November 2008 N-CSRS -- Converted by SEC Publisher, created by BCL Technologies Inc., for SEC Filing

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM N-CSRS

CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT
INVESTMENT COMPANIES

Investment Company Act file number 811-07642

Name of Fund: BlackRock MuniAssets Fund, Inc. (MUA)

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: Donald C. Burke, Chief Executive Officer, BlackRock
MuniAssets Fund, Inc., 800 Scudders Mill Road, Plainsboro, NJ, 08536. Mailing address:
P.O. Box 9011, Princeton, NJ, 08543-9011

Registrant’s telephone number, including area code: (800) 882-0052, Option 4

Date of fiscal year end: 05/31/2009

Date of reporting period: 06/01/2008 – 11/30/2008

Item 1 – Report to Stockholders


EQUITIES FIXED INCOME REAL ESTATE LIQUIDITY ALTERNATIVES BLACKROCK SOLUTIONS

Semi-Annual Report

NOVEMBER 30, 2008 | (UNAUDITED)

BlackRock MuniAssets Fund, Inc. (MUA)

BlackRock Muni Intermediate Duration Fund, Inc. (MUI)


NOT FDIC INSURED
MAY LOSE VALUE
NO BANK GUARANTEE


Table of Contents     
    Page 
 
A Letter to Shareholders    3 
Semi-Annual Report:     
Fund Summaries    4 
The Benefits and Risks of Leveraging    6 
Derivative Instruments    6 
Financial Statements:     
     Schedules of Investments    7 
     Statements of Assets and Liabilities    18 
     Statements of Operations    19 
     Statements of Changes in Net Assets    20 
Financial Highlights    21 
Notes to Financial Statements    23 
Officers and Directors    28 
Additional Information    29 

2 SEMI-ANNUAL REPORT

NOVEMBER 30, 2008


A Letter to Shareholders

Dear Shareholder

The present times may well be remembered as one of the most tumultuous periods in financial market history. Over the past year, the bursting of the

housing bubble and the resultant credit crisis mushroomed into an all-out global financial market meltdown, featuring the collapse of storied financial

firms, volatile swings in the world’s financial markets and monumental government responses designed to rescue the beleaguered financial system.

The U.S. economy appeared relatively resilient through the first half of 2008, when rising food and energy prices stoked fears of inflation. The tenor

changed dramatically in the second half, as inflation pressures subsided amid plummeting oil prices, but a uniform and rapid deterioration in key eco-

nomic indicators darkened growth prospects. Just after the close of the reporting period, the National Bureau of Economic Research officially declared

that the U.S. was in a recession, and that it had begun in December 2007. The Federal Reserve Board (the “Fed”), after slashing interest rates aggres-

sively in the early months of the year, resumed that rate-cutting campaign in the fall, bringing the target federal funds rate to a record low range of

between zero to 0.25% on December 16. More significant was the central bank’s pledge that future policy moves to revive the global economy and

financial markets would comprise primarily nontraditional and quantitative easing measures, such as capital injections, lending programs and govern-

ment guarantees.

Against this backdrop, U.S. equity markets experienced intense volatility, with periods of downward pressure punctuated by sharp rebounds. Losses were

significant and broad-based, though non-U.S. markets decelerated at a considerably faster pace than domestic equities — a stark reversal of prior years’

trends, when international stocks generally outpaced U.S. stocks.

Treasury issues also traded in a volatile fashion, but rallied overall (yields fell and prices correspondingly rose) and outperformed other fixed income

assets as investors retreated to the safest and most liquid investments. Amid spillover from historic events in the financial sector, municipals contended

with fewer market participants, lack of liquidity, a challenging funding environment and a backlog of new-issue supply, all of which contributed to the

sector’s underperformance relative to its taxable counterparts. Similarly, economic turmoil and badly broken credit markets plagued the high yield sec-

tor, with the third quarter of 2008 marking one of the worst periods in history for the asset class.

In all, an investor flight to safety prevailed, as evidenced in the six- and 12-month returns of the major benchmark indexes:     
Total Returns as of November 30, 2008    6-month    12-month 
U.S. equities (S&P 500 Index)    (35.20)%    (38.09)% 
Small cap U.S. equities (Russell 2000 Index)    (36.26)    (37.46) 
International equities (MSCI Europe, Australasia, Far East Index)    (44.92)    (47.79) 
U.S. Treasury securities (Merrill Lynch 10-Year U.S. Treasury Index)    11.62    12.69 
Taxable fixed income (Barclays Capital U.S. Aggregate Index*)    0.24    1.74 
Tax-exempt fixed income (Barclays Capital Municipal Bond Index*)    (4.98)    (3.61) 
High yield bonds         
(Barclays Capital U.S. Corporate High Yield 2% Issuer Capped Index*)    (31.73)    (30.49) 

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

Through periods of market turbulence, as ever, BlackRock’s full resources are dedicated to the management of our clients’ assets. For our most current

views on the economy and financial markets, we invite you to visit www.blackrock.com/funds. As always, we thank you for entrusting BlackRock with

your investments, and we look forward to continuing to serve you in the months and years ahead.


THIS PAGE NOT PART OF YOUR FUND REPORT

3


Fund Summary as of November 30, 2008

BlackRock MuniAssets Fund, Inc.

Investment Objective

BlackRock MuniAsset Fund, Inc. (MUA) (the “Fund”) seeks to provide shareholders with current income exempt from federal income taxes by invest-
ing primarily in a portfolio of medium-to-lower grade or unrated municipal obligations, the interest on which, in the opinion of bond counsel to the
issuer, is exempt from federal income taxes.

Performance

For the six months ended November 30, 2008, the Fund returned (24.60)% based on market price and (15.86)% based on net asset value (“NAV”).
For the same period, the closed-end Lipper High Yield Municipal Debt Funds category posted an average return of (21.97)% on a NAV basis. All returns
reflect reinvestment of dividends. The Fund moved from a premium to NAV to a discount by period-end, which accounts for the difference between per-
formance based on price and performance based on NAV. Factors that contributed to the Fund’s outperformance included a bias towards higher-quality
issues, a below-market duration position and an above-average distribution yield. Given improving value in the high yield municipal arena, activity during
the latter part of the reporting period was geared toward adopting a more neutral posture with respect to both credit and duration.


The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions.
These views are not intended to be a forecast of future events and are no guarantee of future results.

Fund Information                         

 
 
 
 
 
 
    Symbol on New York Stock Exchange                    MUA 
    Initial Offering Date                June 25, 1993 
    Yield on Closing Market Price as of November 30, 2008 ($9.71)1                8.34% 
    Tax Equivalent Yield2                    12.83% 
    Current Monthly Distribution per Common Share3                    $0.0675 
    Current Annualized Distribution per Common Share3                    $0.8100 
    Leverage as of November 30, 20084                    2% 
   
 
 
 
 
 
       1 Yield on closing market price is calculated by dividing the current annualized distribution per share by the closing market price. 
           Past performance does not guarantee future results.                     
       2 Tax equivalent yield assumes the maximum federal tax rate of 35%.                 
       3 The distribution is not constant and is subject to change.                     
       4 As a percentage of total managed assets, which is the total assets of the Fund (including any assets attributable to tender option bond 
           trusts (“TOBs”) minus the sum of accrued liabilities.                     
The table below summarizes the changes in the Fund’s market price and net asset value per share:

        11/30/08    5/31/08    Change    High    Low 
    Market Price    $ 9.71    $13.35    (27.27)%    $13.55         $ 7.28 
    Net Asset Value    $10.38    $12.79    (18.84)%    $12.84         $10.37 

The following charts show the portfolio composition and credit quality allocations of the Fund’s long-term investments:

     Portfolio Composition         
Sector    11/30/08    5/31/08 
Industrial & Pollution Control    26%    25% 
Hospital    23    27 
City, County and State    15    13 
Transportation    12    8 
Tax Revenue    7    7 
Power    6    7 
Housing    4    5 
Education    4    4 
Tobacco    2    3 
Water & Sewer    1    1 

     Credit Quality Allocations5         
Credit Rating    11/30/08    5/31/08 
AAA/Aaa    9%    12% 
AA/Aa    2    4 
A/A    13    7 
BBB/Baa    19    15 
BB/BA    11    10 
B/B    3    5 
CCC/Caa    4    4 
CC/Ca    1     
Not Rated6    38    43 

5 Using the higher of Standard & Poor’s (“S&P’s”) or Moody’s
Investors Service (“Moody’s”) ratings.
6 The investment advisor has deemed certain of these non-rated
securities to be of investment grade quality. As of November 30,
2008 and May 31, 2008, the market value of these securities
was $12,502,840 representing 6% and $12,388,252 represent-
ing 5%, respectively, of the Fund’s long-term investments.

4 SEMI-ANNUAL REPORT NOVEMBER 30, 2008


Fund Summary as of November 30, 2008 BlackRock Muni Intermediate Duration Fund, Inc.

Investment Objective

BlackRock Muni Intermediate Duration Fund, Inc. (MUI) (the “Fund”) seeks to provide shareholders with high current income exempt from federal
income taxes by investing primarily in a portfolio of municipal obligations, the interest on which, in the opinion of bond counsel to the issuer, is
exempt from federal income taxes.

Performance

For the six months ended November 30, 2008, the Fund returned (24.88)% based on market price and (12.59)% based on NAV. For the same period,
the closed-end Lipper Intermediate Municipal Debt Funds category posted an average return of (10.55)% on a NAV basis. All returns reflect reinvest-
ment of dividends. The Fund’s discount to NAV, which widened during the period, accounts for the difference between performance based on price and
performance based on NAV. The Fund’s lower-rated holdings were the primary source of underperformance, as these issues struggled amid a backdrop
of widening credit spreads and scarce liquidity. Benefiting performance were an overweight in pre-refunded bonds, a greater-than-average distribution
rate and a largely neutral duration positioning during a period of extreme volatility. Overall, portfolio turnover was low as reduced new-issue supply
coupled with the depressed valuations of existing holdings limited opportunities to restructure. Going forward, we will look for opportunities to increase
Fund exposure to higher-quality and more retail-oriented bonds, with a focus on more value-added trading. The Fund maintains a neutral to slightly
long duration bias.
The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions.
These views are not intended to be a forecast of future events and are no guarantee of future results.

Fund Information

Symbol on New York Stock Exchange    MUI 
Initial Offering Date    August 1, 2003 
Yield on Closing Market Price as of November 30, 2008 ($9.99)1    6.97% 
Tax Equivalent Yield2    10.72% 
Current Monthly Distribution per Common Share3    $0.058 
Current Annualized Distribution per Common Share3    $0.696 
Leverage as of November 30, 20084    42% 

1 Yield on closing market price is calculated by dividing the current annualized distribution per share by the closing market price.
Past performance does not guarantee future results.
2 Tax equivalent yield assumes the maximum federal tax rate of 35%.
3 The distribution rate is not constant and is subject to change.
4 As a percentage of total managed assets, which is the total assets of the Fund (including any assets attributable to Auction Market Preferred
Shares (“Preferred Shares”) and TOBs) minus the sum of accrued liabilities.

The table below summarizes the changes in the Fund’s market price and net asset value per share:         
    11/30/08    5/31/08    Change    High    Low 
Market Price    $ 9.99    $13.70    (27.08)%    $13.78    $ 7.82 
Net Asset Value    $12.26    $14.45    (15.16)%    $14.51    $11.68 

 
 
 
 
 
The following charts show the portfolio composition and credit quality allocations of the Fund’s long-term investments: 

     Portfolio Composition         
Sector    11/30/08    5/31/08 
Industrial & Pollution Control    15%    16% 
City/County/State    14    16 
Transportation    14    14 
Hospital    11    15 
Tax Revenue    11    10 
Education    9    9 
Tobacco    7    6 
Power    6    6 
Housing    5    3 
Lease Revenue    4    4 
Water & Sewer    4    1 

 
 

     Credit Quality Allocations5         
Credit Rating    11/30/08    5/31/08 
AAA/Aaa    35%     47% 
AA/Aa    28    11 
A/A    12    11 
BBB/Baa    13    14 
BB/Ba    1    1 
B/B    1    1 
CCC/Caa    1    3 
Not Rated6    9    12 

5 Using the higher of S&P’s or Moody’s ratings.
6 The investment advisor has deemed certain of these non-rated
securities to be of investment grade quality. As of November 30,
2008 and May 31, 2008, the market value of these securities
was $13,221,856 representing 2% and $20,190,323 represent-
ing 2%, respectively, of the Fund’s long-term investments.

SEMI-ANNUAL REPORT NOVEMBER 30, 2008 5


The Benefits and Risks of Leveraging

The Funds may utilize leverage to seek to enhance the yield and NAV of
their Common Shares. However, these objectives cannot be achieved in all
interest rate environments.

To leverage, BlackRock Muni Intermediate Duration Fund, Inc. issues
Preferred Shares, which pay dividends at prevailing short-term interest
rates, and invests the proceeds in long-term municipal bonds. In general,
the concept of leveraging is based on the premise that the cost of assets
to be obtained from leverage will be based on short-term interest rates,
which normally will be lower than the income earned by the Fund on its
longer-term portfolio investments. To the extent that the total assets of the
Fund (including the assets obtained from leverage) are invested in higher-
yielding portfolio investments, the Fund’s Common Shareholders will
benefit from the incremental yield.

To illustrate these concepts, assume a Fund’s Common Shares capitaliza-
tion is $100 million and it issues Preferred Shares for an additional $50
million, creating a total value of $150 million available for investment in
long-term municipal bonds. If prevailing short-term interest rates are 3%
and long-term interest rates are 6%, the yield curve has a strongly posi-
tive slope. In this case, the Fund pays dividends on the $50 million of
Preferred Shares based on the lower short-term interest rates. At the
same time, the Fund’s total portfolio of $150 million earns the income
based on long-term interest rates. In this case, the dividends paid to
Preferred Shareholders are significantly lower than the income earned
on the Fund’s long-term investments, and therefore the Common Share-
holders are the beneficiaries of the incremental yield.

