Ready Assets Government Liquidity Fund N-CSR Certified annual shareholder report (management investment company)

UNITEDSTATES
SECURITIESANDEXCHANGECOMMISSION
Washington,D.C.20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT
INVESTMENT COMPANIES

Investment Company Act file number 811-02556

Name of Fund: Ready Assets Prime Money Fund

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: John M. Perlowski, Chief Executive Officer, Ready Assets
Prime Money Fund, 55 East 52^nd Street, New York, NY 10055

Registrant’s telephone number, including area code: (800) 441-7762

Date of fiscal year end: 04/30/2011

Date of reporting period: 04/30/2011

Item 1 – Report to Stockholders

April 30, 2011

Annual Report

Ready Assets Prime Money Fund

Not FDIC Insured • No Bank Guarantee • May Lose Value

Table of Contents
	Page
Dear Shareholder	3
Annual Report:
Money Market Overview	4
Fund Information	5
Disclosure of Expenses	5
Financial Statements:
Schedule of Investments	6
Statement of Assets and Liabilities	9
Statement of Operations	10
Statements of Changes in Net Assets	11
Financial Highlights	12
Notes to Financial Statements	13
Report of Independent Registered Public Accounting Firm	15
Important Tax Information	15
Officers and Trustees	16
Additional Information	19

2  READY ASSETS PRIME MONEY FUND  APRIL 30, 2011 

Dear Shareholder

Time and again, we have seen how various global events and developing trends can have significant influence on financial markets. I hope you find
that the following review of recent market conditions provides additional perspective on the performance of your investments as you read this share-
holder report.

Over the past 12 months, we have seen a sluggish, stimulus-driven economic recovery at long last gain real traction, accelerate, and transition into
a consumption-driven expansion. For the most part, 2010 was plagued with widely fluctuating economic data, but as the year drew to a close, it
became clear that cyclical stimulus had beaten out structural problems as economic data releases generally became more positive and financial
markets showed signs of continuing improvement. Although the sovereign debt crisis in Europe and high inflation in developing markets that troubled
the global economy in 2010 remain challenges today, overall investor confidence has improved considerably. During the first four months of 2011,
that confidence was shaken by political turmoil in the Middle East/North Africa region, soaring prices of oil and other commodities, tremendous nat-
ural disasters in Japan and a change in the ratings outlook for US debt. However, strong corporate earnings prevailed and financial markets resumed
their course while the global economy continued to garner strength.

Equity markets experienced uneven growth and high volatility in 2010, but ended the year with gains. Following a strong start to 2011, the series of
confidence-shaking events brought spurts of heightened volatility to markets worldwide, but was not enough to derail the bull market. Overall, global
equities posted strong returns over the past 12 months. Emerging market equities, which had outperformed developed markets earlier in the period,
fell prey to heightened inflationary pressures and underperformed developed markets later in the period. In the United States, strong corporate earn-
ings and positive signals from the labor market were sources of encouragement for equity investors, although the housing market did not budge from
its slump. Early in 2011, the US Federal Reserve announced that it would continue its Treasury purchase program (“QE2”) through to completion
and keep interest rates low for an extended period. This compelled investors to continue buying riskier assets, furthering the trend of small cap
stocks outperforming large caps.

While fixed income markets saw yields trend lower (pushing bond prices higher) through most of 2010, the abrupt reversal in investor sentiment
and risk tolerance in the fourth quarter drove yields sharply upward. Global credit markets were surprisingly resilient in the face of recent headwinds
and yields regained relative stability as the period came to a close. Yield curves globally remained steep by historical standards and higher-risk
sectors continued to outperform higher-quality assets. The tax-exempt municipal market enjoyed a powerful rally during the period of low yields in
2010, but when that trend reversed, the market was dealt an additional blow as it became evident that the Build America Bond program would
not be extended. Meanwhile, municipal finance troubles raised credit concerns among investors and tax-exempt mutual funds experienced heavy
outflows, resulting in wider spreads and falling prices. The new year brought relief from these headwinds and a steady rebound in the tax-exempt
municipal market.

Cash investments, as represented by the 3-month Treasury bill, returned only a fraction over 0% for the 12-month period as short-term interest rates
remained low. Yields on money market securities remain near all-time lows.

Risk Assets Rallied on Growing Investor Confidence: Total Returns as of April 30, 2011	6-month	12-month
US large cap equities (S&P 500® Index)	16.36%	17.22%
US small cap equities (Russell2000® Index)	23.73	22.20
International equities (MSCI Europe, Australasia, Far East Index)	12.71	19.18
Emerging market equities (MSCI Emerging Markets Index)	9.74	20.67
3-month Treasury bill (BofA Merrill Lynch 3-Month Treasury Bill Index)	0.09	0.17
US Treasury securities (BofA Merrill Lynch 10-Year US Treasury Index)	(3.85)	6.37
US investment grade bonds (Barclays Capital US Aggregate Bond Index)	0.02	5.36
Tax-exempt municipal bonds (Barclays Capital Municipal Bond Index)	(1.68)	2.20
US high yield bonds (Barclays Capital US Corporate High Yield 2% Issuer Capped Index)	6.18	13.32
Past performance is no guarantee of future results. Index performance shown for illustrative purposes only. You cannot invest directly in an index.

While no one can peer into a crystal ball and eliminate the uncertainties presented by the economic landscape and financial markets, BlackRock
can offer investors the next best thing: partnership with the world’s largest asset management firm that delivers consistent long-term investment
results with fewer surprises. For additional market perspective and investment insight, visit www.blackrock.com/shareholdermagazine, where you’ll
find the most recent issue of our award-winning Shareholder® magazine, as well as its quarterly companion newsletter, Shareholder Perspectives.
As always, we thank you for entrusting BlackRock with your investments, and we look forward to your continued partnership in the months and
years ahead.

THIS PAGE NOT PART OF YOUR FUND REPORT  3 

Money Market Overview

For the Period Ended April 30, 2011

Throughout the 12-month period ended April 30, 2011, the Federal Open Market Committee (FOMC) maintained the target range for the federal funds
rate at 0.00% to 0.25% while remaining consistent in its position that economic conditions were likely to warrant “exceptionally low levels of the fed-
eral funds rate for an extended period.” At its April 27, 2011 meeting, the FOMC determined that “the economic recovery is proceeding at a moderate
pace” and that “conditions in the labor market are improving gradually.” The FOMC also confirmed its intention to continue the policy it announced in
November 2010 to purchase $600 billion of longer-term Treasury securities by the end of June 2011.

Early in May 2010, heightened concerns about sovereign risk in certain peripheral European countries contributed to an increase in financial market
volatility and upward pressure on London Interbank Offered Rate (LIBOR) settings. To improve liquidity conditions in US dollar short-term credit markets
in Europe, the US Federal Reserve reestablished temporary US dollar liquidity swap facilities with the European Central Bank (ECB), while the ECB
established long-term financing operations of various tenors to provide additional liquidity to the market. The European Union, the ECB and the
International Monetary Fund announced a coordinated package of financial aid totaling Euro 750 billion (close to $1 trillion in US dollar terms).
Ultimately, the tone of the short-term credit markets improved, and LIBOR settings stabilized, by the end of June 2010. As part of its continuing efforts
to strengthen the Euro-zone financial system, at its summit held in March 2011, the European Union adopted a preliminary framework to address the
size and scope of financial stability mechanisms, bank stress tests, fiscal reform, and surveillance of macroeconomic imbalances.

In April 2011, the ECB raised its key interest rate by 0.25% to 1.25%. This move makes the ECB among the first of the developed world’s major central
banks to initiate a cycle of raising rates since financial markets initially tightened under the global credit crisis. Short-dated LIBOR settings finished the
period unchanged on a year-over-year basis. The slope of the LIBOR curve as measured from one month to one year, flattened by 19 basis points, led
by a decline in the one-year LIBOR setting.

Early in 2011, the US Treasury announced its intention to gradually reduce the amount of Treasury bills issued through the Supplementary Financing
Program from $200 billion to $5 billion as the national debt threatens to reach the statutory limit. In addition, large-scale asset purchases by the US
Federal Reserve have reduced the amount of securities available to collateralize repurchase agreements. The tightening in supply of Treasury bills and
overnight repurchase agreements drove rates down on those instruments toward the end of the period.

In the tax-exempt space, historically low rates resulted in an overall decline in money fund assets over the past 12 months. The seven-day Securities
Industry and Financial Markets Association Index remained in a tight range around 0.27%, its average rate for the annual period.

