what information we collect and how it’s used.

“Nonpublic personal information” is nonpublic information that we obtain while providing financial products or services to you.

How we collect your information

We obtain nonpublic information about you during the account opening process from the applications and other forms you are asked to complete and from the transactions you make with us. We may also receive nonpublic information about you from companies affiliated with us or from other companies that provide services to you. We do not use nonpublic information received from our affiliates for marketing purposes.

Why we collect your information

We gather nonpublic personal information about you and your accounts so that we can:

• Know who you are and prevent unauthorized access to your information.

• Comply with the laws and regulations that govern us.

The types of information we collect

We may collect the following nonpublic personal information about you:

• Information about your identity, such as your name, address, and social security number.

• Information about your transactions with us.

• Information you provide on applications, such as your beneficiaries and banking information, if provided to us.

Confidentiality and security

To protect nonpublic personal information about you, we restrict access to such information to only those employees and authorized agents who need to use the information. We maintain physical, electronic, and procedural safeguards to maintain the confidentiality and security of nonpublic information about you. In addition, we require our service providers to restrict access to nonpublic personal information about you to those employees who need that information in order to provide products or services to you. We also require them to maintain physical, electronic, and procedural safeguards that comply with applicable federal standards and regulations to guard your information.

What information we disclose

We may share some or all of the nonpublic personal information that we collect about you with our affiliated providers of financial services, including our family of funds and their advisor, and with companies that perform marketing services on our behalf.

We’re permitted by law to disclose nonpublic personal information about you to other third parties in certain circumstances. For example, we may disclose nonpublic personal information about you to affiliated and nonaffiliated third parties to assist us in servicing your account (e.g., mailing of fund-related materials) and to government entities (e.g., IRS for tax purposes).

We’ll continue to adhere to the privacy policies and practices described here even after your account is closed or becomes inactive.

Additional rights and protections

You may have other privacy protections under applicable state laws. To the extent that these state laws apply, we will comply with them when we share information about you. This privacy policy does not apply to your relationship with other financial service providers, such as broker-dealers. We may amend this privacy notice at any time, and we will inform you of changes as required by law.

Our pledge applies to products and services offered by

• First American Funds, Inc. • American Strategic Income Portfolio Inc. • American Strategic Income Portfolio Inc. II • American Strategic Income Portfolio Inc. III • American Select Portfolio Inc. • American Municipal Income Portfolio Inc. • Minnesota Municipal Income Portfolio Inc. • First American Minnesota Municipal Income Fund II, Inc. • American Income Fund Inc.

NOT FDIC INSURED NO BANK GUARANTEE MAY LOSE VALUE

AMERICAN MUNICIPAL INCOME PORTFOLIO         2012 SEMIANNUAL REPORT 23

BOARD OF DIRECTORS

Leonard Kedrowski

Chairperson of American Municipal Income Portfolio

Owner and President of Executive and Management Consulting, Inc.

Roger Gibson

Director of American Municipal Income Portfolio

Director of Charterhouse Group, Inc.

John Kayser

Director of American Municipal Income Portfolio

Retired; former Principal of William Blair & Company, LLC

Richard Riederer

Director of American Municipal Income Portfolio

Owner and Chief Executive Officer of RKR Consultants, Inc.

Joseph Strauss

Director of American Municipal Income Portfolio

Owner and President of Strauss Management Company

James Wade

Director of American Municipal Income Portfolio

Owner and President of Jim Wade Homes

American Municipal Income Portfolio’s Board of Directors is comprised entirely of independent directors.

P.O. Box 1330

Minneapolis, MN 55440-1330

American Municipal Income Portfolio

2012 Semiannual Report

U.S. Bancorp Asset Management, Inc., is a wholly owned subsidiary of U.S. Bank National Association, which is a wholly owned subsidiary of U.S. Bancorp.

This document is printed on paper containing 10% postconsumer waste.

4/2012    0021-12    XAA-SAR

Item 2—Code of Ethics

Not applicable to the semi-annual report.

Item 3—Audit Committee Financial Expert

Not applicable to the semi-annual report.

Item 4—Principal Accountant Fees and Services

Not applicable to the semi-annual report.

Item 5—Audit Committee of Listed Registrants

Not applicable to the semi-annual report.

Item 6—Schedule of Investments

The schedule is included as part of the report to shareholders filed under Item 1 of this Form.

Item 7—Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies

Not applicable to the semi-annual report.

Item 8—Portfolio Managers of Closed-End Management Investment Companies

Not applicable to the semi-annual report.

Item 9—Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers

Neither the registrant nor any “affiliated purchaser,” as defined in Rule 10b-18(a)(3) under the Exchange Act, purchased any shares or other units of any class of the registrant’s equity securities that is registered pursuant to Section 12 of the Exchange Act.

Item 10—Submission of Matters to a Vote of Security Holders

There have been no material changes to the procedures by which shareholders may recommend nominees to the registrant’s board of directors, where those changes were implemented after the registrant last provided disclosure in response to the requirements of Item 7(d)(2)(ii)(G) of Schedule 14A, or this item.

Item 11—Controls and Procedures

(a) The registrant’s principal executive officer and principal financial officer have evaluated the effectiveness of the registrant’s disclosure controls and procedures within 90 days of the date of this filing and have concluded that the registrant’s disclosure controls and procedures were effective, as of that date, in ensuring that information required to be disclosed by the registrant in this Form N-CSR was recorded, processed, summarized and reported timely.

(b) There were no changes in the registrant’s internal control over financial reporting that occurred during the 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.

(a)(2) Certifications of the principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Investment Company Act of 1940 are filed as exhibits hereto.

(a)(3) Not applicable.

(b) Certifications of the principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(b) under the Investment Company Act of 1940 are filed as exhibits hereto.

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.

American Municipal Income Portfolio Inc.
By:	/s/    Joseph M. Ulrey III
	Joseph M. Ulrey III
	President

Date: April 30, 2012

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/    Joseph M. Ulrey III
	Joseph M. Ulrey III
	President

Date: April 30, 2012

By:	/s/    Jill M. Stevenson
	Jill M. Stevenson
	Treasurer

Date: April 30, 2012