Conversely, if prevailing short-term interest rates rise above long-term
interest rates of 6%, the yield curve has a negative slope. In this case,
the Fund pays dividends on the higher short-term interest rates where-
as the Fund’s total portfolio earns income based on lower long-term
interest rates. If short-term interest rates rise, narrowing the differential
between short-term and long-term interest rates, the incremental yield
pickup on the Common Shares will be reduced or eliminated completely.

Furthermore, the value of the Fund’s portfolio investments generally varies
inversely with the direction of long-term interest rates, although other
factors can influence the value of portfolio investments. In contrast, the
redemption value of the Fund’s Preferred Shares does not fluctuate in
relation to interest rates. As a result, changes in interest rates can influ-
ence the Fund’s NAV positively or negatively in addition to the impact on
Fund performance from leverage from Preferred Shares discussed above.

The Funds may also from time to time leverage their assets through the
use of tender option bond (“TOB”) programs, as described in Note 1 of
the Notes to Financial Statements. TOB investments generally will provide
the Funds with economic benefits in periods of declining short-term inter-
est rates, but expose the Funds to risks during periods of rising short-term
interest rates similar to those associated with Preferred Shares issued
by BlackRock Muni Intermediate Duration Fund, Inc., as described above.
Additionally, fluctuations in the market value of municipal securities de-
posited into the TOB trust may adversely affect the Funds’ NAVs per share.

The use of leverage may enhance opportunities for increased returns to
the Fund and Common Shareholders, but as described above, it also
creates risks as short- or long-term interest rates fluctuate. Leverage also
will generally cause greater changes in the Funds’ NAV, market price and
dividend rate than a comparable portfolio without leverage. If the income
derived from securities purchased with assets received from leverage
exceeds the cost of leverage, the Funds’ net income will be greater than if
leverage had not been used. Conversely, if the income from the securities
purchased is not sufficient to cover the cost of leverage, the Funds’ net
income will be less than if leverage had not been used, and therefore
the amount available for distribution to shareholders will be reduced. The
Funds may be required to sell portfolio securities at inopportune times or
below fair market values in order to comply with regulatory requirements
applicable to the use of leverage or as required by the terms of leverage
instruments which may cause the Funds to incur losses. The use of lever-
age may limit the Funds’ ability to invest in certain types of securities or
use certain types of hedging strategies, such as in the case of certain
restrictions imposed by ratings agencies that rate preferred shares issued
by a Fund. The Funds will incur expenses in connection with the use of
leverage, all of which are borne by the holders of the Common Shares
and may reduce returns on the Common Shares.

Under the Investment Company Act of 1940, BlackRock Muni Intermediate
Duration Fund, Inc. is permitted to issue Preferred Shares in an amount
of up to 50% of its total managed assets at the time of issuance. Under
normal circumstances, each Fund anticipates that the total economic
leverage from Preferred Shares and TOBs will not exceed 50% of its total
managed assets at the time such leverage is incurred. As of November
30, 2008, the Funds had economic leverage from Preferred Shares and
TOBs as a percentage of their total managed assets as follows:

    Percent of 
    Leverage 
BlackRock MuniAssets Fund, Inc    2% 
BlackRock Muni Intermediate Duration Fund, Inc    42% 

Derivative Instruments

The Funds may invest in various derivative instruments, including futures
contracts and other instruments specified in the Notes to Financials
Statements, which constitute additional forms of economic leverage.
Such instruments are used to obtain exposure to a market without own-
ing or taking physical custody of securities or to hedge market and/or
interest rate risks. Such derivative instruments involve risks, including
the imperfect correlation between the value of a derivative instrument
and the underlying asset, possible default of the other party to the
transaction and illiquidity of the derivative instrument. A Fund’s ability

to successfully use a derivative instrument depends on the Advisor’s
ability to accurately predict pertinent market movements, which cannot
be assured. The use of derivative instruments may result in losses greater
than if they had not been used, may require a Fund to sell or purchase
portfolio securities at inopportune times or for prices other than current
market values, may limit the amount of appreciation a Fund can realize
on an investment or may cause a Fund to hold a security that it might
otherwise sell. The Funds’ investments in these instruments are discussed
in detail in the Notes to Financial Statements.

  6 SEMI-ANNUAL REPORT NOVEMBER 30, 2008


Schedule of Investments November 30, 2008 (Unaudited)    BlackRock MuniAssets Fund, Inc. (MUA) 
                    (Percentages shown are based on Net Assets) 
        Par                    Par     
Municipal Bonds        (000)    Value    Municipal Bonds            (000)    Value 
Alabama — 1.8%                California (concluded)                 
Jefferson County, Alabama, Limited Obligation                Fontana, California, Special Tax, Refunding (Community         
 School Warrants, Series A:                 Facilities District Number 22 — Sierra), 6%, 9/01/34     $ 1,320    $ 972,734 
   5%, 1/01/09    $ 2,300    $ 2,150,155    San Jose, California, Airport Revenue Refunding         
   5%, 1/01/10        685    585,449     Bonds, AMT, Series A, 5.50%, 3/01/32 (c)    4,290    3,359,671 
Tuscaloosa, Alabama, Special Care Facilities Financing            Southern California Public Power Authority,             
 Authority, Residential Care Facility Revenue Bonds                 Natural Gas Project Number 1 Revenue Bonds,         
 (Capstone Village, Inc. Project), Series A, 5.875%,                 Series A, 5%, 11/01/29            2,085    1,331,627 
 8/01/36 (a)        1,820    1,087,304                    8,673,264 
            3,822,908    Colorado — 4.8%                 
Alaska — 0.3%                Colorado Health Facilities Authority, Revenue Refunding         
Alaska Industrial Development and Export Authority                 Bonds (Christian Living Communities Project),         
 Revenue Bonds (Williams Lynxs Alaska Cargoport),             Series A, 5.75%, 1/01/26            650    441,746 
 AMT, 7.80%, 5/01/14        770    726,387    Denver, Colorado, City and County Airport Revenue         
Arizona — 7.6%                 Bonds, AMT, Series D, 7.75%, 11/15/13 (c)    1,540    1,644,951 
Coconino County, Arizona, Pollution Control                Elk Valley, Colorado, Public Improvement Revenue         
 Corporation Revenue Refunding Bonds (Tucson                 Bonds (Public Improvement Fee):             
 Electric Power — Navajo):                   Series A, 7.10%, 9/01/14            1,410    1,364,922 
   AMT, Series A, 7.125%, 10/01/32        3,000    2,372,280       Series A, 7.30%, 9/01/22            2,095    1,878,586 
   Series B, 7%, 10/01/32        2,500    2,048,550       Series B, 7.45%, 9/01/31            260    214,906 
Maricopa County, Arizona, IDA, Education Revenue                North Range Metropolitan District Number 1,         
 Bonds (Arizona Charter Schools Project 1),                 Colorado, GO, 7.25%, 12/15/11 (b)        1,760    1,982,534 
 Series A, 6.625%, 7/01/20        1,625    1,300,244    Plaza Metropolitan District Number 1, Colorado, Tax         
Maricopa County, Arizona, IDA, M/F Housing Revenue             Allocation Revenue Bonds (Public Improvement Fees):         
 Bonds (Sun King Apartments Project), Series A,                   8%, 12/01/25            2,850    2,388,357 
 6.75%, 5/01/31        1,615    1,250,075       8.125%, 12/01/25            525    421,832 
Phoenix, Arizona, IDA, Airport Facility, Revenue Refunding                            10,337,834 
 Bonds (America West Airlines Inc. Project), AMT,                Connecticut — 2.0%                 
 6.30%, 4/01/23        4,800    3,038,832    Connecticut State Development Authority, Airport         
Pima County, Arizona, IDA, Education Revenue Bonds             Facility Revenue Bonds (Learjet Inc. Project),         
 (Arizona Charter Schools Project), Series E, 7.25%,             AMT, 7.95%, 4/01/26            680    600,508 
 7/01/31        1,390    1,184,183    Connecticut State Development Authority, IDR         
Pima County, Arizona, IDA, Education Revenue Refunding             (AFCO Cargo BDL-LLC Project), AMT, 8%, 4/01/30    3,490    3,124,632 
 Bonds (Arizona Charter Schools Project):                Mashantucket Western Pequot Tribe, Connecticut,         
   Series A, 6.75%, 7/01/11 (b)        415    461,638     Revenue Refunding Bonds, Sub-Series A,             
   Series A, 6.75%, 7/01/31        675    538,225     5.50%, 9/01/36            885    567,090 
   Series O, 5.25%, 7/01/31        500    324,620                     
Salt Verde Financial Corporation, Arizona, Senior                                4,292,230 
 Gas Revenue Bonds:                Florida — 10.7%                 
   5%, 12/01/32        2,840    1,856,196    Capital Projects Finance Authority, Florida, Continuing         
   5%, 12/01/37        1,850    1,172,771     Care Retirement Revenue Bonds (Glenridge on Palmer         
Show Low, Arizona, Improvement District Number 5,                 Ranch), Series A, 8%, 6/01/12 (b)        1,130    1,312,212 
 Special Assessment Bonds, 6.375%, 1/01/15        1,000    955,550    Capital Region Community Development District,         
            16,503,164     Florida, Special Assessment Revenue Bonds,         
                 Series A, 7%, 5/01/39            685    537,396 
California — 4.0%                Greater Orlando Aviation Authority, Florida, Airport         
California State, Various Purpose, GO:                 Facilities Revenue Bonds (JetBlue Airways Corp.),         
   5.25%, 11/01/25        1,900    1,809,826     AMT, 6.375%, 11/15/26            1,180    758,244 
   5.50%, 11/01/33        1,300    1,199,406                     
 
     Portfolio Abbreviations                                 
 
   To simplify the listings of portfolio holdings in the    AMT         Alternative Minimum Tax (subject to)    HFA    Housing Finance Agency     
   Schedules of Investments, the names and descrip-    COP         Certificates of Participation    IDA    Industrial Development Authority 
   tions of many of the securities have been abbre -    EDA         Economic Development Authority    IDR    Industrial Development Revenue Bonds 
   viated according to the list on the right:        EDR         Economic Development Revenue Bonds    M/F    Multi-Family         
        GO         General Obligation Bonds    PCR    Pollution Control Revenue Bonds 
        HDA         Housing Development Authority    S/F    Single-Family         

See Notes to Financial Statements.

SEMI-ANNUAL REPORT NOVEMBER 30, 2008 7


Schedule of Investments (continued)    BlackRock MuniAssets Fund, Inc. (MUA) 
            (Percentages shown are based on Net Assets) 
    Par                Par     
Municipal Bonds    (000)    Value    Municipal Bonds        (000)    Value 
Florida (concluded)            Illinois — 4.0%             
Halifax Hospital Medical Center, Florida, Hospital            Chicago, Illinois, O’Hare International Airport,             
 Revenue Refunding Bonds, Series A, 5%, 6/01/38    $ 1,160    $  725,000     Special Facility Revenue Refunding Bonds (American         
Harbor Bay, Florida, Community Development District,             Airlines Inc. Project), 5.50%, 12/01/30    $ 4,140    $ 1,650,908 
 Capital Improvement Special Assessment            Illinois State Finance Authority Revenue Bonds:             
 Revenue Bonds, Series A, 7%, 5/01/33    490    419,234       (Clare At Water Tower Project), Series A, 6.125%,             
Hillsborough County, Florida, IDA, Exempt Facilities               5/15/38        2,950    1,943,371 
 Revenue Bonds (National Gypsum Company),               (Landing At Plymouth Place Project), Series A,             
 AMT, Series A, 7.125%, 4/01/30    2,000    1,254,620       6%, 5/15/37        600    405,666 
Hillsborough County, Florida, IDA, Hospital Revenue               (Monarch Landing, Inc. Project), Series A, 7%,             
 Bonds (Tampa General Hospital Project),               12/01/37        820    626,496 
 5%, 10/01/36    4,170    2,755,202       (Primary Health Care Centers Program),             
Jacksonville, Florida, Economic Development               6.60%, 7/01/24        685    528,861 
 Commission, Health Care Facilities, Revenue            Lincolnshire, Illinois, Special Service Area Number 1,         
 Refunding Bonds (Florida Proton Therapy Institute),             Special Tax Bonds (Sedgebrook Project), 6.25%,             
 Series A, 6%, 9/01/17    920    785,367     3/01/34        1,070    778,254 
Jacksonville, Florida, Economic Development            Lombard, Illinois, Public Facilities Corporation, First Tier         
 Commission, IDR (Gerdau Ameristeel US, Inc.),             Revenue Bonds (Conference Center and Hotel),             
 AMT, 5.30%, 5/01/37    1,300    796,432     Series A-1, 7.125%, 1/01/36        2,600    2,060,292 
Lee County, Florida, IDA, IDR (Lee Charter Foundation),            Village of Wheeling, Illinois, Revenue Bonds (North             
 Series A, 5.375%, 6/15/37    2,620    1,579,493     Milwaukee/Lake-Cook Tax Increment Financing             
Midtown Miami, Florida, Community Development             Redevelopment Project), 6%, 1/01/25        825    616,613 
 District, Special Assessment Revenue Bonds,                        8,610,461 
 Series A, 6.25%, 5/01/37    3,255    2,110,249                 
Orlando, Florida, Urban Community Development            Indiana — 0.8%             
 District, Capital Improvement Special Assessment            Vanderburgh County, Indiana, Redevelopment             
 Bonds, Series A, 6.95%, 5/01/11 (b)    2,245    2,468,984     Commission, Redevelopment District Tax Allocation         
Santa Rosa Bay Bridge Authority, Florida, Revenue             Bonds, 5.25%, 2/01/31        1,200    925,116 
 Bonds, 6.25%, 7/01/28    3,040    2,060,451    Vigo County, Indiana, Hospital Authority Revenue             
Sarasota County, Florida, Health Facilities Authority,             Bonds (Union Hospital, Inc.):             
 Retirement Facility Revenue Refunding Bonds               5.70%, 9/01/37        615    405,107 
 (Village on the Isle Project):               5.75%, 9/01/42        765    493,938 
   5.50%, 1/01/27    860    594,079                1,824,161 
   5.50%, 1/01/32    795    521,814    Iowa — 1.2%             
Sumter Landing Community Development District,            Iowa Finance Authority, Health Care Facilities, Revenue         
 Florida, Recreational Revenue Bonds, Sub-Series B,             Refunding Bonds (Care Initiatives Project), 9.25%,         
 5.70%, 10/01/38    2,405    1,552,187     7/01/11 (b)        2,165    2,577,844 
Tolomato Community Development District, Florida,                         
 Special Assessment Bonds, 6.65%, 5/01/40    2,680    2,002,228    Kansas — 0.3%             
Waterchase, Florida, Community Development District,            Wyandotte County, Kansas, Kansas City Unified             
 Capital Improvement Revenue Bonds, Series A,             Government Revenue Refunding Bonds (General             
 6.70%, 5/01/11 (b)    895    979,058     Motors Corporation Project), 6%, 6/01/25        1,770    557,515 
        23,212,250    Kentucky — 1.4%             
            Kenton County, Kentucky, Airport Board, Special             
Georgia — 2.0%             Facilities Revenue Bonds (Mesaba Aviation Inc.             
Atlanta, Georgia, Tax Allocation Bonds (Princeton             Project), AMT, Series A, 6.70%, 7/01/09 (b)        2,850    2,984,320 
 Lakes Project), 5.50%, 1/01/31    740    505,442                 
Clayton County, Georgia, Tax Allocation Bonds            Louisiana — 2.5%             
 (Ellenwood Project), 7.50%, 7/01/33    2,375    2,020,199    Louisiana Local Government Environmental Facilities         
Main Street Natural Gas, Inc., Georgia, Gas Project             and Community Development Authority Revenue Bonds         
 Revenue Bonds, Series A, 6.375%, 7/15/38 (a)    940    159,819     (Westlake Chemical Corporation), 6.75%, 11/01/32    3,000    2,204,880 
Rockdale County, Georgia, Development Authority            Louisiana Public Facilities Authority, Hospital Revenue         
 Revenue Bonds (Visy Paper Project), AMT, Series A,             Bonds (Franciscan Missionaries of Our Lady Health         
 6.125%, 1/01/34    2,435    1,740,854     System, Inc.), Series A, 5.25%, 8/15/36        1,870    1,385,128 
            Saint John Baptist Parish, Louisiana, Revenue Bonds         
        4,426,314     (Marathon Oil Corporation), Series A, 5.125%, 6/01/37    2,950    1,870,152 
                        5,460,160 