While tax-exempt money market funds, which are comprised primarily of municipal variable rate demand notes (VRDNs), experienced declining assets
during the period, non-traditional buyers stepped into the tax-exempt market, which kept dealer inventories low and manageable. Non-traditional buy-
ers were drawn to the favorable yields offered on VRDNs, which served as an attractive alternative to asset-backed commercial paper, where supply
had dwindled. Demand for VRDNs was further supported by recent regulatory amendments requiring higher levels of liquidity in money market funds.

Although municipal issuers have limited the new supply of VRDNs, the market has turned its focus to the expiration of bank commitments enhancing
over $100 billion of outstanding municipal VRDNs in 2011. As of this writing, issuers have been replacing the expiring commitments according to
schedule and without difficulty. Additional banks are increasing their participation in the space, which provides better diversification for municipal
money market funds.

State and local governments continued to struggle with budget shortfalls and reduced their overall issuance of municipal notes. The one-year municipal
yield remained relatively stable throughout the period, hovering around 0.38%, as measured by Thomson Municipal Market Data.

Past performance is no guarantee of future results. Index performance shown for illustrative purposes only. You cannot invest directly in an index.

4  READY ASSETS PRIME MONEY FUND  APRIL 30, 2011 

Fund Information as of April 30, 2011

Investment Objective

Ready Assets Prime Money Fund’s (the “Fund”) investment objective is to seek preservation of capital, liquidity and the highest possible current
income consistent with this objective available from investing in a diversified portfolio of short-term money market securities.

Current Seven-Day Yields
	7-Day	7-Day
	SEC Yield	Yield
As of April 30, 2011	0.00%	0.00%

The 7-Day SEC yield may differ from the 7-Day yield shown above due to the fact
that the 7-Day SEC yield excludes distributed capital gains.
Past performance is not indicative of future results.

Portfolio Composition
	Percent of
	Net Assets
Certificates of Deposit	35%
Commercial Paper	31
U.S. Treasury Obligations	12
U.S. Government Sponsored Agency Obligations	8
Municipal Bonds	7
Repurchase Agreements	5
Corporate Notes	2
Total	100%

Disclosure of Expenses

Shareholders of this Fund may incur the following charges: (a) expenses
related to transactions, including sales charges and exchange fees; and
(b) operating expenses including advisory fees, distribution fees including
12b-1 fees, and other Fund expenses. The expense example below (which
is based on a hypothetical investment of $1,000 invested on November 1,
2010 and held through April 30, 2011) is intended to assist shareholders
both in calculating expenses based on an investment in the Fund and
in comparing these expenses with similar costs of investing in other
mutual funds.

The table below provides information about actual account values and
actual expenses. In order to estimate the expenses a shareholder paid
during the period covered by this report, shareholders can divide their
account value by $1,000 and then multiply the result by the number
under the heading entitled “Expenses Paid During the Period.”

The table also provides information about hypothetical account values
and hypothetical expenses based on the Fund’s actual expense ratio and
an assumed rate of return of 5% per year before expenses. In order to
assist shareholders in comparing the ongoing expenses of investing in this
Fund and other funds, compare the 5% hypothetical example with the 5%
hypothetical examples that appear in other funds’ shareholder reports.

The expenses shown in the table are intended to highlight shareholders’
ongoing costs only and do not reflect any transactional expenses, such
as sales charges or exchange fees. Therefore, the hypothetical example is
useful in comparing ongoing expenses only, and will not help shareholders
determine the relative total expenses of owning different funds. If these
transactional expenses were included, shareholder expenses would have
been higher.

		Actual			Hypothetical2
	Beginning	Ending		Beginning	Ending		Annualized
	Account Value	Account Value	Expenses Paid	Account Value	Account Value	Expenses Paid	Expense
	November 1, 2010	April 30, 2011	During the Period1	November 1, 2010	April 30, 2011	During the Period1	Ratio
Ready Assets Prime
Money Fund	$1,000.00	$1,000.00	$1.79	$1,000.00	$1,023.01	$1.81	0.36%

¹ Expenses are equal to the Fund's annualized expense ratio, multiplied by the average account value over the period, multiplied by 181/365 (to reflect the one-half year
period shown).
² Hypothetical 5% annual return before expenses is calculated by pro rating the number of days in the most recent fiscal half year divided by 365.

READY ASSETS PRIME MONEY FUND  APRIL 30, 2011  5 

Schedule of Investments April 30, 2011
 (Percentages shown are based on Net Assets)

		Par
Certificates of Deposit		(000)	Value
Domestic — 0.9%
State Street Bank & Trust Co., 0.25%, 5/11/11	$ 30,000		$ 30,000,000
Yankee — 33.6% (a)
BNP Paribas SA, NY:
0.39%, 5/05/11		30,000	30,000,000
0.36%, 6/13/11		51,000	51,000,000
0.36%, 8/05/11		25,000	25,000,000
Bank of Montreal, Chicago (b):
0.26%, 8/29/11		14,000	14,000,000
0.29%, 1/25/12		15,000	15,000,000
Bank of Nova Scotia, Houston:
0.27%, 5/03/11		35,000	35,000,000
0.27%, 5/25/11		25,000	25,000,000
0.27%, 6/03/11		45,000	45,000,000
0.26%, 6/10/11		35,000	35,000,000
Bank of Tokyo-Mitsubishi UFJ Ltd., NY, 0.25%, 5/16/11		24,000	24,000,000
Canadian Imperial Bank of Commerce, NY,
0.27%, 7/18/11 (b)		21,560	21,560,000
Credit Agricole CIB, NY:
0.30%, 6/01/11		40,000	40,000,000
0.25%, 6/03/11		35,000	35,000,000
Deutsche Bank AG, NY:
0.31%, 6/17/11		20,000	20,000,000
0.31%, 8/04/11 (b)		30,000	30,000,000
0.31%, 10/03/11		25,000	25,000,000
Dexia Credit Local, NY, 0.41%, 6/01/11 (c)		36,145	36,145,000
Lloyd's TSB Bank Plc, NY:
0.25%, 6/02/11		34,000	34,000,000
0.32%, 8/02/11 (c)		36,735	36,735,000
Mizuho Corporate Bank, NY, 0.25%, 5/18/11		50,000	50,000,000
National Australia Bank, NY, 0.32%, 2/10/12 (b)		17,000	17,000,000
Rabobank Nederland NV, NY:
0.31%, 9/15/11 (b)		30,000	30,000,000
0.34%, 10/05/11		35,000	35,000,000
Royal Bank of Canada, NY (b):
0.27%, 10/14/11		30,000	30,000,000
0.31%, 2/29/12		34,000	34,000,000
Royal Bank of Scotland Plc, CT:
0.66%, 8/02/11 (c)		11,000	11,000,000
0.52%, 9/19/11		64,000	64,000,000
Societe Generale, NY, 0.29%, 8/01/11		33,000	33,000,000
Svenska Handelsbanken AB, NY, 0.27%, 6/15/11		22,000	22,000,000
Toronto-Dominion Bank, NY:
0.25%, 6/07/11		24,000	24,000,000
0.33%, 9/06/11		20,000	20,000,000
0.31%, 1/12/12 (b)		17,500	17,500,000
UBS AG, Stamford (b):
0.35%, 10/04/11		32,580	32,580,000
0.35%, 10/11/11		36,765	36,765,000
Westpac Banking Corp., NY (b):
0.33%, 11/04/11		35,000	35,000,000
0.32%, 12/09/11		35,000	35,000,000
			1,104,285,000
Total Certificates of Deposit — 34.5%			1,134,285,000

		Par
Commercial Paper		(000)	Value
Alpine Securitization Corp. (d):
0.17%, 5/11/11	$ 8,000		$ 7,999,660
0.21%, 6/01/11		15,000	14,997,375
Amsterdam Funding Corp., 0.28%, 6/20/11 (d)		25,000	24,990,472
Antalis U.S. Funding Corp. (d):
0.26%, 5/16/11		11,570	11,568,830
0.32%, 6/30/11		20,000	19,989,511
Argento Variable Funding Co. LLC, 0.32%, 6/28/11 (d)(e)		35,000	34,982,267
Atlantic Asset Securitization Corp., 0.21%, 5/05/11 (d)		15,000	14,999,737
Bank of America Corp. (d):
0.12%, 5/02/11		35,000	35,000,000
0.10%, 5/04/11		35,000	34,999,806
Cancara Asset Securitization LLC (d):
0.19%, 5/26/11		30,000	29,996,200
0.27%, 7/06/11		14,000	13,993,175
Commonwealth Bank of Australia, 0.32%, 10/06/11 (b)		35,000	34,998,273
Credit Suisse, 0.20%, 7/14/11 (d)		26,000	25,989,456
DNB Nor Bank ASA, 0.27%, 7/05/11 (d)(e)		29,000	28,986,080
Falcon Asset Securitization Corp. (d):
0.26%, 5/26/11		12,000	11,997,920
0.25%, 6/07/11		21,000	20,994,750
Govco LLC, 0.29%, 5/16/11 (d)		25,000	24,997,181
LMA Americas LLC, 0.22%, 6/29/11 (d)		25,000	24,991,139
Manhattan Asset Funding Co., LLC (d):
0.28%, 5/05/11		30,000	29,999,300
0.26%, 5/06/11		19,000	18,999,451
0.25%, 5/11/11		11,000	10,999,313
0.26%, 5/12/11		10,000	9,999,273
Matchpoint Master Trust, 0.18%, 5/19/11 (e)		19,000	18,998,385
MetLife Short Term Funding LLC (d):
0.15%, 5/02/11		2,000	2,000,000
0.28%, 5/23/11		20,000	19,996,733
0.28%, 6/01/11		24,000	23,994,400
0.22%, 7/18/11		80,000	79,961,607
Mont Blanc Capital Corp., 0.17%, 5/18/11 (d)		20,000	19,998,489
Natixis U.S. Finance Company, LLC, 0.26%, 7/01/11 (d)		7,000	6,996,967
Nieuw Amsterdam Receivables Corp. (d):
0.28%, 6/01/11		20,000	19,995,333
0.28%, 6/27/11		15,500	15,493,249
0.26%, 7/08/11		21,000	20,989,838
0.25%, 7/12/11		5,000	4,997,535
Scaldis Capital LLC, 0.24%, 5/09/11 (d)		15,000	14,999,300
Solitaire Funding LLC (d):
0.22%, 5/11/11		10,000	9,999,450
0.21%, 5/16/11		37,000	36,996,978
Starbird Funding Corp. (d):
0.10%, 5/02/11		9,000	9,000,000
0.20%, 5/09/11		50,000	49,998,056
Surrey Funding Corp., 0.24% — 0.25%, 5/02/11 (d)		27,615	27,615,000
Thunder Bay Funding LLC, 0.18%, 5/09/11 (d)		13,215	13,214,537
Victory Receivables Corp. (d):
0.25%, 5/23/11		25,000	24,996,354
0.25%, 5/25/11		12,000	11,998,083

Portfolio Abbreviations
To simplify the listing of portfolio holdings in the Schedule of Investments, the		COP	Certificates of Participation
names and descriptions of many of the securities have been abbreviated according		HFA	Housing Finance Agency
to the following list:		HRB	Housing Revenue Bonds
AGM	Assured Guaranty Municipal Corp.	LOC	Letter of Credit
AMT	Alternative Minimum Tax (subject to)	RB	Revenue Bonds
		SBPA	Stand-by Purchase Agreement
See Notes to Financial Statements.		VRDN	Variable Rate Demand Notes

6  READY ASSETS PRIME MONEY FUND  APRIL 30, 2011 

Schedule of Investments (continued)
(Percentages shown are based on Net Assets)

		Par
Commercial Paper (concluded)		(000)	Value
Westpac Banking Corp. (b)(e):
0.32%, 1/06/12	$ 36,000		$ 36,000,000
0.42%, 1/13/12		35,000	35,000,000
Windmill Funding Corp., 0.28%, 6/20/11 (d)		21,000	20,991,997
Total Commercial Paper — 30.7%			1,010,701,460
Corporate Notes
JPMorgan Chase Bank, NA, 0.30%, 5/18/12 (b)		37,160	37,160,000
KBC Bank NV, NY, 1.90%, 6/01/11 (c)		27,600	27,600,000
Total Corporate Notes — 2.0%			64,760,000
Municipal Bonds (c)
Bay Area Toll Authority, RB, VRDN, San Francisco
Bay Area, Series E-3 (Bank of America NA LOC),
0.19%, 5/06/11		20,000	20,000,000
California Health Facilities Financing Authority, RB,
VRDN, Scripps Health, Series B (JPMorgan Chase
Bank LOC), 0.22%, 5/06/11		14,000	14,000,000
California HFA, RB, VRDN, AMT (Fannie Mae LOC,
Freddie Mac LOC), Home Mortgage:
Series F, 0.28%, 5/06/11		23,000	23,000,000
Series U, 0.23%, 5/06/11		15,000	15,000,000
California Pollution Control Financing Authority,
Refunding RB, VRDN, Pacific Gas & Electric Co.,
Series E (JPMorgan Chase Bank LOC), 0.22%, 5/02/11		8,300	8,300,000
Indiana Finance Authority, Refunding RB, VRDN,
Sisters of St. Francis, Series B (JPMorgan Chase Bank
LOC), 0.24%, 5/06/11		6,000	6,000,000
Los Angeles Community Redevelopment Agency California,
RB, VRDN, Hollywood & Vine Apartments, Series A, AMT
(Fannie Mae Liquidity Facility), 0.25%, 5/06/11		13,000	13,000,000
Metropolitan Transportation Authority, Refunding RB,
VRDN, Series B (AGM Insurance, Dexia Credit Local
SBPA), 0.75%, 5/06/11		20,000	20,000,000
New Jersey Transportation Trust Fund Authority, RB,
VRDN, Transportation System, Series C (JPMorgan
Chase Bank LOC), 0.24%, 5/06/11		8,000	8,000,000
New York City Industrial Development Agency, RB, VRDN,
USA Waste Services, New York City Project, AMT
(JPMorgan Chase Bank LOC), 0.24%, 5/06/11		9,600	9,600,000
New York State HFA, HRB, VRDN, Series A, AMT (Fannie
Mae Liquidity Facility), 0.23%, 5/06/11		22,900	22,900,000
New York State HFA, RB, VRDN, AMT (Fannie Mae
Liquidity Facility):
125 West 31st Street Housing, Series A,
0.23%, 5/06/11		13,000	13,000,000
East 39th Street Housing, Series A, 0.23%, 5/06/11		16,000	16,000,000
316 11th Avenue Housing, Series A, 0.23%, 5/06/11		21,500	21,500,000
New York State HFA, Refunding RB, VRDN, Series L
(Bank of America NA LOC), 0.25%, 5/06/11		10,500	10,500,000
Palm Beach County School District, COP, VRDN, Series B
(AGM Insurance, Dexia Credit Local SBPA),
0.80%, 5/06/11		5,000	5,000,000

	Par
Municipal Bonds (c) (concluded)	(000)	Value
Westchester County Healthcare Corp. New York, RB,
Senior Lien, Series D (TD Bank NA LOC),
0.28%, 5/06/11	$ 20,000	$ 20,000,000
Total Municipal Bonds — 7.5%		245,800,000
U.S. Government Sponsored Agency Obligations
Fannie Mae Discount Notes, 0.17%, 8/03/11 (d)	40,000	39,982,433
Fannie Mae Variable Rate Notes (b):
0.20%, 7/26/12	$35,500	$35,491,239
0.24%, 12/20/12	17,500	17,494,196
Federal Home Loan Bank Variable Rate Notes,
0.24%, 10/06/11 (b)	50,000	49,991,259
Freddie Mac Variable Rate Notes (b):
0.19%, 5/05/11	70,000	69,999,826
0.16%, 12/29/11	25,000	24,991,664
0.21%, 4/03/12	10,000	9,996,254
0.34%, 1/24/13	19,000	18,986,726
Total U.S. Government Sponsored Agency Obligations — 8.1%		266,933,597
U.S. Treasury Obligations
U.S. Treasury Bills (d):
0.19%, 5/26/11	17,700	17,697,758
0.22%, 6/02/11	37,000	36,993,245
0.23%, 6/30/11	39,000	38,985,619
0.20%, 7/07/11	39,500	39,485,517
0.23%, 10/31/11	33,000	33,125,529
U.S. Treasury Notes:
4.88%, 5/31/11	27,000	27,099,159
1.13%, 6/30/11	61,000	61,086,568
5.00%, 8/15/11	40,000	40,549,192
1.00%, 9/30/11	47,000	47,142,464
4.63%, 10/31/11	30,000	30,650,284
0.88%, 1/31/12	37,000	37,183,719
Total U.S. Treasury Obligations — 12.5%		409,999,054
Repurchase Agreements
Barclays Capital, Inc., 0.03%, 5/02/11 (Purchased on
4/29/11 to be repurchased at $80,000,200,
collateralized by U.S. Treasury Note, 0.75%, due
5/31/12, par and fair values of $80,945,200 and
$81,600,100, respectively)	80,000	80,000,000

See Notes to Financial Statements.