See Notes to Financial Statements.

8 SEMI-ANNUAL REPORT NOVEMBER 30, 2008


Schedule of Investments (continued)    BlackRock MuniAssets Fund, Inc. (MUA) 
                (Percentages shown are based on Net Assets) 
        Par                Par     
Municipal Bonds        (000)    Value    Municipal Bonds        (000)    Value 
Maryland — 1.9%                New Jersey — 10.1%             
Maryland State Economic Development Corporation            Camden County, New Jersey, Pollution Control             
 Revenue Refunding Bonds (Baltimore Association                 Financing Authority, Solid Waste Resource Recovery,         
 for Retarded Citizens-Health and Mental Hygiene                 Revenue Refunding Bonds, AMT:             
 Program), Series A, 7.75%, 3/01/25    $ 1,815    $ 1,737,318       Series A, 7.50%, 12/01/10    $ 9,000     $ 9,011,250 
Maryland State Energy Financing Administration,                   Series B, 7.50%, 12/01/09        125    125,209 
 Limited Obligation Revenue Bonds (Cogeneration-AES            New Jersey EDA, Cigarette Tax Revenue Bonds, 5.50%,         
 Warrior Run), AMT, 7.40%, 9/01/19        1,500    1,254,480     6/15/24        3,065    2,258,384 
Maryland State Health and Higher Educational                New Jersey EDA, IDR, Refunding (Newark Airport             
 Facilities Authority Revenue Bonds:                 Marriott Hotel), 7%, 10/01/14        2,500    2,373,950 
   (King Farm Presbyterian Community),                New Jersey EDA, Retirement Community Revenue             
   Series A, 5.30%, 1/01/37        1,250    755,562     Bonds (Cedar Crest Village Inc. Facility), Series A,             
    (Washington Christian Academy), 5.50%, 7/01/38    590    360,921     7.25%, 11/15/11 (b)        1,665    1,874,907 
            4,108,281    New Jersey EDA, Special Facility Revenue Bonds             
                 (Continental Airlines Inc. Project), AMT:             
Massachusetts — 1.1%                   6.25%, 9/15/19        2,000    1,219,460 
Massachusetts State Health and Educational                   6.25%, 9/15/29        3,330    1,698,333 
 Facilities Authority Revenue Bonds:                   9%, 6/01/33        1,250    914,937 
   (Jordan Hospital), Series E, 6.75%, 10/01/33        1,150    900,185    New Jersey Health Care Facilities Financing Authority         
   (Bay Cove Human Services Issue), Series A,                 Revenue Bonds (Pascack Valley Hospital Association),         
   5.90%, 4/01/28        1,945    1,422,670     6.625%, 7/01/36 (a)        2,000    67,000 
            2,322,855    New Jersey Health Care Facilities Financing Authority,         
Michigan — 1.6%                 Revenue Refunding Bonds (Saint Joseph’s             
Advanced Technology Academy, Michigan, Revenue                 Healthcare System), 6.625%, 7/01/38        2,410    1,815,887 
 Bonds, 6%, 11/01/37        900    653,121    New Jersey State Transportation Trust Fund Authority,         
Macomb County, Michigan, Hospital Finance Authority,             Transportation System Revenue Bonds, Series C,             
 Hospital Revenue Bonds (Mount Clemens General                 5.05%, 12/15/35 (c)(d)        3,450    583,395 
 Hospital), Series B, 5.875%, 11/15/13 (b)        1,635    1,857,131                21,942,712 
Monroe County, Michigan, Hospital Financing Authority,            New Mexico — 1.0%             
 Hospital Revenue Refunding Bonds (Mercy Memorial            Farmington, New Mexico, PCR, Refunding (Tucson             
 Hospital Corporation), 5.50%, 6/01/35        1,740    1,077,878     Electric Power Company — San Juan Project),             
            3,588,130     Series A, 6.95%, 10/01/20        2,500    2,218,100 
Minnesota — 0.8%                New York — 5.6%             
Minneapolis, Minnesota, Health Care System Revenue            Dutchess County, New York, IDA, Civic Facility Revenue         
 Refunding Bonds (Fairview Health Services),                 Refunding Bonds (Saint Francis Hospital), Series A,         
 Series A, 6.75%, 11/15/32        1,785    1,711,494     7.50%, 3/01/29        1,400    1,323,826 
Missouri — 0.3%                Metropolitan Transportation Authority, New York,             
Kansas City, Missouri, IDA, First Mortgage Health                 Revenue Bonds, Series C, 6.50%, 11/15/28        3,685    3,832,768 
 Facilities Revenue Bonds (Bishop Spencer Place),                New York City, New York, City IDA, Civic Facility             
 Series A, 6.50%, 1/01/35        1,000    734,490     Revenue Bonds:             
                   (British Airways Plc Project), AMT, 7.625%, 12/01/32    2,400    1,716,864 
Nevada — 0.6%                   Series C, 6.80%, 6/01/28        510    466,431 
Clark County, Nevada, IDR (Nevada Power Company                   (Special Needs Facilities Pooled Program),             
 Project), AMT, Series A, 5.60%, 10/01/30        1,380    804,678       Series C-1, 6.625%, 7/01/29        1,515    1,200,365 
Clark County, Nevada, Improvement District Number 142,            New York Liberty Development Corporation Revenue             
 Special Assessment Bonds, 6.375%, 8/01/23        635    516,318     Bonds (National Sports Museum Project), Series A,         
            1,320,996     6.125%, 2/15/19 (a)        870    103,878 
New Hampshire — 0.3%                New York State Dormitory Authority, Non-State             
New Hampshire Health and Education Facilities                 Supported Debt, Revenue Refunding Bonds:             
 Authority, Hospital Revenue Bonds (Catholic Medical               (Mount Sinai-NYU Medical Center Health System),         
 Center), 5%, 7/01/36        1,165    724,164       Series C, 5.50%, 7/01/26        1,470    1,231,816 
                   (New York University Hospital Center), Series A,             
                   5%, 7/01/20        2,960    2,257,858 
                Westchester County, New York, IDA, Continuing Care             
                 Retirement, Mortgage Revenue Bonds (Kendal on             
                 Hudson Project), Series A, 6.50%, 1/01/13 (b)        100    115,758 
                            12,249,564 

See Notes to Financial Statements.

SEMI-ANNUAL REPORT NOVEMBER 30, 2008 9


Schedule of Investments (continued)    BlackRock MuniAssets Fund, Inc. (MUA) 
                (Percentages shown are based on Net Assets) 
        Par                Par     
Municipal Bonds        (000)    Value    Municipal Bonds        (000)    Value 
North Carolina — 1.7%                Tennessee — 1.3%             
North Carolina Medical Care Commission, Health                Knox County, Tennessee, Health, Educational and             
 Care Facilities, First Mortgage Revenue Refunding                 Housing Facilities Board, Hospital Facilities Revenue         
 Bonds (Deerfield Episcopal Project), Series A,                 Refunding Bonds (Covenant Health), Series A,             
 6.125%, 11/01/38    $ 2,335    $ 1,885,326     5.06%, 1/01/40 (d)    $ 6,785    $ 574,622 
North Carolina Medical Care Commission, Retirement            Shelby County, Tennessee, Health, Educational and             
 Facilities, First Mortgage Revenue Bonds (Givens                 Housing Facilities Board Revenue Bonds             
 Estates Project), Series A, 6.50%, 7/01/13 (b)        1,500    1,745,790     (Germantown Village):             
            3,631,116       6.25%, 12/01/34        355    254,237 
                   Series A, 7.25%, 12/01/34        2,500    2,037,550 
Ohio — 1.2%                             
Buckeye Tobacco Settlement Financing Authority,                            2,866,409 
 Ohio, Tobacco Settlement Asset-Backed Bonds,                Texas — 3.0%             
 Series A-2, 6.50%, 6/01/47        3,935    2,684,575    Brazos River Authority, Texas, PCR, Refunding (TXU Energy         
Pennsylvania — 8.2%                 Company LLC Project), AMT, Series A, 7.70%, 4/01/33    2,550    1,747,032 
Allegheny County, Pennsylvania, Hospital                Harris County, Texas, Health Facilities Development             
 Development Authority, Revenue Refunding                 Corporation, Hospital Revenue Refunding Bonds             
 Bonds (West Penn Allegheny Health System),                 (Memorial Hermann Healthcare System), Series B,         
 Series A, 5.375%, 11/15/40        3,015    1,671,697     7.125%, 12/01/31        1,500    1,475,850 
Bucks County, Pennsylvania, IDA, Retirement Community            North Texas Tollway Authority, System Revenue Refunding         
 Revenue Bonds (Ann’s Choice Inc.), Series A:                 Bonds, Second Tier, Series F, 6.125%, 1/01/31        3,675    3,346,455 
   6.125%, 1/01/25        200    149,938                6,569,337 
   6.25%, 1/01/35        1,550    1,095,772    Utah — 0.7%             
Harrisburg, Pennsylvania, Authority, University                Carbon County, Utah, Solid Waste Disposal, Revenue         
 Revenue Bonds (Harrisburg University of Science),             Refunding Bonds (Laidlaw Environmental), AMT,             
 Series B, 6%, 9/01/36        900    619,182     Series A, 7.45%, 7/01/17        1,660    1,454,127 
Lancaster County, Pennsylvania, Hospital Authority                             
 Revenue Bonds (Brethren Village Project), Series A:            Virginia — 5.0%             
   6.25%, 7/01/26        685    531,587    Dulles Town Center, Virginia, Community Development         
   6.50%, 7/01/40        590    437,155     Authority, Special Assessment Tax (Dulles Town Center         
Montgomery County, Pennsylvania, IDA, Revenue                 Project), 6.25%, 3/01/26        1,455    1,191,747 
 Bonds (Whitemarsh Continuing Care Project),                Fairfax County, Virginia, EDA, Residential Care             
 6.125%, 2/01/28        2,330    1,601,409     Facilities, Mortgage Revenue Refunding Bonds             
Pennsylvania Economic Development Financing                 (Goodwin House, Inc.):             
 Authority, Exempt Facilities Revenue Bonds, AMT:                   5.125%, 10/01/37        750    440,092 
   (National Gypsum Company), Series A,                   5.125%, 10/01/42        450    257,247 
   6.25%, 11/01/27        3,250    1,861,763    Lexington, Virginia, IDA, Residential Care Facility, Mortgage         
   (Reliant Energy), Series B, 6.75%, 12/01/36        2,810    1,742,144     Revenue Refunding Bonds (Kendal at Lexington),             
Philadelphia, Pennsylvania, Authority for IDR (Air Cargo),             Series A, 5.375%, 1/01/28        540    363,215 
 AMT, Series A, 7.50%, 1/01/25        2,270    1,997,963    Tobacco Settlement Financing Corporation of Virginia,         
Philadelphia, Pennsylvania, Authority for IDR,                 Revenue Refunding Bonds, Senior Series B-1,             
 Commercial Development, 7.75%, 12/01/17        6,440    5,998,796     5%, 6/01/47        1,320    704,590 
                Virginia State, HDA, Commonwealth Mortgage Revenue         
            17,707,406     Bonds, Series H, Sub-Series H-1, 5.375%, 7/01/36 (e)    8,690    7,907,118 
Rhode Island — 1.0%                            10,864,009 
Central Falls, Rhode Island, Detention Facility Corporation,                         
 Revenue Refunding Bonds, 7.25%, 7/15/35        2,495    2,079,757    Washington — 0.5%             
                Washington State Housing Financing Commission,             
South Carolina — 1.8%                 Nonprofit Revenue Bonds (Skyline at First Hill Project),         
Connector 2000 Association, Inc., South Carolina,                 Series A, 5.625%, 1/01/38        1,750    1,098,528 
 Toll Road and Capital Appreciation Revenue Bonds,                         
 Senior-Series B (d):                Wisconsin — 0.7%             
   6.50%, 1/01/09        1,500    1,479,795    Wisconsin State Health and Educational Facilities             
   7.969%, 1/01/14        1,485    824,754     Authority Revenue Bonds (New Castle Place Project),         
South Carolina Jobs, EDA, EDR (Westminster                 Series A, 7%, 12/01/31        1,855    1,498,655 
 Presbyterian Center), 7.75%, 11/15/10 (b)        1,500    1,696,350    Wyoming — 2.2%             
            4,000,899    Sweetwater County, Wyoming, Solid Waste Disposal,         
                 Revenue Refunding Bonds (FMC Corporation Project),         
                 AMT, 5.60%, 12/01/35        3,600    2,203,020 
                Wyoming Municipal Power Agency, Power Supply Revenue         
                 Bonds, Series A, 5.375%, 1/01/42        3,030    2,487,994 
                            4,691,014 

  See Notes to Financial Statements.

10 SEMI-ANNUAL REPORT NOVEMBER 30, 2008


Schedule of Investments (concluded) BlackRock MuniAssets Fund, Inc. (MUA)
(Percentages shown are based on Net Assets)

    Par     
Municipal Bonds    (000)    Value 
U.S. Virgin Islands — 1.1%         
Virgin Islands Government Refinery Facilities, Revenue         
 Refunding Bonds (Hovensa Coker Project), AMT,         
 6.50%, 7/01/21    $ 3,000    $ 2,299,440 
Total Municipal Bonds — 95.1%        206,374,870 
Municipal Bonds Transferred to         
Tender Option Bond Trusts (f)         
Florida — 3.2%         
Miami-Dade County, Florida, Aviation Revenue Refunding     
 Bonds (Miami International Airport), AMT, Series A,         
 5.25%, 10/01/33 (g)    8,870    6,906,626 
Total Municipal Bonds Transferred to         
Tender Option Bond Trusts — 3.2%        6,906,626 
Total Long-Term Investments         
(Cost — $266,907,049) — 98.3%        213,281,496 
 
Short-Term Securities    Shares     
Merrill Lynch Institutional Tax-Exempt Fund,         
 1.08% (h)(i)    4,208,353    4,208,353 
Total Short-Term Securities         
(Cost — $4,208,353) — 1.9%        4,208,353 
Total Investments (Cost — $271,115,402*) — 100.2%    217,489,849 
Other Assets Less Liabilities — 1.8%        3,942,378 
Liability for Trust Certificates, Including         
Interest Expense and Fees Payable — (2.0)%        (4,453,819) 
Net Assets — 100.0%        $ 216,978,408 
 
 * The cost and unrealized appreciation (depreciation) of investments as of 
       November 30, 2008, as computed for federal income tax purposes, were 
       as follows:         
       Aggregate cost        $ 266,282,194 
       Gross unrealized appreciation        $ 2,942,197 
       Gross unrealized depreciation        (56,169,542) 
       Net unrealized depreciation        $ (53,227,345) 

(a) Issuer filed for bankruptcy and/or is in default of interest payments.
(b) U.S. government securities, held in escrow, are used to pay interest on this security
as well as to retire the bond in full at the date indicated, typically at a premium
to par.
(c) AMBAC Insured.
(d) Represents a zero-coupon bond. Rate shown reflects the effective yield at the
time of purchase.
(e) MBIA Insured.

(f) Securities represent bonds transferred to a tender option bond trust in exchange
for which the Fund acquired residual interest certificates. These securities serve
as collateral in a financing transaction. See Note 1 of the Notes to Financial
Statements for details of municipal bonds transfered to tender option bond trusts.
(g) Assured Guaranty Insured.
(h) Investments in companies considered to be an affiliate of the Fund, for purposes
of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:

    Net     
Affiliate    Activity    Income 
Merrill Lynch Institutional Tax-Exempt Fund    1,007,912    $ 68,408 

(i) Represents the current yield as of report date.
Effective June 1, 2008, the Fund adopted Financial Accounting Standards
Board Statement of Financial Accounting Standards No. 157, “Fair Value
Measurements” (“FAS 157”). FAS 157 clarifies the definition of fair value,
establishes a framework for measuring fair values and requires additional
disclosures about the use of fair value measurements. Various inputs are
used in determining the fair value of investments, which are as follows:
Level 1 — price quotations in active markets/exchanges for identical securities
Level 2 — other observable inputs (including, but not limited to: quoted prices
for 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
circumstance, to the extent observable inputs are not available (including the
Fund’s own assumption used in determining the fair value of investments)
The inputs or methodology 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 November 30, 2008 in
determining the fair valuation of the Fund’s investments:

Valuation    Investments in 
Inputs    Securities 
Level 1    $ 4,208,353 
Level 2    213,281,496 
Level 3     
Total    $ 217,489,849 

See Notes to Financial Statements.

SEMI-ANNUAL REPORT NOVEMBER 30, 2008 11


Schedule of Investments November 30, 2008 (Unaudited)    BlackRock Muni Intermediate Duration Fund, Inc. (MUI) 
                    (Percentages shown are based on Net Assets) 
        Par                Par     
Municipal Bonds        (000)    Value    Municipal Bonds    (000)    Value 
Alabama — 2.6%                California (concluded)         
Jefferson County, Alabama, Limited Obligation School            Rowland, California, Unified School District, GO         
 Warrants, Series A:                 (Election of 2000), Series B, 5.25%, 8/01/27 (d)     $ 1,515     $ 1,486,609 
   5.50%, 1/01/21    $ 5,500    $ 3,852,970    Sacramento, California, Special Tax (North Natomas         
   5.25%, 1/01/23        6,500    4,227,210     Community Facilities), Series 4-C:         
Tuscaloosa, Alabama, Special Care Facilities                   5.60%, 9/01/20    585    483,795 
 Financing Authority, Residential Care Facility Revenue               5.75%, 9/01/22    1,715    1,390,196 
 Bonds (Capstone Village, Inc. Project), Series A,                   5.90%, 9/01/23    500    406,195 
 5.625%, 8/01/25        6,600    4,220,766       6%, 9/01/28    2,990    2,300,984 
            12,300,946    Sacramento County, California, Airport System Revenue         
                 Bonds, Senior Series A, 5%, 7/01/28 (d)    1,695    1,571,045 
Arizona — 2.8%                Southern California HFA, S/F Mortgage Revenue         
Maricopa County, Arizona, IDA, Education Revenue                 Bonds, AMT, Series A, 5.80%, 12/01/49 (e)(f)(g)    3,905    3,624,074 
 Bonds (Arizona Charter Schools Project 1), Series A,            Tustin, California, Unified School District, Senior Lien         
 6.625%, 7/01/20        2,820    2,256,423     Special Tax Bonds (Community Facilities District         
Navajo County, Arizona, IDA, IDR (Stone Container                 Number 97-1), Series A, 5%, 9/01/32 (d)    2,610    2,329,973 
 Corporation Project), AMT, 7.20%, 6/01/27        2,500    825,025                 
Pima County, Arizona, IDA, Education Revenue Bonds                        84,231,770 
 (Arizona Charter Schools Project):                Colorado — 2.3%         
   Series C, 6.70%, 7/01/21        985    862,102    Elk Valley, Colorado, Public Improvement Revenue Bonds         
   Series K, 6.375%, 7/01/13 (a)        820    946,231     (Public Improvement Fee), Series A, 7.10%, 9/01/14    700    677,621 
   Series K, 6.375%, 7/01/31        930    706,223    Montrose, Colorado, Memorial Hospital, Revenue Bonds,         
Salt River Project, Arizona, Agriculture Improvement                 6.375%, 12/01/23    2,250    2,039,265 
 and Power District, Electric System Revenue Bonds,            Plaza Metropolitan District Number 1, Colorado,         
 Series A, 5%, 1/01/25        4,000    3,934,720     Tax Allocation Revenue Bonds (Public Improvement         
Vistancia Community Facilities District, Arizona,                 Fees), 7.50%, 12/01/15    7,500    6,833,850 
 GO, 5%, 7/15/14        3,630    3,418,117    Southlands Metropolitan District Number 1, Colorado,         
            12,948,841     GO, 6.75%, 12/01/14 (a)    1,000    1,145,920 
California — 18.1%                            10,696,656 
Antelope Valley, California, Health Care District Revenue            Connecticut — 0.9%         
 Bonds, Series A, 5.25%, 9/01/17        8,000    7,055,520    Connecticut State Development Authority, Airport         
California Pollution Control Financing Authority, PCR,             Facility Revenue Bonds (Learjet Inc. Project),         
 Refunding (Pacific Gas & Electric), AMT, Series A,                 AMT, 7.95%, 4/01/26    1,160    1,024,396 
 5.35%, 12/01/16 (b)        17,730    16,749,176    Connecticut State Development Authority, PCR,         
California Pollution Control Financing Authority, Solid             Refunding (Connecticut Light and Power Company),         
 Waste Disposal Revenue Bonds, AMT:                 Series A, 5.85%, 9/01/28    4,000    3,351,920 
   (Republic Services Inc. Project), Series B,                            4,376,316 
   5.25%, 6/01/23        750    572,340                 
   (Waste Management Inc. Project), Series A-2,                Florida — 7.0%         
   5.40%, 4/01/25        1,240    893,284    Florida Housing Finance Corporation, Homeowner         
California State Department of Water Resources, Power             Mortgage Revenue Bonds, AMT, Series 6,         
 Supply Revenue Bonds, Series A, 5.375%, 5/01/12 (a)    5,000    5,583,850     4.70%, 7/01/37    4,000    2,709,080 
California State, GO:                Harbor Bay, Florida, Community Development         
   5.50%, 4/01/14 (a)        14,795    16,945,305     District, Capital Improvement Special Assessment         
   5.50%, 4/01/28        15    14,650     Bonds, 6.75%, 5/01/34    2,860    2,198,024 
California State, GO, Refunding, 5.25%, 2/01/27 (b)    5,000    4,661,250    Highlands County, Florida, Health Facilities Authority,         
California State Public Works Board, Lease Revenue             Hospital Revenue Refunding Bonds (Adventist Health         
Bonds (Department of Corrections), Series C,                 System), Series G, 5.125%, 11/15/16 (a)    35    38,628 
 5.50%, 6/01/20        10,000    10,073,400    Miami-Dade County, Florida, Aviation Revenue         
California Statewide Communities Development                 Refunding Bonds (Miami International Airport),         
 Authority, Health Facility Revenue Bonds (Memorial             AMT, 5.75%, 10/01/19 (c)(h)    5,500    5,085,300 
 Health Services), Series A, 6%, 10/01/23        2,500    2,458,825    Miami-Dade County, Florida, Water and Sewer Revenue         
Golden State Tobacco Securitization Corporation of                 Refunding Bonds, Series C, 5%, 10/01/23 (i)    10,000    9,509,200 
 California, Tobacco Settlement Revenue Refunding            Midtown Miami, Florida, Community Development         
 Bonds, Senior Series A-1, 5%, 6/01/15        5,000    4,486,700     District, Special Assessment Revenue Bonds:         
Los Angeles, California, Regional Airports Improvement               Series A, 6%, 5/01/24    3,465    2,438,910 
 Corporation, Facilities Lease Revenue Refunding                   Series B, 6.50%, 5/01/37    1,975    1,326,706 
 Bonds (LAXFUEL Corporation — Los Angeles                Orlando, Florida, Urban Community Development         
 International Airport), AMT, 5.50%, 1/01/32 (c)        1,435    1,144,599     District, Capital Improvement Special Assessment         
                 Bonds, 6%, 5/01/20    820    654,048 

See Notes to Financial Statements.