READY ASSETS PRIME MONEY FUND  APRIL 30, 2011  7 

Schedule of Investments (concluded)
(Percentages shown are based on Net Assets)

		Par
Repurchase Agreements (concluded)		(000)	Value
Deutsche Bank Securities, Inc., 0.03%, 5/02/11
(Purchased on 4/29/11 to be repurchased at
$71,206,178, collateralized by U.S. Treasury Note,
2.50%, due 6/30/17, par and fair values of
$71,815,200 and $72,630,176, respectively)	$ 71,206		$ 71,206,000
Total Repurchase Agreements — 4.6%			151,206,000
Total Investments (Cost — $3,283,685,111*) — 99.9%			3,283,685,111
Other Assets Less Liabilities — 0.1%			4,048,197
Net Assets — 100.0%			$3,287,733,308

* Cost for federal income tax purposes.
(a) Issuer is a US branch of a foreign domiciled bank.
(b) Variable rate security. Rate shown is as of report date.
(c) Variable rate security. Rate shown is as of report date and maturity shown is the
date the principal owed can be recovered through demand.
(d) Rates shown are discount rates or a range of discount rates paid at the time of
purchase.
(e) Security exempt from registration under Rule 144A of the Securities Act of 1933.
This security may be resold in transactions exempt from registration to qualified
institutional investors.

• Fair Value Measurements — Various inputs are used in determining the fair value
of investments. These inputs are summarized in three broad levels for financial
statement purposes as follows:
• Level 1 — price quotations in active markets/exchanges for identical assets
and liabilities
• Level 2 — other observable inputs (including, but not limited to: quoted prices
for similar assets or liabilities in markets that are active, quoted prices for iden-
tical or similar assets or liabilities in markets that are not active, inputs other
than quoted prices that are observable for the assets or liabilities (such as
interest rates, yield curves, volatilities, prepayment speeds, loss severities,
credit risks and default rates) or other market-corroborated inputs)
• Level 3 — unobservable inputs based on the best information available in the
circumstances, to the extent observable inputs are not available (including the
Fund's own assumptions used in determining the fair value of investments)

The inputs or methodologies used for valuing securities are not necessarily an
indication of the risk associated with investing in those securities. For information
about the Fund's policy regarding valuation of investments and other significant
accounting policies, please refer to Note 1 of the Notes to Financial Statements.

The following table summarizes the inputs used as of April 30, 2011 in
determining the fair valuation of the Fund's investments:

Valuation Inputs	Level 1	Level 2	Level 3	Total
Assets:
Investments:
Short-Term
Securities1	—	$3,283,685,111	—	$3,283,685,111

¹ See above Schedule of Investments for values in each security type.

See Notes to Financial Statements.

8  READY ASSETS PRIME MONEY FUND  APRIL 30, 2011 

Statement of Assets and Liabilities
April 30, 2011
Assets
Investments at value — unaffiliated (cost — $3,283,685,111)	$ 3,283,685,111
Cash	142
Receivable from custodian	33,851
Capital shares sold receivable	16,499,985
Interest receivable	2,810,199
Prepaid expenses	106,629
Total assets	3,303,135,917
Liabilities
Capital shares redeemed payable	14,349,626
Investment advisory fees payable	400,826
Other affiliates payable	21,700
Officer's and Trustees' fees payable	1,414
Other accrued expenses payable	629,043
Total liabilities	15,402,609
Net Assets	$ 3,287,733,308
Net Assets Consist of
Paid-in capital	$ 3,287,681,804
Undistributed net realized gain	51,504
Net Assets — $1.00 net asset value per share, 3,287,681,803 shares outstanding, unlimited number of shares authorized, $0.10 par value	$ 3,287,733,308

See Notes to Financial Statements.

READY ASSETS PRIME MONEY FUND  APRIL 30, 2011  9 

Statement of Operations
Year Ended April 30, 2011
Investment Income
Interest	$ 13,336,650
Expenses
Investment advisory	13,454,856
Transfer agent	5,474,073
Distribution fees	4,392,776
Accounting services	241,736
Registration	128,814
Professional	111,741
Printing	107,940
Officer and Trustees	87,665
Custodian	86,721
Miscellaneous	91,176
Total expenses	24,177,498
Less fees waived by advisor	(6,448,538)
Less distribution fees waived	(4,392,776)
Less fees paid indirectly	(177)
Total expenses after fees waived and paid indirectly	13,336,007
Net investment income	643
Realized Gain
Net realized gain from investments	72,482
Net Increase in Net Assets Resulting from Operations	$ 73,125

See Notes to Financial Statements.

10  READY ASSETS PRIME MONEY FUND  APRIL 30, 2011 

Statements of Changes in Net Assets
	Year Ended April 30,
Increase (Decrease) in Net Assets:	2011	2010
Operations
Net investment income	$ 643	$ 1,866,090
Net realized gain	72,482	159,810
Net increase in net assets resulting from operations	73,125	2,025,900
Dividends and Distributions to Shareholders From
Net investment income	(643)	(2,270,898)
Net realized gain	(285,001)	(21,987)
Decrease in net assets resulting from dividends and distributions to shareholders	(285,644)	(2,292,885)
Capital Share Transactions
Net proceeds from sale of shares	3,146,150,383	4,297,016,778
Reinvestment of dividends and distributions	276,964	2,291,010
Cost of shares redeemed	(3,792,886,091)	(5,273,690,492)
Net decrease in net assets derived from capital share transactions	(646,458,744)	(974,382,704)
Net Assets
Total decrease in net assets	(646,671,263)	(974,649,689)
Beginning of year	3,934,404,571	4,909,054,260
End of year	$3,287,733,308	$3,934,404,571

See Notes to Financial Statements.

READY ASSETS PRIME MONEY FUND  APRIL 30, 2011  11 

Financial Highlights
			Period
			January 1,
			2009	Year Ended December 31,
	Year Ended April 30,		to April 30,
	2011	2010	2009	2008	2007	2006
Per Share Operating Performance
Net asset value, beginning of period	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00
Net investment income	0.0000	0.0005	0.0019	0.0258	0.0470		0.0432
Net realized and unrealized gain (loss)	0.0001	—	—	0.0000	0.0001		(0.0006)
Net increase from investment operations	0.0001	0.0005	0.0019	0.0258	0.0471		0.0426
Dividends and distributions from:
Net investment income	(0.0000)	(0.0005)	(0.0019)	(0.0258)	(0.0470)		(0.0432)
Net realized gain	(0.0001)	—	—	—	—		(0.0000)
Total dividends and distributions	(0.0001)	(0.0005)	(0.0019)	(0.0258)	(0.0470)		(0.0432)
Net asset value, end of period	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00
Total Investment Return1
Total investment return	0.01%	0.05%	0.19%2	2.62%	4.81%		4.41%
Ratios to Average Net Assets
Total expenses	0.68%	0.68%	0.69%3	0.65%	0.65%		0.66%
Total expenses after fees waived and paid indirectly	0.37%	0.41%	0.69%3	0.65%	0.65%		0.66%
Net investment income	0.00%	0.04%	0.57%3	2.57%	4.70%		4.34%
Supplemental Data
Net assets, end of period (000)	$ 3,287,733	$3,934,405	$4,909,054	$5,054,948	$5,032,673	$4,392,407

¹ Where applicable, total investment returns include the reinvestment of dividends and distributions.
² Aggregate total investment return.
³ Annualized.

See Notes to Financial Statements.

12  READY ASSETS PRIME MONEY FUND  APRIL 30, 2011 

Notes to Financial Statements

1. Organization and Significant Accounting Policies:

Ready Assets Prime Money Fund (the “Fund”) is registered under the
Investment Company Act of 1940, as amended (the “1940 Act”), as a
diversified, open-end management investment company. The Fund is
organized as a Massachusetts business trust. The Fund's financial state-
ments are prepared in conformity with accounting principles generally
accepted in the United States of America ("US GAAP"), which may
require management to make estimates and assumptions that affect the
reported amounts and disclosures in the financial statements. Actual
results could differ from those estimates.

The following is a summary of significant accounting policies followed by
the Fund:

Valuation: The Fund's investments are valued under the amortized cost
method which approximates current market value in accordance with
Rule 2a-7 of the 1940 Act. Under this method, investments are valued
at cost when purchased and thereafter, a constant proportionate accre-
tion and amortization of any discounts and premiums are recorded until
the maturity of the security. The Fund seeks to maintain its net asset
value per share at $1.00, although there is no assurance that it will be
able to do so on a continuing basis.

Repurchase Agreements: The Fund may invest in repurchase agree-
ments. In a repurchase agreement, the Fund purchases a security from a
counterparty who agrees to repurchase the same security at a mutually
agreed upon date and price. On a daily basis, the counterparty is
required to maintain collateral subject to the agreement and in value
no less than the agreed repurchase amount. The agreements are condi-
tioned upon the collateral being deposited under the Federal Reserve
book entry system or held in a segregated account by the Fund's
custodian or designated sub-custodians under tri-party repurchase
agreements. In the event the counterparty defaults and the fair value
of the collateral declines, the Fund could experience losses, delays
and costs in liquidating the collateral.