12 SEMI-ANNUAL REPORT NOVEMBER 30, 2008


Schedule of Investments (continued)    BlackRock Muni Intermediate Duration Fund, Inc. (MUI) 
                (Percentages shown are based on Net Assets) 
        Par                Par     
Municipal Bonds        (000)    Value    Municipal Bonds        (000)    Value 
Florida (concluded)                Maine — 0.3%             
Panther Trace Community Development District II,                Portland, Maine, Housing Development Corporation,         
 Florida, Special Assessment Revenue Bonds,                 Senior Living Revenue Bonds (Avesta Housing             
 5.125%, 11/01/13    $ 2,255     $ 1,905,295     Development Corporation Project), Series A,             
Portofino Shores, Florida, Community Development                 6%, 2/01/34    $ 1,965    $ 1,483,870 
 District, Special Assessment Bonds, Series A,                Maryland — 0.1%             
 6.40%, 5/01/34        1,085    858,463    Maryland State Industrial Development Financing             
South Lake County, Florida, Hospital District Revenue             Authority, EDR (Our Lady of Good Counsel School),         
 Bonds (South Lake Hospital Inc.), 6.625%, 10/01/23    2,390    2,178,485     Series A, 6%, 5/01/35        500    349,570 
Sterling Hill Community Development District, Florida,                         
 Capital Improvement Revenue Refunding Bonds,                Massachusetts — 1.6%             
 Series B, 5.50%, 11/01/10        175    167,323    Massachusetts Bay Transportation Authority, Sales             
University of Florida Research Foundation Inc., Capital             Tax Revenue Refunding Bonds, Senior Series A,             
 Improvement Revenue Bonds, 5.125%, 9/01/33 (c)    4,000    3,555,960     5%, 7/01/12 (a)        4,560    4,963,925 
                Massachusetts State Development Finance Agency,             
            32,625,422     Resource Recovery Revenue Bonds (Ogden Haverhill         
Idaho — 0.8%                 Associates), AMT, Series B:             
Boise City, Idaho, COP, AMT, 5.50%, 9/01/25 (b)(h)    4,000    3,289,680       5.35%, 12/01/15        1,210    1,043,407 
Idaho Housing and Finance Association, S/F Mortgage               5.50%, 12/01/19        2,000    1,650,160 
 Revenue Bonds, AMT, Series F-2, 5.85%, 7/01/15 (j)    260    262,072                7,657,492 
            3,551,752    Michigan — 1.5%             
Illinois — 5.8%                Macomb County, Michigan, Hospital Finance Authority,         
Chicago, Illinois, O’Hare International Airport, General             Hospital Revenue Bonds (Mount Clemens General             
 Airport Revenue Bonds, Third Lien, AMT, Series B-2,             Hospital), Series B, 5.875%, 11/15/13 (a)        2,325    2,640,874 
 6%, 1/01/29 (k)        2,510    2,133,625    Michigan State Hospital Finance Authority, Revenue             
Chicago, Illinois, O’Hare International Airport, General             Refunding Bonds (Oakwood Obligated Group),             
 Airport Revenue Refunding Bonds, Third Lien, AMT,                 Series A, 6%, 4/01/22        4,795    4,497,470 
 Series A-2, 5.75%, 1/01/19 (d)        2,550    2,379,507                7,138,344 
Du Page and Will Counties, Illinois, Community School                         
 District Number 204 (Indian Prairie), GO,                Minnesota — 1.1%             
 5.25%, 12/30/22 (b)(h)        8,650    8,756,914    Minneapolis and Saint Paul, Minnesota, Housing             
Hodgkins, Illinois, Environmental Improvement Revenue             and Redevelopment Authority, Health Care System             
 Bonds (Metro Biosolids Management LLC Project),             Revenue Bonds (Group Health Plan Inc. Project):             
 AMT, 5.90%, 11/01/17        6,000    5,231,220       6%, 12/01/19        1,000    921,240 
Illinois, Development Finance Authority Revenue Bonds               6%, 12/01/21        2,545    2,252,529 
 (Community Rehabilitation Providers Facilities),                Minnesota State Municipal Power Agency, Electric             
 Series A, 6.625%, 7/01/32        6,930    6,100,825     Revenue Bonds, Series A, 5.25%, 10/01/24        2,000    1,819,260 
Illinois State Finance Authority Revenue Bonds (Landing                        4,993,029 
 At Plymouth Place Project), Series A, 6%, 5/15/25    1,800    1,335,798    Mississippi — 1.3%             
Village of Wheeling, Illinois, Revenue Bonds (North                Mississippi Business Finance Corporation,             
 Milwaukee/Lake-Cook Tax Increment Financing                 Mississippi, PCR, Refunding (System Energy             
 Redevelopment Project), 6%, 1/01/25        1,580    1,180,908     Resources Inc. Project):             
            27,118,797       5.875%, 4/01/22        5,000    3,952,000 
Indiana — 0.4%                   5.90%, 5/01/22        2,910    2,303,905 
Jasper County, Indiana, PCR, Refunding (Northern                            6,255,905 
 Indiana Public Service), Series C, 5.85%, 4/01/19 (b)    2,000    1,844,960    Nebraska — 0.9%             
Louisiana — 2.7%                Public Power Generation Agency, Nebraska, Revenue         
Louisiana Public Facilities Authority Revenue Bonds:             Bonds (Whelan Energy Center Unit 2), Series A,             
  (Nineteenth Judicial District Court Building Project),             5%, 1/01/37 (c)        5,000    4,182,950 
   5.50%, 6/01/41 (h)        2,000    1,765,620    Nevada — 0.4%             
  (University of New Orleans Research and Technology            Clark County, Nevada, Improvement District Number 142,         
   Foundation, Inc. — Student Housing Project),                 Special Assessment Bonds, 6.375%, 8/01/23        2,195    1,784,754 
   5.25%, 3/01/26 (b)        6,965    6,442,834                 
Port New Orleans, Louisiana, IDR, Refunding (Continental                         
 Grain Company Project), 6.50%, 1/01/17        5,000    4,259,550                 
            12,468,004                 

  See Notes to Financial Statements.

SEMI-ANNUAL REPORT NOVEMBER 30, 2008 13


Schedule of Investments (continued)    BlackRock Muni Intermediate Duration Fund, Inc. (MUI) 
                (Percentages shown are based on Net Assets) 
        Par            Par     
Municipal Bonds        (000)    Value    Municipal Bonds    (000)    Value 
New Jersey — 13.1%                New York (concluded)         
Garden State Preservation Trust of New Jersey,                New York State Dormitory Authority, Non-State Supported         
 Open Space and Farmland Preservation Revenue                 Debt, Lease Revenue Bonds (Municipal Health Facilities         
 Bonds, Series A (d):                 Improvement Program), Sub-Series 2-4, 5%, 1/15/27     $ 6,900    $ 6,350,691 
   5.80%, 11/01/21    $ 3,635    $ 3,859,352    New York State Dormitory Authority, Non-State         
   5.80%, 11/01/23        5,050    5,286,794     Supported Debt, Revenue Refunding Bonds (Mount         
New Jersey EDA, Cigarette Tax Revenue Bonds,                 Sinai-NYU Medical Center Health System), Series A:         
 5.75%, 6/15/29        9,810    7,061,238       6.625%, 7/01/10 (a)    4,615    5,016,043 
New Jersey EDA, Motor Vehicle Surcharge Revenue                   6.625%, 7/01/18    2,385    2,405,344 
 Bonds, Series A, 5.25%, 7/01/33 (b)        17,900    16,818,124       6.625%, 7/01/19    1,330    1,337,887 
New Jersey EDA, Special Facility Revenue Bonds                New York State Dormitory Authority Revenue Bonds:         
 (Continental Airlines Inc. Project), AMT,                   (North Shore — Long Island Jewish Health System),         
 6.625%, 9/15/12        5,540    4,457,650       5%, 5/01/12    1,000    1,041,990 
New Jersey EDA, Water Facilities Revenue Refunding                   (School Districts Financing Program), Series D,         
 Bonds (American Water), AMT, Series B,                   5.25%, 10/01/23 (b)    9,540    9,471,312 
 5.125%, 4/01/22 (c)        5,000    4,114,850    New York State Environmental Facilities Corporation,         
New Jersey State Housing and Mortgage Finance                 State Personal Income Tax Revenue Bonds, Series A,         
 Agency, S/F Housing Revenue Bonds, AMT, Series X,             5.25%, 12/15/14 (a)(h)    7,380    8,367,001 
 5.10%, 10/01/23        4,500    3,948,345    New York State Thruway Authority, Local Highway and         
New Jersey State Transportation Trust Fund Authority,                 Bridge Service Contract, Revenue Refunding Bonds,         
 Transportation System Revenue Bonds, Series D:                 5.50%, 4/01/17    60    63,776 
   5%, 6/15/18 (c)        4,215    4,309,037    New York State Urban Development Corporation,         
   5%, 6/15/19 (d)        11,120    11,220,970     Correctional and Youth Facilities Services, Revenue         
            61,076,360     Refunding Bonds, Series A, 5.50%, 1/01/17    10,825    11,156,028 
                New York State Urban Development Corporation,         
New Mexico — 2.1%                 Personal Income Tax Revenue Bonds (State Facilities),         
New Mexico Finance Authority, Senior Lien State                 Series A-1, 5.25%, 3/15/34 (b)(h)    10,000    9,592,600 
 Transportation Revenue Bonds, Series A,                Port Authority of New York and New Jersey, Consolidated         
 5.125%, 6/15/18 (b)        9,520    9,877,095     Revenue Refunding Bonds, 153rd Series, 5%, 7/15/24    2,010    1,979,890 
New York — 27.8%                Port Authority of New York and New Jersey, Senior         
Dutchess County, New York, IDA, Civic Facility                 Consolidated Revenue Bonds, AMT, 131st Series,         
 Revenue Bonds (Saint Francis Hospital), Series B,                 5%, 12/15/17 (l)    5,000    4,711,900 
 7.25%, 3/01/19        1,030    968,571    Tobacco Settlement Financing Corporation of New York         
Metropolitan Transportation Authority, New York,                 Revenue Bonds:         
 Revenue Refunding Bonds, Series A, 5%, 11/15/25 (h)    3,600    3,241,260       Series A-1, 5.25%, 6/01/22 (c)    6,510    6,177,795 
New York City, New York, City IDA, Special Facility                   Series C-1, 5.50%, 6/01/20 (h)    9,750    9,692,475 
 Revenue Bonds (Continental Airlines Inc. Project),                   Series C-1, 5.50%, 6/01/21    7,000    6,875,960 
 AMT, 8.375%, 11/01/16        3,500    2,603,230       Series C-1, 5.50%, 6/01/22    10,000    9,721,600 
New York City, New York, City Transitional Finance                        129,780,635 
 Authority, Building Aid Revenue Bonds, Series S-1,                         
 5%, 7/15/24 (h)        2,500    2,357,375    North Carolina — 0.9%         
New York City, New York, GO, Refunding, Series B,                Gaston County, North Carolina, Industrial Facilities and         
 5.75%, 8/01/15        5,000    5,361,150     Pollution Control Financing Authority, Revenue Bonds         
New York City, New York, GO, Series D1, 5.125%,                 (National Gypsum Company Project), AMT,         
 12/01/26        4,615    4,343,361     5.75%, 8/01/35    3,105    1,684,214 
New York City, New York, IDA, Civic Facility Revenue                North Carolina Municipal Power Agency Number 1,         
 Bonds (Special Needs Facilities Pooled Program),                 Catawba Electric Revenue Bonds, Series A,         
 Series C-1, 6.80%, 7/01/19        2,055    1,774,554     5.25%, 1/01/20 (b)    2,700    2,644,353 
New York City, New York, Sales Tax Asset                        4,328,567 
 Receivable Corporation Revenue Bonds,                Ohio — 0.9%         
 Series A, 5%, 10/15/20 (b)        9,070    9,273,349    Buckeye Tobacco Settlement Financing Authority,         
New York State Dormitory Authority, Lease                 Ohio, Tobacco Settlement Asset-Backed Bonds,         
 Revenue Refunding Bonds (Court Facilities),                 Series A-2, 6.50%, 6/01/47    4,820    3,288,349 
 Series A, 5.25%, 5/15/12        5,580    5,895,493    Port of Greater Cincinnati Development Authority,         
                 Ohio, Special Assessment Revenue Bonds         
                 (Cooperative Public Parking Infrastructure         
                 Project), 6.30%, 2/15/24    1,280    1,011,187 
                        4,299,536 

See Notes to Financial Statements.

14 SEMI-ANNUAL REPORT NOVEMBER 30, 2008


Schedule of Investments (continued)    BlackRock Muni Intermediate Duration Fund, Inc. (MUI) 
            (Percentages shown are based on Net Assets) 
    Par                Par     
Municipal Bonds    (000)    Value    Municipal Bonds        (000)    Value 
Pennsylvania — 9.4%            Texas — 11.0%             
Montgomery County, Pennsylvania, IDA, Revenue Bonds            Austin, Texas, Convention Center Revenue Bonds             
 (Whitemarsh Continuing Care Project), 6%, 2/01/21     $ 3,500    $ 2,624,440     (Convention Enterprises Inc.), First Tier, Series A,             
Pennsylvania Economic Development Financing Authority,             6.375%, 1/01/11 (a)    $ 5,945    $ 6,396,523 
 Exempt Facilities Revenue Bonds (National Gypsum            Bexar County, Texas, Health Facilities Development             
 Company), AMT, Series A, 6.25%, 11/01/27    7,710    4,416,673     Corporation, Revenue Refunding Bonds (Army             
Philadelphia, Pennsylvania, Airport Revenue Bonds             Retirement Residence Project), 6.30%, 7/01/12 (a)    1,500    1,681,335 
 (Philadelphia Airport System), AMT, Series A,            Brazos River Authority, Texas, PCR, Refunding             
 5%, 6/15/20 (d)    2,895    2,493,058     (TXU Energy Company Project), AMT, Series C,             
Philadelphia, Pennsylvania, Airport Revenue Refunding             5.75%, 5/01/36        7,000    5,434,870 
 Bonds (Philadelphia Airport System), AMT, Series B,            Dallas-Fort Worth, Texas, International Airport Facility         
 5%, 6/15/19 (d)    3,905    3,439,797     Improvement Corporation, Revenue Bonds (Learjet Inc.),         
Philadelphia, Pennsylvania, Gas Works Revenue             AMT, Series A-1, 6.15%, 1/01/16        4,000    3,304,400 
 Refunding Bonds, 1975 General Ordinance, 17th Series,            Dallas-Fort Worth, Texas, International Airport Facility         
 5.375%, 7/01/22 (d)    7,490    7,509,249     Improvement Corporation, Revenue Refunding Bonds,         
Pittsburgh, Pennsylvania, GO, Refunding, Series B,             AMT, Series A-2, 9%, 5/01/29        3,000    1,620,510 
 5.25%, 9/01/17 (d)    9,630    10,046,594    Dallas-Fort Worth, Texas, International Airport, Joint             
Pittsburgh, Pennsylvania, GO, Series C,             Revenue Refunding Bonds, AMT, Sub-Series A-2,             
 5.25%, 9/01/18 (d)    6,430    6,626,436     6.10%, 11/01/24 (b)        1,500    1,357,920 
Sayre, Pennsylvania, Health Care Facilities Authority,            Gulf Coast, Texas, IDA, Solid Waste Disposal Revenue         
 Revenue Refunding Bonds (Guthrie Healthcare             Bonds (Citgo Petroleum Corporation Project), AMT,             
 System), Series A:             7.50%, 5/01/25        2,440    2,317,366 
   6.25%, 12/01/11 (a)    4,615    5,169,631    Gulf Coast Waste Disposal Authority, Texas, Revenue             
   6.25%, 12/01/15    455    463,527     Refunding Bonds (International Paper Company),             
   6.25%, 12/01/16    785    796,571     AMT, Series A, 6.10%, 8/01/24        2,000    1,386,220 
   6.25%, 12/01/18    385    386,213    Houston, Texas, Airport System Revenue Refunding Bonds,         
        43,972,189     Sub-Lien, AMT, Series A, 5.50%, 7/01/23 (d)        5,790    5,003,486 
            Houston, Texas, Health Facilities Development Corporation,         
South Carolina — 2.5%             Retirement Facility Revenue Bonds (Buckingham Senior         
Georgetown County, South Carolina, Pollution Control             Living Community), Series A, 7%, 2/15/14 (a)        1,500    1,728,465 
 Facilities, Revenue Refunding Bonds (International            Lower Colorado River Authority, Texas, PCR (Samsung         
 Paper Company Project), Series A, 5.125%, 2/01/12    8,000    7,376,800     Austin Semiconductor), AMT, 6.95%, 4/01/30        7,420    6,209,279 
Medical University Hospital Authority, South Carolina,            Sabine River Authority, Texas, PCR, Refunding             
 Hospital Facilities Revenue Refunding Bonds,             (TXU Electric Company Project/TXU Energy Company LLC),         
 Series A, 5.25%, 8/15/23 (b)(j)    4,250    4,145,067     AMT, Series B, 5.75%, 5/01/30        5,000    3,882,050 
        11,521,867    Texas State Affordable Housing Corporation, S/F             
South Dakota — 0.4%             Mortgage Revenue Bonds (Professional Educators             
Educational Enhancement Funding Corporation,             Home Loan Program), AMT (e)(f)(g):             
 South Dakota, Series B, 6.50%, 6/01/32    2,200    1,727,858       Series A-3, 5.60%, 2/01/39        7,889    6,809,166 
               Series B, 5.95%, 12/01/39        4,757    4,360,409 
Tennessee — 3.9%                         
Johnson City, Tennessee, Health and Educational Facilities                        51,491,999 
 Board, Retirement Facility Revenue Bonds (Appalachian            Virginia — 2.7%             
 Christian Village Project), Series A, 6%, 2/15/19    1,800    1,442,826    James City County, Virginia, IDA, Residential Care             
Memphis-Shelby County, Tennessee, Airport Authority,             Facility Revenue Refunding Bonds, Series A:             
 Airport Revenue Bonds, AMT, Series A, 5.50%,               5.75%, 3/01/17        3,285    2,804,043 
 3/01/17 (d)    2,005    1,920,008       6%, 3/01/23        1,150    903,624 
Shelby County, Tennessee, Health, Educational            Tobacco Settlement Financing Corporation of Virginia,         
 & Housing Facilities Board Revenue Bonds             Asset-Backed Revenue Bonds, 5.625%, 6/01/15 (a)    7,800    8,713,926 
 (Germantown Village), Series A:                        12,421,593 
   6.75%, 12/01/18    3,550    3,106,463                 
   7%, 12/01/23    1,450    1,214,767    Washington — 2.2%             
Shelby County, Tennessee, Health, Educational and            Snohomish County, Washington, School District             
 Housing Facility Board, Hospital Revenue Refunding             Number 015 (Edmonds), GO, 5%, 12/01/19 (b)(h)    10,000    10,205,000 
 Bonds (Methodist Healthcare)(a):                         
   6%, 9/01/12    745    820,022                 
   6%, 9/01/12    5,255    5,784,180                 
   6.25%, 9/01/12    3,500    3,883,250                 
        18,171,516                 

See Notes to Financial Statements.

SEMI-ANNUAL REPORT NOVEMBER 30, 2008 15


Schedule of Investments (continued)    BlackRock Muni Intermediate Duration Fund, Inc. (MUI) 
                (Percentages shown are based on Net Assets) 
        Par        Municipal Bonds Transferred to        Par     
Municipal Bonds        (000)    Value    Tender Option Bond Trusts (o)        (000)    Value 
Guam — 1.0%                California — 5.5%             
Commonwealth of the Northern Mariana Islands,                Peralta, California, Community College District, GO             
 Guam, GO, Series A:                 (Election of 2000), Series D, 5%, 8/01/30 (d)    $ 10,140    $ 9,465,284 
   6.75%, 10/01/13 (a)    $ 4,000    $ 4,638,960    San Jose, California, GO (Libraries, Parks and Public             
   6.75%, 10/01/33        250    200,280     Safety Projects), 5%, 9/01/30 (b)        3,101    2,894,161 
            4,839,240    Sequoia, California, Unified High School District, GO,             
                 Refunding, Series B, 5.50%, 7/01/35 (d)        9,028    8,866,921 
Puerto Rico — 13.1%                Tamalpais, California, Union High School District, GO             
Puerto Rico Commonwealth Aqueduct and Sewer                 (Election of 2001), 5%, 8/01/28 (d)        4,875    4,481,588 
 Authority, Senior Lien Revenue Bonds, Series A,                             
 5%, 7/01/25 (m)        3,215    2,959,182                25,707,954 
Puerto Rico Commonwealth Highway and Transportation            Illinois — 2.6%             
 Authority, Subordinate Transportation Revenue Bonds,            McHenry County, Illinois, Conservation District, GO,             
 5.75%, 7/01/21 (h)        4,375    4,054,706     5.125%, 2/01/27 (d)        12,695    12,335,573 
Puerto Rico Electric Power Authority, Power Revenue                Massachusetts — 1.7%             
 Bonds, Series NN, 5.50%, 7/01/13 (a)        17,935    20,172,033    Massachusetts State School Building Authority,             
Puerto Rico Housing Financing Authority, Capital Funding             Dedicated Sales Tax Revenue Bonds, Series A, 5%,             
 Program, Subordinate Revenue Refunding Bonds,                 8/15/30 (d)        8,338    7,903,887 
 5.125%, 12/01/27        13,900    12,842,905                 
Puerto Rico Industrial, Medical and Environmental                New York -2.4%             
 Pollution Control Facilities Financing Authority, Special            New York City, New York, Sales Tax Asset Receivable             
 Facilities Revenue Bonds (American Airlines Inc.),                 Corporation Revenue Bonds, Series A, 5.25%,             
 Series A, 6.45%, 12/01/25        5,390    2,214,482     10/15/27 (c)        11,100    11,115,984 
Puerto Rico Public Buildings Authority, Government                Texas — 7.1%             
 Facilities Revenue Refunding Bonds:                Harris County, Texas, Toll Road Revenue Refunding             
   Series D, 5.25%, 7/01/27        5,170    4,204,451     Bonds, Senior Lien, Series A, 5.25%, 8/15/35 (d)        31,240    33,050,045 
   Series I, 5.50%, 7/01/14 (a)(n)        8,000    8,865,840    Total Municipal Bonds Transferred to             
   Series M-3, 6%, 7/01/28 (b)(n)        1,900    1,713,876    Tender Option Bond Trusts — 19.3%            90,113,443 
Puerto Rico Public Finance Corporation, Commonwealth                         
 Appropriation Revenue Bonds, Series E, 5.50%,                Total Long-Term Investments             
 2/01/12 (a)        3,535    3,827,698    (Cost — $828,744,059) — 162.3%            757,114,398 
            60,855,173                 
U.S. Virgin Islands — 1.4%                             
Virgin Islands Government Refinery Facilities,                Short-Term Securities        Shares     
 Revenue Refunding Bonds (Hovensa Coker Project),            Merrill Lynch Institutional Tax-Exempt Fund,             
 AMT, 6.50%, 7/01/21        1,860    1,425,653     1.08% (p)(q)    43,643,528    43,643,528 
Virgin Islands Public Finance Authority, Refinery                Total Short-Term Securities             
 Facilities Revenue Bonds (Hovensa Refinery), AMT,            (Cost — $43,643,528) — 9.4%            43,643,528 
 6.125%, 7/01/22        6,750    4,997,296                 
            6,422,949    Total Investments (Cost — $872,387,587*) — 171.7%        800,757,926 
                Other Assets Less Liabilities — 1.4%            6,671,953 
Total Municipal Bonds — 143.0%            667,000,955    Liability for Trust Certificates, Including             
                Interest Expense and Fees Payable — (11.5)%            (53,710,040) 
                Preferred Shares, at Redemption Value — (61.6)%            (287,281,675) 
                Net Assets Applicable to Common Shares — 100.0%    $ 466,438,164 

See Notes to Financial Statements.

16 SEMI-ANNUAL REPORT NOVEMBER 30, 2008


Schedule of Investments (concluded) BlackRock Muni Intermediate Duration Fund, Inc. (MUI)

*  The cost and unrealized appreciation (depreciation) of investments as of 
  November 30, 2008, as computed for federal income tax purposes, were 
  as follows:     
  Aggregate cost    $ 819,494,751 
  Gross unrealized appreciation    $ 12,374,117 
  Gross unrealized depreciation    (84,393,746) 
  Net unrealized depreciation    $ (72,019,629) 

(a) U.S. government securities, held in escrow, are used to pay interest on this
security as well as to retire the bond in full at the date indicated, typically at
a premium to par.
(b) MBIA Insured.
(c) AMBAC Insured.
(d) FSA Insured.
(e) FNMA Collateralized.
(f) GNMA Collateralized.
(g) FHLMC Collateralized.
(h) FGIC Insured.
(i) BHAC Insured.
(j) FHA Insured.
(k) XL Capital Insured.
(l) CIFG Insured.
(m) Assured Guaranty Insured.
(n) Commonwealth Guaranteed.
(o) Securities represent bonds transferred to a tender option bond trust in
exchange for which the Fund acquired residual interest certificates. These
securities serve as collateral in a financing transaction. See Note 1 of the
Notes to Financial Statements for details of municipal bonds transferred to
tender option bond trusts.
(p) Investments in companies considered to be an affiliate of the Fund, for purposes
of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:

    Net     
     Affiliate    Activity    Income 
     Merrill Lynch Institutional Tax-Exempt Fund    43,643,528    $ 122,165 
(q) Represents the current yield as of report date.         

Effective June 1, 2008, the Fund adopted Financial Accounting Standards
Board Statement of Financial Accounting Standards No. 157, “Fair Value
Measurements” (“FAS 157”). FAS 157 clarifies the definition of fair value,
establishes a framework for measuring fair values and requires additional
disclosures about the use of fair value measurements. Various inputs are
used in determining the fair value of investments, which are as follows:
Level 1 — price quotations in active markets/exchanges for identical securities
Level 2 — other observable inputs (including, but not limited to: quoted prices
for 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
circumstance, to the extent observable inputs are not available (including the
Fund’s own assumption used in determining the fair value of investments)
The inputs or methodology 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 November 30, 2008 in
determining the fair valuation of the Fund’s investments:

Valuation    Investments in 
Inputs    Securities 
Level 1    $ 43,643,528 
Level 2    757,114,398 
Level 3     
Total    $ 800,757,926 

See Notes to Financial Statements.

SEMI-ANNUAL REPORT NOVEMBER 30, 2008 17


Statements of Assets and Liabilities         
        BlackRock 
        Muni 
    BlackRock    Intermediate 
    MuniAssets         Duration 
November 30, 2008 (Unaudited)    Fund, Inc. (MUA)    Fund, Inc. (MUI) 
     Assets         
Investments at value — unaffiliated1    $ 213,281,496    $ 757,114,398 
Investments at value — affiliated2    4,208,353    43,643,528 
Cash    42,671    141,771 
Interest receivable    5,235,059    14,594,711 
Investments sold receivable    220,000    4,094,044 
Dividends receivable        171 
Prepaid expenses    11,858    53,651 
Other assets    239    20,026 
Total assets    222,999,676    819,662,300 
 
     Liabilities         
Investments purchased payable        9,634,800 
Income dividends payable — Common Shares    1,411,209    2,206,026 
Investment advisory fees payable    103,301    295,575 
Interest expense payable    18,819    427,236 
Officer’s and Directors’ fees payable    10,112    41,660 
Other affiliates payable    1,805    5,815 
Other accrued expenses payable    41,022    48,545 
Total accrued liabilities    1,586,268    12,659,657 
 
     Other Liabilities         
Trust certificates3    4,435,000    53,282,804 
Total Liabilities    6,021,268    65,942,461 
 
     Preferred Shares at Redemption Value         
Preferred Shares, at $0.10 par value per share4 at $25,000 per share liquidation preference, plus unpaid dividends        287,281,675 
Net Assets Applicable to Common Shareholders    $ 216,978,408    $ 466,438,164 
 
     Net Assets Applicable to Common Shareholders Consist of         
Common Shares, par value $0.10 per share    $ 2,090,679    $ 3,803,493 
Paid-in capital in excess of par    296,567,307    536,698,013 
Undistributed net investment income    1,305,344    2,046,022 
Accumulated net realized loss    (29,359,369)    (4,479,703) 
Net unrealized appreciation/depreciation    (53,625,553)    (71,629,661) 
Net Assets Applicable to Common Shareholders    $ 216,978,408    $ 466,438,164 
Net asset value per Common Share5    $ 10.38    $ 12.26 
   
 
   1 Investments at cost — unaffiliated    $ 266,907,049    $ 828,744,059 
   2 Investments at cost — affiliated    4,208,353    43,643,528 
   3 Represents short-term floating rate certificates issued by tender option bond trusts.         
   4 Preferred Shares outstanding        11,487 
   5 Common Shares issued and outstanding    20,906,793    38,034,934 

See Notes to Financial Statements.

18 SEMI-ANNUAL REPORT

NOVEMBER 30, 2008


Statements of Operations         
        BlackRock 
                 Muni 
    BlackRock    Intermediate 
    MuniAssets         Duration 
Six Months Ended November 30, 2008 (Unaudited)    Fund, Inc. (MUA)    Fund, Inc. (MUI) 
 
     Investment Income         
Interest    $ 9,040,261    $ 21,597,774 
Income — affiliated    68,408    123,039 
Total income    9,108,669    21,720,813 
 
     Expenses         
Investment advisory    711,674    2,350,036 
Commissions for Preferred Shares        358,762 
Accounting services    45,036    93,466 
Professional    33,862    124,965 
Printing    27,978    34,991 
Transfer agent    16,630    38,907 
Officer and Directors    15,140    23,712 
Custodian    8,266    20,835 
Registration    5,133    6,632 
Miscellaneous    25,412    51,158 
Total expenses excluding interest expense and fees    889,131    3,103,464 
Interest expense and fees1    121,752    786,448 
Total expenses    1,010,883    3,889,912 
Less fees waived by advisor    (5,763)    (508,458) 
Total expenses after waiver    1,005,120    3,381,454 
Net investment income    8,103,549    18,339,359 
 
     Realized and Unrealized Gain (Loss)         
Net realized gain (loss) from:         
   Investments    (591,302)    (2,584,733) 
   Futures    259,342     
    (331,960)    (2,584,733) 
Net change in unrealized appreciation/depreciation on:         
   Investments    (49,658,415)    (78,985,745) 
   Futures    (115,218)     
    (49,773,633)    (78,985,745) 
Total realized and unrealized loss    (50,105,593)    (81,570,478) 
 
     Dividends to Preferred Shareholders From         
Net investment income        (6,510,000) 
Net Decrease in Net Assets Applicable to Common Shareholders Resulting from Operations    $ (42,002,044)    $ (69,741,119) 
 
   1 Related to tender option bond trusts.         

See Notes to Financial Statements.