Investment Transactions and Investment Income: For financial reporting
purposes, investment transactions are recorded on the dates the trans-
actions are entered into (the trade dates). Realized gains and losses on
investment transactions are determined on the identified cost basis.
Interest income, including amortization and accretion of premiums and
discounts on debt securities, is recognized on the accrual basis.

Dividends and Distributions: Dividends from net investment income
are declared daily and paid monthly. Distributions of capital gains are
recorded on the ex-dividend dates. The amount and timing of dividends
and distributions are determined in accordance with federal income tax
regulations, which may differ from US GAAP.

Income Taxes: It is the Fund's policy to comply with the requirements
of the Internal Revenue Code of 1986, as amended, applicable to regu-
lated investment companies and to distribute substantially all of its
taxable income to its shareholders. Therefore, no federal income tax
provision is required.

The Fund files US federal and various state and local tax returns. No
income tax returns are currently under examination. The statute of
limitations on the Fund's US federal tax returns remains open for the
two years ended April 30, 2011, the period ended April 30, 2009 and
the year ended December 31, 2008. The statutes of limitations on the
Fund's state and local tax returns may remain open for an additional
year depending upon the jurisdiction. Management does not believe
there are any uncertain tax positions that require recognition of a
tax liability.

Other: Expenses directly related to the Fund are charged to that Fund.
Other operating expenses shared by several funds are pro rated among
those funds on the basis of relative net assets or other appropriate
methods. The Fund has an arrangement with the custodian whereby fees
may be reduced by credits earned on uninvested cash balances, which
if applicable are shown as fees paid indirectly in the Statement of
Operations. The custodian imposes fees on overdrawn cash balances,
which can be offset by accumulated credits earned or may result in
additional custody charges.

2. Investment Advisory Agreement and Other Transactions
with Affiliates:

As of April 30, 2011, the PNC Financial Services Group, Inc. ("PNC"),
Bank of America Corporation ("BAC") and Barclays Bank PLC
("Barclays") were the largest stockholders of BlackRock, Inc.
("BlackRock"). Due to the ownership structure, PNC is an affiliate of
the Fund for 1940 Act purposes, but BAC and Barclays are not.

The Fund entered into an Investment Advisory Agreement with BlackRock
Advisors, LLC (the “Manager”), the Fund's investment advisor, an indirect,
wholly owned subsidiary of BlackRock, to provide investment advisory
and administration services. The Manager is responsible for the manage-
ment of the Fund's portfolio and provides the necessary personnel, facil-
ities, equipment and certain other services necessary to the operations
of the Fund. For such services, the Fund pays the Manager a monthly fee
at the following annual rates of the Fund's average daily net assets as
follows:

Portion of Average Daily Value of Net Assets:	Rate
Not exceeding $500 million	0.500%
In excess of $500 million but not exceeding $1 billion	0.400%
In excess of $1 billion but not exceeding $5 billion	0.350%
In excess of $5 billion but not exceeding $10 billion	0.325%
In excess of $10 billion but not exceeding $15 billion	0.300%
In excess of $15 billion but not exceeding $20 billion	0.275%
In excess of $20 billion	0.250%

READY ASSETS PRIME MONEY FUND  APRIL 30, 2011  13 

Notes to Financial Statements (concluded)

The Manager entered into a sub-advisory agreement with BlackRock
Institutional Management Corporation ("BIMC"), an affiliate of the
Manager. The Manager pays BIMC for services it provides, a monthly fee
that is a percentage of the investment advisory fees paid by the Fund to
the Manager.

For the year ended April 30, 2011, the Fund reimbursed the Manager
$67,453 for certain accounting services, which are included in account-
ing services in the Statement of Operations.

The Fund entered into a Distribution Agreement and Distribution Plan
with BlackRock Investments, LLC (”BRIL“), an affiliate of BlackRock.
Pursuant to the Distribution Plan and in accordance with Rule 12b-1
under the 1940 Act, the Fund pays BRIL ongoing distribution fees. The
fees are accrued daily and paid monthly at the annual rate of 0.125%
based upon the average daily net assets of the shares of the Fund.

The Manager and BRIL voluntarily agreed to waive management and
distribution fees and reimburse operating expenses to enable the Fund
to maintain a minimum daily net investment income dividend. These
amounts are reported in the Statement of Operations as fees waived
by advisor and distribution fees waived. The Manager and BRIL may
discontinue the waiver or reimbursement at any time.

Certain officers and/or trustees of the Fund are trustees and/or directors
of BlackRock or its affiliates. The Fund reimburses the Manager for com-
pensation paid to the Fund's Chief Compliance Officer.

3. Income Tax Information:

The tax character of distributions paid during the fiscal year ended
April 30, 2011 and April 30, 2010 was as follows:

Ordinary income:
4/30/2011	$ 285,644
4/30/2010	2,270,898
Long-term capital gains distributions:
4/30/2011	—
4/30/2010	$ 21,987
Total distributions:
4/30/2011	$ 285,644
4/30/2010	$ 2,292,885
As of April 30, 2011, the tax components of accumulated net earnings
were as follows:
Undistributed ordinary income	$ 51,504

4. Concentration, Market and Credit Risk:

In the normal course of business, the Fund invests in securities and
enters into transactions where risks exist due to fluctuations in the mar-
ket (market risk) or failure of the issuer of a security to meet all its obli-
gations (issuer credit risk). The value of securities held by the Fund may
decline in response to certain events, including those directly involving
the issuers whose securities are owned by the Fund; conditions affecting
the general economy; overall market changes; local, regional or global
political, social or economic instability; and currency and interest rate
and price fluctuations. Similar to issuer credit risk, the Fund may be
exposed to counterparty credit risk, or the risk that an entity with which
the Fund has unsettled or open transactions may fail to or be unable to
perform on its commitments. The Fund manages counterparty credit risk
by entering into transactions only with counterparties that it believes
have the financial resources to honor their obligations and by monitoring
the financial stability of those counterparties. Financial assets, which
potentially expose the Fund to market, issuer and counterparty credit
risks, consist principally of financial instruments and receivables due
from counterparties. The extent of the Fund's exposure to market, issuer
and counterparty credit risks with respect to these financial assets is
generally approximated by their value recorded in the Fund's Statement
of Assets and Liabilities, less any collateral held by the Fund.

5. Capital Share Transactions:

The number of shares sold, reinvested and redeemed corresponds to the
net proceeds from the sale of shares, reinvestment of dividends and dis-
tributions and cost of shares redeemed, respectively, since shares are
sold and redeemed at $1.00 per share.

6. Subsequent Events:

Management has evaluated the impact of all subsequent events on the
Fund through the date the financial statements were issued and has
determined that there were no subsequent events requiring adjustment
or additional disclosure in the financial statements.

14  READY ASSETS PRIME MONEY FUND  APRIL 30, 2011 

Report of Independent Registered Public Accounting Firm

To the Shareholders and Board of Trustees of
Ready Assets Prime Money Fund:

We have audited the accompanying statement of assets and liabilities of
Ready Assets Prime Money Fund (the “Fund”), including the schedule of
investments, as of April 30, 2011, and the related statement of opera-
tions for the year then ended, the statements of changes in net assets
for each of the two years in the period then ended, and the financial
highlights for each of the two years in the period then ended, the period
January 1, 2009 to April 30, 2009, and each of the three years in the
period ended December 31, 2008. These financial statements and
financial highlights are the responsibility of the Fund’s management.
Our responsibility is to express an opinion on these financial statements
and financial highlights based on our audits.

We conducted our audits in accordance with the standards of the Public
Company Accounting Oversight Board (United States). Those standards
require that we plan and perform the audit to obtain reasonable assur-
ance about whether the financial statements and financial highlights
are free of material misstatement. The Fund is not required to have, nor
were we engaged to perform, an audit of its internal control over finan-
cial reporting. Our audits included consideration of internal control over
financial reporting as a basis for designing audit procedures that are
appropriate in the circumstances, but not for the purpose of expressing
an opinion on the effectiveness of the Fund’s internal control over
financial reporting. Accordingly, we express no such opinion. An audit
also includes examining, on a test basis, evidence supporting the
amounts and disclosures in the financial statements, assessing the
accounting principles used and significant estimates made by manage-
ment, as well as evaluating the overall financial statement presentation.
Our procedures included confirmation of securities owned as of April 30,
2011, by correspondence with the custodian and brokers. We believe
that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements and financial highlights referred
to above present fairly, in all material respects, the financial position of
Ready Assets Prime Money Fund as of April 30, 2011, the results of its
operations for the year then ended, the changes in its net assets for
each of the two years in the period then ended, and the financial high-
lights for each of the two years in the period then ended, the period
January 1, 2009 to April 30, 2009, and each of the three years in the
period ended December 31, 2008, in conformity with accounting
principles generally accepted in the United States of America.

Deloitte & Touche LLP
Princeton, New Jersey
June 24, 2011

Important Tax Information (Unaudited)

The following information is provided with respect to the ordinary income distributions paid by the Fund for the taxable year ended April 30, 2011:

Federal Obligation Interest1
Months Paid: May 2010 – April 2011	0.03%
Interest-Related Dividends and Qualified Short-Term Capital Gains for Non-US Residents2
Months Paid: May 2010 – December 2010	100.00%
Months Paid: January 2011 – April 2011	99.99%

¹ The law varies in each state as to whether and what percentage of dividend income attributable to federal obligations is exempt from state income tax. We recommend that you
consult your tax advisor to determine if any portion of the dividends you received is exempt from state income taxes.
² Represents the portion of the taxable ordinary income dividends eligible for exemption from US withholding tax for nonresident aliens and foreign corporations.

READY ASSETS PRIME MONEY FUND  APRIL 30, 2011  15 

Officers and Trustees
				Number of BlackRock-
				Advised Registered
		Length		Investment Companies
	Position(s)	of Time		(“RICs”) Consisting of
Name, Address	Held with	Served as		Investment Portfolios	Public
and Year of Birth	Fund	a Trustee2	Principal Occupation(s) During Past Five Years	(“Portfolios”) Overseen	Directorships
Independent Trustees1
Ronald W. Forbes	Co-Chair of	Since	Professor Emeritus of Finance, School of Business, State University	36 RICs consisting of	None
55 East 52nd Street	the Board	2007	of New York at Albany since 2000.	98 Portfolios
New York, NY 10055	and Trustee
1940
Rodney D. Johnson	Co-Chair of	Since	President, Fairmount Capital Advisors, Inc. since 1987; Member	36 RICs consisting of	None
55 East 52nd Street	the Board	2007	of the Archdiocesan Investment Committee of the Archdiocese of	98 Portfolios
New York, NY 10055	and Trustee		Philadelphia since 2004; Director, The Committee of Seventy (civic)
1941			since 2006; Director, Fox Chase Cancer Center from 2004 to 2010.
David O. Beim	Trustee	Since	Professor of Professional Practice at the Columbia University	36 RICs consisting of	None
55 East 52nd Street		2007	Graduate School of Business since 1991; Trustee, Phillips Exeter	98 Portfolios
New York, NY 10055			Academy since 2002; Chairman, Wave Hill, Inc. (public garden and
1940			cultural center) from 1990 to 2006.
Dr. Matina S. Horner	Trustee	Since	Executive Vice President of Teachers Insurance and Annuity Associa-	36 RICs consisting of	NSTAR (electric
55 East 52nd Street		2007	tion and College Retirement Equities Fund from 1989 to 2003.	98 Portfolios	and gas utility)
New York, NY 10055
1939
Herbert I. London	Trustee	Since	Professor Emeritus, New York University since 2005; John M. Olin	36 RICs consisting of	AIMS Worldwide,
55 East 52nd Street		2007	Professor of Humanities, New York University from 1993 to 2005	98 Portfolios	Inc. (marketing)
New York, NY 10055			and Professor thereof from 1980 to 2005; President, Hudson
1939			Institute (policy research organization) since 1997 and Trustee
			thereof since 1980; Chairman of the Board of Trustees for Grantham
			University since 2006; Director, InnoCentive, Inc. (strategic solutions
			company) since 2005; Director, Cerego, LLC (software development
			and design) since 2005; Director, Cybersettle (dispute resolution
			technology) since 2009.
Cynthia A. Montgomery	Trustee	Since	Professor, Harvard Business School since 1989; Director, McLean	36 RICs consisting of	Newell Rubbermaid,
55 East 52nd Street		2007	Hospital since 2005; Director, Harvard Business School Publishing	98 Portfolios	Inc. (manufacturing)
New York, NY 10055			from 2005 to 2010.
1952
Joseph P. Platt	Trustee	Since	Director, The West Penn Allegheny Health System (a not-for-profit	36 RICs consisting of	Greenlight Capital
55 East 52nd Street		2007	health system) since 2008; Director, Jones and Brown (Canadian	98 Portfolios	Re, Ltd (reinsurance
New York, NY 10055			insurance broker) since 1998; General Partner, Thorn Partners, LP		company)
1947			(private investment) since 1998; Director, WQED Multi-Media (public
			broadcasting not-for-profit) since 2001; Partner, Amarna Corporation,
			LLC (private investment company) from 2002 to 2008.
Robert C. Robb, Jr.	Trustee	Since	Partner, Lewis, Eckert, Robb and Company (management and	36 RICs consisting of	None
55 East 52nd Street		2007	financial consulting firm) since 1981.	98 Portfolios
New York, NY 10055
1945
Toby Rosenblatt	Trustee	Since	President, Founders Investments Ltd. (private investments)	36 RICs consisting of	None
55 East 52nd Street		2007	since 1999; Director, College Access Foundation of California	98 Portfolios
New York, NY 10055			(philanthropic foundation) since 2009; Director, Forward
1938			Management, LLC since 2007; Director, A.P. Pharma, Inc.
			(pharmaceuticals) from 1983 to 2011; Director, The James Irvine
Foundation (philanthropic foundation) from 1998 to 2008.

16  READY ASSETS PRIME MONEY FUND  APRIL 30, 2011 

Officers and Trustees (continued)
				Number of BlackRock-
				Advised Registered
		Length		Investment Companies
	Position(s)	of Time		(“RICs”) Consisting of
Name, Address	Held with	Served as		Investment Portfolios	Public
and Year of Birth	Fund	a Trustee2	Principal Occupation(s) During Past Five Years	(“Portfolios”) Overseen	Directorships
Independent Trustees1 (concluded)
Kenneth L. Urish	Trustee	Since	Managing Partner, Urish Popeck & Co., LLC (certified public	36 RICs consisting of	None
55 East 52nd Street		2007	accountants and consultants) since 1976; Chairman Elect of	98 Portfolios
New York, NY 10055			the Professional Ethics Committee of the Pennsylvania Institute
1951			of Certified Public Accountants and Committee Member thereof
			since 2007; Member of External Advisory Board, The Pennsylvania
			State University Accounting Department since 2001; Trustee, The
			Holy Family Foundation from 2001 to 2010; President and Trustee,
Pittsburgh Catholic Publishing Associates from 2003 to 2008;
			Director, Inter-Tel from 2006 to 2007.
Frederick W. Winter	Trustee	Since	Professor and Dean Emeritus of the Joseph M. Katz School of	36 RICs consisting of	None
55 East 52nd Street		2007	Business, University of Pittsburgh since 2005 and Dean thereof	98 Portfolios
New York, NY 10055			from 1997 to 2005; Director, Alkon Corporation (pneumatics)
1945			since 1992; Director, Tippman Sports (recreation) since 2005;
			Director, Indotronix International (IT services) from 2004 to 2008.
	1 Trustees serve until their resignation, removal or death, or until December 31 of the year in which they turn 72. The Board has approved one-year
	extensions in terms of Trustees who turn 72 prior to December 31, 2013.
	2 Date shown is the earliest date a person has served as a Trustee for the Fund covered by this annual report. Following the combination of Merrill Lynch
	Investment Managers, L.P. (“MLIM”) and BlackRock in September 2006, the various legacy MLIM and legacy BlackRock fund boards were realigned and
	consolidated into three new fund boards in 2007. As a result, although the chart shows certain Trustees as joining the Fund’s board in 2007, each
	Trustee first became a member of the board of other legacy MLIM or legacy BlackRock funds as follows: David O. Beim, 1998; Ronald W. Forbes, 1977;
	Dr. Matina S. Horner, 2004; Rodney D. Johnson, 1995; Herbert I. London, 1987; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Robert C. Robb,
	Jr., 1998; Toby Rosenblatt, 2005; Kenneth L. Urish, 1999; and Frederick W. Winter, 1999.
Interested Trustees3
Richard S. Davis	Trustee	Since	Managing Director, BlackRock, Inc. since 2005; Chief Executive	165 RICs consisting of	None
55 East 52nd Street		2007	Officer, State Street Research & Management Company from 2000	290 Portfolios
New York, NY 10055			to 2005; Chairman of the Board of Trustees, State Street Research
1945			Mutual Funds from 2000 to 2005.
Henry Gabbay	Trustee	Since	Consultant, BlackRock, Inc. from 2007 to 2008; Managing Director,	165 RICs consisting of	None
55 East 52nd Street		2007	BlackRock, Inc. from 1989 to 2007; Chief Administrative Officer,	290 Portfolios
New York, NY 10055			BlackRock Advisors, LLC from 1998 to 2007; President of BlackRock
1947			Funds and BlackRock Bond Allocation Target Shares from 2005 to
			2007 and Treasurer of certain closed-end funds in the BlackRock
			fund complex from 1989 to 2006.
	3 Mr. Davis is an “interested person” as defined in the 1940 Act, of the Fund based on his position with BlackRock, Inc. and its affiliates. Mr. Gabbay is
	an “interested person” of the Fund based on his former positions with BlackRock, Inc. and its affiliates as well as his ownership of BlackRock, Inc. and
	The PNC Financial Services Group, Inc. securities. Trustees serve until their resignation, removal or death, or until December 31 of the year in which they
	turn 72. The Board has approved one-year extensions in terms of Trustees who turn 72 prior to December 31, 2013.