SEMI-ANNUAL REPORT

NOVEMBER 30, 2008

19


Statements of Changes in Net Assets                 
 
    BlackRock    BlackRock Muni Intermediate 
    MuniAssets Fund Inc. (MUA)    Duration Fund, Inc. (MUI) 
    Six Months        Six Months     
    Ended        Ended     
    November 30,         Year Ended    November 30,       Year Ended 
    2008    May 31,    2008         May 31, 
Increase (Decrease) in Net Assets Applicable to Common Shareholders:    (Unaudited)    2008    (Unaudited)    2008 
     Operations                 
Net investment income    $ 8,103,549    $ 16,146,294    $ 18,339,359    $ 39,370,266 
Net realized loss    (331,960)    (1,507,632)    (2,584,733)    (994,843) 
Net change in unrealized appreciation/depreciation    (49,773,633)    (19,985,195)    (78,985,745)    (22,744,454) 
Dividends to Preferred Shareholders from net investment income            (6,510,000)    (12,598,505) 
Net increase (decrease) in net assets applicable to Common Shareholders                 
   resulting from operations    (42,002,044)    (5,346,533)    (69,741,119)    3,032,464 
 
     Dividends and Distributions to Common Shareholders From                 
Net investment income    (8,464,356)    (17,002,831)    (13,236,157)    (27,841,571) 
Net realized gain        (65,858)         
Decrease in net assets resulting from dividends and distributions                 
   to Common Shareholders    (8,464,356)    (17,068,689)    (13,236,157)    (27,841,571) 
 
     Capital Share Transactions                 
Reinvestment of common dividends    531,535    1,961,372         
 
     Net Assets Applicable to Common Shareholders                 
Total decrease in net assets applicable to Common Shareholders    (49,934,865)    (20,453,850)    (82,977,276)    (24,809,107) 
Beginning of period    266,913,273    287,367,123    549,415,440    574,224,547 
End of period    $ 216,978,408    $ 266,913,273    $ 466,438,164    $ 549,415,440 
End of period undistributed net investment income    $ 1,305,344    $ 1,666,151    $ 2,046,022    $ 3,452,820 

See Notes to Financial Statements.

20 SEMI-ANNUAL REPORT

NOVEMBER 30, 2008


Financial Highlights                BlackRock MuniAssets Fund, Inc. (MUA) 
 
                                                                                                                                          Six Months
                                                                                                                                               Ended
                                                                                                                                          November 30,
    2008            Year Ended May 31,         
    (Unaudited)         2008         2007               2006        2005         2004 
     Per Share Operating Performance                             
Net asset value, beginning of period    $ 12.79    $ 13.87    $ 13.65    $ 13.40    $ 12.36    $ 11.94 
Net investment income1    0.39    0.78    0.82    0.81        0.81    0.83 
Net realized and unrealized gain (loss)    (2.39)    (1.04)    0.24    0.27        1.04    0.38 
Net increase (decrease) from investment operations    (2.00)    (0.26)    1.06    1.08        1.85    1.21 
Dividends and distributions from:                             
   Net investment income    (0.41)    (0.82)    (0.84)    (0.83)        (0.81)    (0.78) 
   Net realized gain        (0.00)2                    (0.01) 
Total dividends and distributions    (0.41)    (0.82)    (0.84)    (0.83)        (0.81)    (0.79) 
Net asset value, end of period    $ 10.38    $ 12.79    $ 13.87    $ 13.65    $ 13.40    $ 12.36 
Market price, end of period    $ 9.71    $ 13.35    $ 15.29    $ 14.13    $ 13.27    $ 11.38 
 
     Total Investment Return3                             
Based on net asset value    (15.86)%4    (1.90)%    7.72%    8.31%        15.65%    10.74% 
Based on market price    (24.60)%4    (7.12)%    14.71%    13.22%        24.39%    2.22% 
 
     Ratios to Average Net Assets                             
Total expenses after waiver and excluding interest expense and fees5    0.69%6    0.66%    0.68%    0.68%        0.67%    0.67% 
Total expenses after waiver    0.78%6    0.69%    0.68%    0.68%        0.67%    0.67% 
Total expenses    0.78%6    0.70%    0.68%    0.68%        0.67%    0.67% 
Net investment income    6.29%6    5.81%    5.91%    5.97%        6.30%    6.71% 
 
     Supplemental Data                             
Net assets, end of period (000)    $ 216,978    $ 266,913    $ 287,367    $ 280,793    $ 273,382    $ 252,203 
Portfolio turnover    14%    23%    25%    17%        20%    19% 

1 Based on average shares outstanding.
2 Amount is less than $(0.01) .
3 Total investment returns based on market value, which can be significantly greater or lesser than net asset value, may result in substantially different returns. Total investment
returns exclude the effects of sales charges.
4 Aggregate total investment return.
5 Interest expense and fees relate to tender option bond trusts. See Note 1 of the Notes to Financial Statements for details of municipal bonds transferred to tender option
bond trusts.
6 Annualized.

See Notes to Financial Statements.

SEMI-ANNUAL REPORT

NOVEMBER 30, 2008

21


Financial Highlights                         BlackRock Muni Intermediate Duration Fund, Inc. (MUI) 
                                                                                                                                          Six Months
    Ended                    Period 
    November 30,                    August 1, 20031 
            Year Ended May 31,         
    2008                    to May 31, 
    (Unaudited)         2008         2007         2006         2005    2004 
     Per Share Operating Performance                         
Net asset value, beginning of period    $ 14.45    $ 15.10    $ 15.07    $ 15.51    $ 14.52    $ 14.33 
Net investment income    0.482    1.042    1.032    1.042    1.022    0.79 
Net realized and unrealized gain (loss)    (2.15)    (0.63)    0.18    (0.15)    1.15    0.21 
Dividends and distributions to Preferred Shareholders from:                         
   Net investment income    (0.17)    (0.33)    (0.28)    (0.21)    (0.11)    (0.06) 
   Net realized gain            (0.04)    (0.04)    (0.02)     
Net increase (decrease) from investment operations    (1.84)    0.08    0.89    0.64    2.04    0.94 
Dividends and distributions to Common Shareholders from:                         
   Net investment income    (0.35)    (0.73)    (0.74)    (0.84)    (0.86)    (0.65) 
   Net realized gain            (0.12)    (0.23)    (0.19)     
Total dividends and distributions to Common Shareholders    (0.35)    (0.73)    (0.86)    (1.07)    (1.05)    (0.65) 
Capital charges with respect to issuance of Common Shares                        (0.02) 
Capital charges with respect to issuance of Preferred Shares                (0.01)        (0.08) 
Total capital charges with respect to issuance of shares                (0.01)        (0.10) 
Net asset value, end of period    $ 12.26    $ 14.45    $ 15.10    $ 15.07    $ 15.51    $ 14.52 
Market price, end of period    $ 9.99    $ 13.70    $ 14.85    $ 14.52    $ 13.94    $ 13.10 
 
     Total Investment Return3                         
Based on net asset value    (12.59)%4    0.86%    6.14%    4.71%    15.36%    6.09%4 
Based on market price    (24.88)%4    (2.76)%    8.34%    12.25%    14.93%    (8.59%)4 
 
     Ratios to Average Net Assets Applicable to Common Shares                         
Total expenses after waiver and fees paid indirectly and                         
   excluding interest expense and fees5,6    1.01%7    0.90%    0.87%    0.87%    0.84%    0.75%7 
Total expenses after waiver and fees paid indirectly5    1.31%7    1.07%    1.07%    1.00%    0.85%    0.75%7 
Total expenses after waiver and before fees paid indirectly5    1.31%7    1.07%    1.07%    1.00%    0.85%    0.75%7 
Total expenses5    1.51%7    1.30%    1.31%    1.24%    1.07%    1.03%7 
Net investment income5    7.11%7    6.97%    6.71%    6.82%    6.77%    6.51%7 
Dividends to Preferred Shareholders    2.52%7    2.23%    1.80%    1.36%    0.74%    0.48%7 
Net investment income to Common Shareholders    4.59%7    4.74%    4.91%    5.46%    6.03%    6.03%7 
 
     Supplemental Data                         
Net assets applicable to Common Shareholders, end of period (000)    $ 466,438    $ 549,415    $ 574,225    $ 573,034    $ 589,802    $ 552,179 
Preferred Shares outstanding at liquidation preference,                         
   end of period (000)    $ 287,175    $ 320,000    $ 320,000    $ 320,000    $ 285,000    $ 285,000 
Portfolio turnover    6%    14%    12%    49%    54%    70% 
Asset coverage per Preferred Share, end of period8    $ 65,615    $ 67,941    $ 69,875    $ 69,781    $ 76,743    $ 73,441 

1 Commencement of operations.
2 Based on average shares outstanding.
3 Total investment returns based on market value, which can be significantly greater or lesser than net asset value, may result in substantially different returns.
Total investment returns exclude the effects of sales charges.
4 Aggregate total investment return.
5 Do not reflect the effect of dividends to Preferred Shareholders.
6 Interest expense and fees relate to tender option bond trusts. See Note 1 of the Notes to Financial Statements for details of municipal bonds transferred to
tender option bond trusts.
7 Annualized.
8 Prior year amounts have been recalculated to conform with current year presentation.

See Notes to Financial Statements.

22 SEMI-ANNUAL REPORT

NOVEMBER 30, 2008


Notes to Financial Statements (Unaudited)

1. Organization and Significant Accounting Policies:

BlackRock MuniAssets Fund, Inc. (“MuniAssets”) and BlackRock
Muni Intermediate Duration Fund, Inc. (“Muni Intermediate Duration”)
(the “Funds” or individually as the “Fund”), are registered under the
Investment Company Act of 1940, as amended (the “1940 Act”), as
non-diversified, closed-end management investment companies. The
Funds are organized as Maryland corporations. The Funds’ financial
statements are prepared in conformity with accounting principles gener-
ally accepted in the United States of America, which may require the use
of management accruals and estimates. Actual results may differ from
these estimates. The Funds determine and make available for publica-
tion the net asset value of their Common Shares on a daily basis.

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

Valuation of Investments: Municipal investments (including commit-
ments to purchase such investments on a “when-issued” basis) are
valued on the basis of prices provided by dealers or pricing services
selected under the supervision of each Fund’s Board of Directors (the
“Board”). In determining the value of a particular investment, pricing
services may use certain information with respect to transactions in
such investments, quotations from dealers, pricing matrixes, market
transactions in comparable investments and information with respect to
various relationships between investments. Financial futures contracts
traded on exchanges are valued at their last sale price. Short-term secu-
rities are valued at amortized cost.

In the event that application of these methods of valuation results in a
price for an investment which is deemed not to be representative of the
market value of such investment, the investment will be valued by a
method approved by the Board as reflecting fair value (“Fair Value
Assets”). When determining the price for Fair Value Assets, the invest-
ment advisor and/or the sub-advisor seeks to determine the price that
the Funds might reasonably expect to receive from the current sale of
that asset in an arm’s-length transaction. Fair value determinations shall
be based upon all available factors that the investment advisor and/or
the sub-advisor deems relevant. The pricing of all Fair Value Assets is
subsequently reported to the Board or a committee thereof.

Derivative Financial Instruments: The Funds may engage in various
portfolio investment strategies both to increase the return of the Funds
and to hedge, or protect, their exposure to interest rate movements
and movements in the securities markets. Losses may arise if the value
of the contract decreases due to an unfavorable change in the price of
the underlying security or if the counterparty does not perform under
the contract.

Financial futures contracts — The Funds may purchase or sell finan-
cial futures contracts and options on financial futures contracts for
investment purposes or to manage their interest rate risk. Futures are

contracts for delayed delivery of securities at a specific future date
and at a specific price or yield. Pursuant to the contract, the Funds
agree to receive from or pay to the broker an amount of cash equal
to the daily fluctuation in value of the contract. Such receipts or pay-
ments are known as margin variation and are recognized by the Funds
as unrealized gains or losses. When the contract is closed, the Funds
record a realized gain or loss equal to the difference between the
value of the contract at the time it was opened and the value at the
time it was closed. The use of futures transactions involves the risk
of an imperfect correlation in the movements in the price of futures
contracts, interest rates and the underlying assets, and the possible
inability of counterparties to meet the terms of their contracts.

Forward Commitments and When-Issued Delayed Delivery Securities:
The Funds may purchase securities on a when-issued basis and may
purchase or sell securities on a forward commitment basis. Settlement
of such transactions normally occurs within a month or more after the
purchase or sale commitment is made. The Funds may purchase securi-
ties under such conditions only with the intention of actually acquiring
them, but may enter into a separate agreement to sell the securities
before the settlement date. Since the value of securities purchased may
fluctuate prior to settlement, the Funds may be required to pay more at
settlement than the security is worth. In addition, the purchaser is not
entitled to any of the interest earned prior to settlement. When purchas-
ing a security on a delayed-delivery basis, a Fund assumes the rights
and risks of ownership of the security, including the risk of price and
yield fluctuations.

Municipal Bonds Transferred to Tender Option Bond Trusts: The Funds
may leverage their assets through the use of tender option bond trusts
(“TOBs”). A TOB is established by a third party sponsor forming a special
purpose entity, into which one or more funds, or an agent on behalf of
the funds, transfers municipal securities. Other funds managed by the
investment advisor may also contribute municipal securities to a TOB
into which each Fund has contributed securities. A TOB typically issues
two classes of beneficial interests: short-term floating rate certificates,
which are sold to third party investors, and residual certificates (“TOB
Residuals”), which are generally issued to the participating funds that
made the transfer. The TOB Residuals held by a Fund include the right of
the Fund (1) to cause the holders of a proportional share of the floating
rate certificates to tender their certificates at par, and (2) to transfer,
within seven days, a corresponding share of the municipal securities
from the TOB to the Fund. The cash received by the TOB from the sale of
the short-term floating rate certificates, less transaction expenses, is
paid to the Fund, which typically invest the cash in additional municipal
securities. Each Fund’s transfer of the municipal securities to a TOB is
accounted for as a secured borrowing, therefore the municipal securities
deposited into a TOB are presented in the Funds’ Schedules of Invest-
ments and the proceeds from the transaction are reported as a liability
for trust certificates.