READY ASSETS PRIME MONEY FUND  APRIL 30, 2011  17 

Officers and Trustees (concluded)
	Position(s)
Name, Address	Held with	Length of
and Year of Birth	Fund	Time Served	Principal Occupation(s) During Past Five Years
Officers1
John M. Perlowski	President	Since	Managing Director of BlackRock, Inc. since 2009; Global Head of BlackRock Fund Administration since 2009;
55 East 52nd Street	and Chief	2010	Managing Director and Chief Operating Officer of the Global Product Group at Goldman Sachs Asset Management,
New York, NY 10055	Executive		L.P. from 2003 to 2009; Treasurer of Goldman Sachs Mutual Funds from 2003 to 2009 and Senior Vice President
1964	Officer		thereof from 2007 to 2009; Director of Goldman Sachs Offshore Funds from 2002 to 2009; Director of Family
			Resource Network (charitable foundation) since 2009.
Richard Hoerner, CFA	Vice	Since	Managing Director of BlackRock, Inc. since 2000; Co-head of BlackRock’s Cash Management Portfolio Management
55 East 52nd Street	President	2009	Group since 2002; Member of the Cash Management Group Executive Committee since 2005.
New York, NY 10055
1958
Brendan Kyne	Vice	Since	Managing Director of BlackRock, Inc. since 2010; Director of BlackRock, Inc. from 2008 to 2009; Head of Product
55 East 52nd Street	President	2009	Development and Management for BlackRock’s U.S. Retail Group since 2009, Co-head thereof from 2007 to
New York, NY 10055			2009; Vice President of BlackRock, Inc. from 2005 to 2008.
1977
Simon Mendelson	Vice	Since	Managing Director of BlackRock, Inc. since 2005; Co-head of the Global Cash and Securities Lending Group since
55 East 52nd Street	President	2009	2010; Chief Operating Officer and Head of the Global Client Group for BlackRock's Global Cash Management
New York, NY 10055			Business from 2007 to 2010; Head of BlackRock's Strategy and Development Group from 2005 to 2007; Partner
1964			of McKinsey & Co. from 1997 to 2005.
Brian Schmidt	Vice	Since	Managing Director of BlackRock, Inc. since 2004; Various positions with U.S. Trust Company from 1991 to 2003
55 East 52nd Street	President	2009	including Director from 2001 to 2003 and Senior Vice President from 1998 to 2003; Vice President, Chief Financial
New York, NY 10055			Officer and Treasurer of Excelsior Funds, Inc., Excelsior Tax-Exempt Funds, Inc. and Excelsior Funds Trust from 2001
1958			to 2003.
Christopher Stavrakos, CFA Vice		Since	Managing Director of BlackRock, Inc. since 2006; Co-head of BlackRock’s Cash Management Portfolio
55 East 52nd Street	President	2009	Management Group since 2006; Senior Vice President, CIO, and Director of Liability Management for the
New York, NY 10055			Securities Lending Group at Mellon Bank from 1999 to 2006.
1959
Neal Andrews	Chief	Since	Managing Director of BlackRock, Inc. since 2006; Senior Vice President and Line of Business Head of Fund
55 East 52nd Street	Financial	2007	Accounting and Administration at PNC Global Investment Servicing (U.S.) Inc. from 1992 to 2006.
New York, NY 10055	Officer
1966
Jay Fife	Treasurer	Since	Managing Director of BlackRock, Inc. since 2007 and Director in 2006; Assistant Treasurer of the MLIM and Fund
55 East 52nd Street		2007	Asset Management, L.P. advised funds from 2005 to 2006; Director of MLIM Fund Services Group from 2001
New York, NY 10055			to 2006.
1970
Brian Kindelan	Chief	Since	Chief Compliance Officer of the BlackRock-advised funds since 2007; Managing Director and Senior Counsel of
55 East 52nd Street	Compliance	2007	BlackRock, Inc. since 2005.
New York, NY 10055	Officer
1959
Ira P. Shapiro	Secretary	Since	Managing Director of BlackRock, Inc. since 2009; Managing Director and Associate General Counsel of Barclays
55 East 52nd Street		2010	Global Investors from 2008 to 2009; Principal thereof from 2004 to 2008.
New York, NY 10055
1963
	1 Officers of the Fund serve at the pleasure of the Board.
	Further information about the Officers and Trustees is available in the Fund’s Statement of Additional Information, which can be obtained without
	charge by calling (800) 441-7762.

Investment Advisor	Custodian	Accounting Agent	Distributor	Address of the Fund
BlackRock Advisors, LLC	The Bank of	State Street Bank	BlackRock Investments, LLC 100 Bellevue Parkway
Wilmington, DE 19809	New York Mellon	and Trust Company	New York, NY 10022	Wilmington, DE 19809
	New York, NY 10286	Princeton, NJ 08540
Sub-Advisor	Transfer Agent	Independent Registered	Legal Counsel
BlackRock Institutional	Financial Data	Public Accounting Firm	Sidley Austin LLP	Effective November 16,
Management Corporation	Services, Inc.	Deloitte & Touche LLP	New York, NY 10019	2010, Ira P. Shapiro became
Wilmington, DE 19809	Jacksonville, FL 32246	Princeton, NJ 08540		Secretary of the Trust.

18  READY ASSETS PRIME MONEY FUND  APRIL 30, 2011 

Additional Information

General Information

Electronic Delivery

Electronic copies of most financial reports and prospectuses are avail-
able on the Fund’s website (http://www.blackrock.com/moneymarketre-
ports) or shareholders can sign up for e-mail notifications of quarterly
statements, annual and semi-annual reports and prospectuses by
enrolling in the Fund’s electronic delivery program.

Shareholders Who Hold Accounts with Investment Advisors, Banks or
Brokerages:

Please contact your financial advisor to enroll. Please note that not all
investment advisors, banks or brokerages may offer this service.

Householding

The Fund will mail only one copy of shareholder documents, including
prospectuses, annual and semi-annual reports and proxy statements, to
shareholders with multiple accounts at the same address. This practice
is commonly called “householding” and is intended to reduce expenses
and eliminate duplicate mailings of shareholder documents. Mailings of
your shareholder documents may be householded indefinitely unless you
instruct us otherwise. If you do not want the mailing of these documents
to be combined with those for other members of your household, please
contact the Transfer Agent at (800) 221-7210.

Availability of Quarterly Schedule of Investments

The Fund files its complete schedule of portfolio holdings with the
Securities and Exchange Commission (the “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 http://www.sec.gov and may also be
reviewed and copied at the SEC’s Public Reference Room in Washington,
D.C. Information on how to access documents on the SEC’s website
without charge may be obtained by calling (800) SEC-0330. The Fund’s
Forms N-Q may also be obtained upon request and without charge by
calling (800) 626 1960.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the Fund uses to
determine how to vote proxies relating to portfolio securities is available
(1) without charge, upon request, by calling (800) 626-1960; (2) at
http://www.blackrock.com; and (3) on the SEC’s website at
http://www.sec.gov.

Availability of Proxy Voting Record

Information about how the Fund voted proxies relating to securities
held in the Fund’s portfolio during the most recent 12-month period
ended June 30 is available upon request and without charge (1) at
http://www.blackrock.com or by calling (800) 626-1960 and (2) on
the SEC’s website at http://www.sec.gov.

BlackRock Privacy Principles

BlackRock is committed to maintaining the privacy of its current and for-
mer fund investors and individual clients (collectively, “Clients”) and to
safeguarding their non-public personal information. The following infor-
mation is provided to help you understand what personal information
BlackRock collects, how we protect that information and why in certain
cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations
require BlackRock to provide you with additional or different privacy-
related rights beyond what is set forth below, then BlackRock will comply
with those specific laws, rules or regulations.

BlackRock obtains or verifies personal non-public information from and
about you from different sources, including the following: (i) information
we receive from you or, if applicable, your financial intermediary, on appli-
cations, forms or other documents; (ii) information about your transac-
tions with us, our affiliates, or others; (iii) information we receive from a
consumer reporting agency; and (iv) from visits to our websites.

BlackRock does not sell or disclose to non-affiliated third parties any
non-public personal information about its Clients, except as permitted by
law or as is necessary to respond to regulatory requests or to service
Client accounts. These non-affiliated third parties are required to protect
the confidentiality and security of this information and to use it only for
its intended purpose.

We may share information with our affiliates to service your account
or to provide you with information about other BlackRock products or
services that may be of interest to you. In addition, BlackRock restricts
access to non-public personal information about its Clients to those
BlackRock employees with a legitimate business need for the informa-
tion. BlackRock maintains physical, electronic and procedural safeguards
that are designed to protect the non-public personal information of its
Clients, including procedures relating to the proper storage and disposal
of such information.

READY ASSETS PRIME MONEY FUND  APRIL 30, 2011  19 

This report is transmitted to shareholders only. It is not

authorized for use as an offer of sale or solicitation of an

offer to buy shares of the Fund unless accompanied or

preceded by the Fund’s current prospectus. An investment

in the Fund is not insured or guaranteed by the Federal

Deposit Insurance Corporation or any other government

agency. Although the Fund seeks to preserve the value of

your investment at $1.00 per share, it is possible to lose

money by investing in the Fund. Total return information

assumes reinvestment of all distributions. Past performance

results shown in this report should not be considered a rep-

resentation of future performance. For current month-end

performance information, call (800) 626-1960. The Fund’s

current 7-day yield more closely reflects the current earn-

ings of the Fund than the total returns quoted. Statements

and other information herein are as dated and are subject

to change.

Item 2 – Code of Ethics – The registrant (or the “Fund”) has adopted a code of ethics, as of the end
of the period covered by this report, applicable to the registrant’s principal executive officer,
principal financial officer, principal accounting officer, or controller, or persons performing
similar functions. During the period covered by this report, there have been no amendments
to or waivers granted under the code of ethics. A copy of the code of ethics is available
without charge at www.blackrock.com.

Item 3 – Audit Committee Financial Expert – The registrant’s board of directors (the “board of
directors”), has determined that (i) the registrant has the following audit committee financial
expert serving on its audit committee and (ii) each audit committee financial expert is
independent:
Kenneth L. Urish

Under applicable securities laws, a person determined to be an audit committee financial
expert will not be deemed an “expert” for any purpose, including without limitation for the
purposes of Section 11 of the Securities Act of 1933, as a result of being designated or
identified as an audit committee financial expert. The designation or identification of a
person as an audit committee financial expert does not impose on such person any duties,
obligations, or liabilities greater than the duties, obligations, and liabilities imposed on such
person as a member of the audit committee and board of directors in the absence of such
designation or identification.

Item 4 – Principal Accountant Fees and Services

The following table presents fees billed by Deloitte & Touche LLP (“D&T”) in each of the
last two fiscal years for the services rendered to the Fund:

	(a) Audit Fees		(b) Audit-Related Fees1		(c) Tax Fees2		(d) All Other Fees3
	Current	Previous	Current	Previous	Current	Previous	Current	Previous
	Fiscal Year	Fiscal Year	Fiscal Year	Fiscal Year	Fiscal Year	Fiscal Year	Fiscal Year	Fiscal  Year
Entity Name	End	End	End	End	End	End	End	End
Ready Assets Prime
Money Fund	$26,000	$25,000	$0	$0	$9,100	$6,100	$0	$1,464

The following table presents fees billed by D&T that were required to be approved by the
registrant’s audit committee (the “Committee”) for services that relate directly to the
operations or financial reporting of the Fund and that are rendered on behalf of BlackRock
Advisors, LLC (“Investment Adviser”) and entities controlling, controlled by, or under
common control with BlackRock (not including any sub-adviser whose role is primarily
portfolio management and is subcontracted with or overseen by another investment adviser)
that provide ongoing services to the Fund (“Fund Service Providers”):

	Current Fiscal Year End	Previous Fiscal Year End
(b) Audit-Related Fees1	$0	$0
(c) Tax Fees2	$0	$0
(d) All Other Fees3	$3,030,000	$2,950,000
1 The nature of the services include assurance and related services reasonably related to the performance of the audit of financial statements
not included in Audit Fees.
2 The nature of the services include tax compliance, tax advice and tax planning.
3 The nature of the services include a review of compliance procedures and attestation thereto.

(e)(1) Audit Committee Pre-Approval Policies and Procedures:

The Committee has adopted policies and procedures with regard to the pre-approval
of services. Audit, audit-related and tax compliance services provided to the registrant on
an annual basis require specific pre-approval by the Committee. The Committee also must
approve other non-audit services provided to the registrant and those non-audit services
provided to the Investment Adviser and Fund Service Providers that relate directly to the
operations and the financial reporting of the registrant. Certain of these non-audit services
that the Committee believes are a) consistent with the SEC’s auditor independence rules and
b) routine and recurring services that will not impair the independence of the independent
accountants may be approved by the Committee without consideration on a specific case-
by-case basis (“general pre-approval”). The term of any general pre-approval is 12 months
from the date of the pre-approval, unless the Committee provides for a different period. Tax
or other non-audit services provided to the registrant which have a direct impact on the
operations or financial reporting of the registrant will only be deemed pre-approved
provided that any individual project does not exceed $10,000 attributable to the registrant or
$50,000 per project. For this purpose, multiple projects will be aggregated to determine if
they exceed the previously mentioned cost levels.

Any proposed services exceeding the pre-approved cost levels will require specific
pre-approval by the Committee, as will any other services not subject to general pre-
approval (e.g., unanticipated but permissible services). The Committee is informed of each
service approved subject to general pre-approval at the next regularly scheduled in-person
board meeting. At this meeting, an analysis of such services is presented to the Committee
for ratification. The Committee may delegate to the Committee Chairman the authority to
approve the provision of and fees for any specific engagement of permitted non-audit
services, including services exceeding pre-approved cost levels.

(e)(2) None of the services described in each of Items 4(b) through (d) were approved by
the Committee pursuant to the de minimis exception in paragraph (c)(7)(i)(C) of Rule 2-01
of Regulation S-X.

(f) Not Applicable

(g) The aggregate non-audit fees paid to the accountant for services rendered by the
accountant to the registrant, the Investment Adviser and the Fund Service Providers were:

	Current Fiscal Year	Previous Fiscal Year
Entity Name	End	End
Ready Assets Prime Money	$9,100	$18,341
Fund

Additionally, SAS No. 70 fees for the current and previous fiscal years of $3,030,000 and
$2,950,000, respectively, were billed by D&T to the Investment Adviser.

(h) The Committee has considered and determined that the provision of non-audit services
that were rendered to the Investment Adviser (not including any non-affiliated sub-adviser
whose role is primarily portfolio management and is subcontracted with or overseen by the
registrant’s investment adviser), and the Fund Service Providers that were not pre-approved
pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with
maintaining the principal accountant’s independence.

Item 5 – Audit Committee of Listed Registrants – Not Applicable

Item 6 – Investments
(a) The registrant’s Schedule of Investments is included as part of the Report to
Stockholders filed under Item 1 of this Form.
(b) Not Applicable due to no such divestments during the semi-annual period covered since
the previous Form N-CSR filing.

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 – There have been no material
changes to these procedures.

Item 11 – Controls and Procedures

11(a) – The registrant’s principal executive and principal financial officers, or persons performing
similar functions, have concluded that the registrant’s disclosure controls and procedures (as
defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the
“1940 Act”)) are effective as of a date within 90 days of the filing of this report based on the
evaluation of these controls and procedures required by Rule 30a-3(b) under the 1940 Act
and Rule 15d-15(b) under the Securities Exchange Act of 1934, as amended.

11(b) – There were no changes in the registrant’s internal control over financial reporting (as
defined in Rule 30a-3(d) under the 1940 Act) 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 attached hereto

12(a)(1) – Code of Ethics – See Item 2

12(a)(2) – Certifications – Attached hereto

12(a)(3) – Not Applicable

12(b) – Certifications – Attached hereto

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.

Ready Assets Prime Money Fund

By: /S/ John M. Perlowski
John M. Perlowski
Chief Executive Officer (principal executive officer) of
Ready Assets Prime Money Fund

Date: July 6, 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/ John M. Perlowski
John M. Perlowski
Chief Executive Officer (principal executive officer) of
Ready Assets Prime Money Fund

Date: July 6, 2011

By: /S/ Neal J. Andrews
Neal J. Andrews
Chief Financial Officer (principal financial officer) of
Ready Assets Prime Money Fund

Date: July 6, 2011