SEMI-ANNUAL REPORT NOVEMBER 30, 2008 23


Notes to Financial Statements (continued)

Interest income from the underlying securities is recorded by the Funds
on an accrual basis. Interest expense incurred on the secured borrowing
and other expenses related to remarketing, administration and trustee
services to a TOB are reported as expenses of the Funds. The floating
rate certificates have interest rates that generally reset weekly and their
holders have the option to tender certificates to the TOB for redemption
at par at each reset date. At November 30, 2008, the aggregate value of
the underlying municipal securities transferred to TOBs, the related liabil-
ity for trust certificates and the range of interest rates were as follows:

Underlying
Municipal
    Securities    Liability for    Range of 
    Transferred    Trust    Interest 
    to TOBs    Certificates    Rates 
MuniAssets    $ 6,906,626    $ 4,435,000    2.546% 
Muni Intermediate Duration    $90,113,443    $53,282,804    2.499% — 
            2.978% 

Financial transactions executed through TOBs generally will underperform
the market for fixed rate municipal bonds when short-term interest rates
rise, but tend to outperform the market for fixed rate bonds when short-
term interest rates decline or remain relatively stable. Should short-term
interest rates rise, each Fund’s investment in TOBs likely will adversely
affect each Fund’s net investment income and dividends to Common
Shareholders. Fluctuations in the market value of municipal securities
deposited into the TOB may adversely affect each Fund’s net asset
values per share.

Zero-Coupon Bonds: The Funds may invest in zero-coupon bonds,
which are normally issued at a significant discount from face value and
do not provide for periodic interest payments. Zero-coupon bonds may
experience greater volatility in market value than similar maturity debt
obligations which provide for regular interest payments.

Segregation and Collateralization: In cases in which the 1940 Act and
the interpretive positions of the Securities and Exchange Commission
(“SEC”) require that the Funds segregate assets in connection with
certain investments (e.g., financial futures contracts), each Fund will,
consistent with certain interpretative letters issued by the SEC, designate
on its books and records cash or other liquid securities having a market
value at least equal to the amount that would otherwise be required
to be physically segregated. Furthermore, based on requirements and
agreements with certain exchanges and third party broker-dealers, the
Funds may also be required to deliver or deposit securities as collateral
for certain investments (e.g., financial futures contracts).

Investment Transactions and Investment Income: Investment trans -
actions are recorded on the dates the transactions are entered into
(the trade dates). Realized gains and losses on security transactions

are determined on the identified cost basis. Dividend income is
recorded on the ex-dividend dates. Interest income is recognized on
the accrual method. Each Fund amortizes all premiums and discounts
on debt securities.

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. Dividends and distributions to
Preferred Shareholders are accrued and determined as described
in Note 4.

Income Taxes: It is each Fund’s policy to comply with the requirements
of the Internal Revenue Code applicable to regulated investment com-
panies and to distribute substantially all of its taxable income to its
shareholders. Therefore, no federal income tax provision is required.

Each Fund files U.S. federal and various state and local tax returns. No
income tax returns are currently under examination. The statute of limita-
tions on each Fund’s U.S. federal tax returns remains open for the years
ended May 31, 2005 through May 31, 2007. The statutes of limitations
on each Fund’s state and local tax returns may remain open for an addi-
tional year depending upon the jurisdiction.

Recent Accounting Pronouncement: In March 2008, Statement of
Financial Accounting Standards No. 161, “Disclosures about Derivative
Instruments and Hedging Activities — an amendment of FASB Statement
No. 133” (“FAS 161”), was issued. FAS 161 is intended to improve
financial reporting for derivative instruments by requiring enhanced
disclosure that enables investors to understand how and why an entity
uses derivatives, how derivatives are accounted for, and how derivative
instruments affect an entity’s results of operations and financial posi-
tion. FAS 161 is effective for financial statements issued for fiscal years
and interim periods beginning after November 15, 2008. The impact
on each Fund’s financial statement disclosures, if any, is currently
being assessed.

Deferred Compensation and BlackRock Closed-End Share Equivalent
Investment Plan: Under the deferred compensation plan approved by
each Fund’s Board, non-interested Directors (“Independent Directors”)
defer a portion of their annual complex-wide compensation. Deferred
amounts earn an approximate return as though equivalent dollar
amounts have been invested in common shares of other certain
BlackRock Closed-End Funds selected by the Independent Directors.
This has approximately the same economic effect for the Independent
Directors as if the Independent Directors had invested the deferred
amounts directly in other certain BlackRock Closed-End Funds.

The deferred compensation plan is not funded and obligations there-
under represent general unsecured claims against the general assets of

24 SEMI-ANNUAL REPORT

NOVEMBER 30, 2008


Notes to Financial Statements (continued)

the Funds. Each Fund may, however, elect to invest in Common Shares of
other certain BlackRock Closed-End Funds selected by the Independent
Directors in order to match its deferred compensation obligations.
Investments to cover each Fund’s deferred compensation liability are
included in other assets on the Statements of Assets and Liabilities.
Dividends and distributions from the BlackRock Closed-End Fund
investments under the plan are included in income — affiliated on
the Statements of Operations.

Other: Expenses directly related to each 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 appro-
priate methods.

2. Investment Advisory Agreement and Other Transactions
with Affiliates:

Each Fund has entered into an Investment Advisory Agreement with
BlackRock Advisors, LLC (the “Advisor”), an indirect, wholly owned sub-
sidiary of BlackRock, Inc., to provide investment advisory and administra-
tion services. Merrill Lynch & Co., Inc. (“Merrill Lynch”), a wholly owned
subsidiary of Bank of America Corporation (“BAC”), and The PNC Financial
Services Group, Inc. are the largest stockholders of BlackRock, Inc.

The Advisor is responsible for the management of each Fund’s portfolio
and provides the necessary personnel, facilities, equipment and certain
other services necessary to the operations of each Fund. For such serv-
ices, each Fund pays the Advisor a monthly fee at an annual rate of
0.55% of the respective Fund’s average daily net assets. Average daily
net assets is the average daily value of the respective Fund’s total assets
minus the sum of its accrued liabilities.

The Advisor has contractually agreed to waive a portion of its fee during
the first seven years of Muni Intermediate Duration’s operations ending
July 31, 2010 as follows:

    Fee Waiver 
    (As a Percentage 
    of Average Daily 
    Net Assets) 
Years 1 through 5    0.15% 
Year 6    0.10% 
Year 7    0.05% 
Year 8 and thereafter    0.00% 

The Advisor has not agreed to waive any portion of its fee beyond
July 31, 2010.

This amount is included in fees waived by advisor on the Statements of
Operations. For the six months ended November 30, 2008, the amount
was as follows:

    Fees Waived 
    by Advisor 
Muni Intermediate Duration    $ 427,483 

The Advisor has agreed to waive its advisory fees by the amount of invest-
ment advisory fees each Fund pays to the Advisor indirectly through its
investment in affiliated money market funds. These amounts are included
in fees waived by advisor on the Statements of Operations. For the six
months ended November 30, 2008, the amounts were as follows:

    Fees Waived 
    by Advisor 
MuniAssets    $ 5,763 
Muni Intermediate Duration    $ 80,975 

The Advisor has entered into separate sub-advisory agreements with
BlackRock Investment Management, LLC (“BIM”), an affiliate of the
Advisor, with respect to each Fund, under which the Advisor pays BIM for
services it provides, a monthly fee that is a percentage of the investment
advisory fee paid by each Fund to the Advisor.

For the six months ended November 30, 2008, the Funds reimbursed
the Advisor for certain accounting services. The reimbursements, which
are included in accounting services on the Statements of Operations,
were as follows:

    Reimbursements 
    to Advisor 
MuniAssets    $ 2,246 
Muni Intermediate Duration    $ 6,487 

Certain officers and/or directors of the Funds are officers and/or
directors of BlackRock, Inc. or its affiliates. The Funds reimburse the
Advisor for compensation paid to the Funds’ Chief Compliance Officer.

3. Investments:

Purchases and sales of investments, excluding short-term securities,
for the six months ended November 30, 2008 were as follows:

    Total    Total 
    Purchases    Sales 
MuniAssets    $39,877,596    $33,007,587 
Muni Intermediate Duration    $51,078,238    $68,255,644 

SEMI-ANNUAL REPORT

NOVEMBER 30, 2008

25


Notes to Financial Statements (continued)

4. Capital Share Transactions:

Common Shares

Each Fund is authorized to issue 200,000,000 shares, including
Preferred Shares for Muni Intermediate Duration, par value $0.10 per
share, all of which were initially classified as Common Shares. The Board
is authorized, however, to reclassify any unissued Common Shares with-
out approval of the holders of Common Shares.

Shares issued and outstanding increased by 42,069 for the six months
ended November 30, 2008 and 146,172 for the year ended May 31,
2008 as a result of dividend reinvestment for MuniAssets and remained
constant for Muni Intermediate Duration.

Preferred Shares of Muni Intermediate Duration

The Preferred Shares are redeemable at the option of the Fund, in whole
or in part, on any dividend payment date at $25,000 per share plus any
accumulated or unpaid dividends whether or not declared. The Preferred
Shares are also subject to mandatory redemption at $25,000 per share
plus any accumulated or unpaid dividends, whether or not declared, if
certain requirements relating to the composition of the assets and liabil-
ities of the Fund, as set forth in the Fund’s Articles Supplementary, are
not satisfied.

The holders of Preferred Shares have voting rights equal to the holders
of Common Shares (one vote per share) and will vote together with the
holders of Common Shares (one vote per share) as a single class.
However, the holders of Preferred Shares, voting as a separate class, are
also entitled to elect two Directors for the Fund. In addition, the 1940
Act requires that along with the approval of the holders of a majority of
any outstanding Preferred Shares, voting separately as a class, would be
required to (a) adopt any plan of reorganization that would adversely
affect the Preferred Shares (b) change the Fund’s sub classification as a
closed-end investment company or change its fundamental investment
restrictions or (c) change its business so as to cease to be an invest-
ment company.

The Fund had the following series of Preferred Shares outstanding and
effective yields at November 30, 2008:

Series    Shares    Yield 
M7    1,795    2.526% 
T7    2,423    2.748% 
W7    1,795    2.485% 
TH7    2,423    2.485% 
F7    1,795    2.346% 
TH28    1,256    2.554% 

Dividends on seven-day Preferred Shares are cumulative at a rate, which
is reset every seven days based on the results of an auction. Dividends
on 28 day Preferred Shares are cumulative at a rate which is reset every
28 days based on the results of an auction. If the Preferred Shares fail

to clear the auction on an auction date, the Fund is required to pay
the maximum applicable rate on the Preferred Shares to holders of
such shares for each successive dividend period until such time as the
shares are successfully auctioned. The maximum applicable rate on the
Preferred Shares is the higher of 110% of the Telerate/BBA LIBOR or
110% of 90% of the Kenny S&P 30-day High Grade Index rate divided
by 1.00 minus the marginal tax rate. The low, high and average dividend
rates on the Preferred Shares of the Fund for the six months ended
November 30, 2008 were as follows:

Series    Low    High    Average 
M7    2.526%    10.377%    4.409% 
T7    2.568%    11.415%    4.393% 
W7    2.485%    12.523%    4.416% 
TH7    2.485%    12.246%    4.411% 
F7    2.346%    11.762%    4.400% 
TH28    2.554%    12.246%    5.063% 

Since February 13, 2008, the Preferred Shares of the Fund failed to
clear any of its auctions. As a result, the Preferred Shares dividend rates
were reset to the maximum applicable rate, which ranged from 2.346%
to 12.523% . A failed auction is not an event of default for the Fund
but has a negative impact on the liquidity of Preferred Shares. A failed
auction occurs when there are more sellers of a fund’s auction rate
preferred shares than buyers. It is impossible to predict how long this
imbalance will last. A successful auction for the Fund’s Preferred Shares
may not occur for some time, if ever, and even if liquidity does resume,
holders of Preferred Shares may not have the ability to sell the Preferred
Shares at their liquidation preference.

The Fund may not declare dividends or make other distributions on
Common Shares or purchase any such shares if, at the time of the dec-
laration, distribution or purchase, asset coverage with respect to the out-
standing Preferred Shares is less than 200%.

The Fund pays commissions to certain broker-dealers at the end of each
auction at an annual rate of 0.25%, calculated on the aggregate princi-
pal amount. For the six months ended November 30, 2008, Merrill
Lynch, Pierce, Fenner & Smith Incorporated, a wholly owned subsidiary
of Merrill Lynch, earned commissions of $248,483.

On June 2, 2008, the Fund announced the following redemptions of
Preferred Shares at a price of $25,000 per share plus any accrued and
unpaid dividends through the redemption date:

    Redemption    Shares    Aggregate 
Series    Date    Redeemed    Principal 
M7    6/24/2008    205    $5,125,000 
T7    6/25/2008    277    $6,925,000 
W7    6/26/2008    205    $5,125,000 
TH7    6/27/2008    277    $6,925,000 
F7    6/23/2008    205    $5,125,000 
TH28    7/07/2008    144    $3,600,000 

26 SEMI-ANNUAL REPORT

NOVEMBER 30, 2008


Notes to Financial Statements (concluded)

The Fund financed the Preferred Share redemptions with cash received
from TOB transactions.

Preferred Shares issued and outstanding for the year ended May 31,
2008 remained constant.

5. Capital Loss Carryforward:

As of May 31, 2008, the Funds had capital loss carryforwards available to
offset future realized capital gains through the indicated year of expiration:

        Muni Intermediate 
Expires May 31,    MuniAssets    Duration 
2009    $ 3,487,083     
2010    2,260,830     
2011    7,452,325     
2012    5,486,273     
2013    3,762,613     
2015    5,065,527    $ 334,473 
2016    527,783    611,323 
Total    $28,042,434    $ 945,796 

6. Concentration Risk:

Each Fund’s investments are concentrated in certain states, which may
be affected by adverse financial, social, environmental, economic, regu-
latory and political factors.

Many municipalities insure repayment of their bonds, which reduces the
risk of loss due to issuer default. The market value of these bonds may
fluctuate for other reasons, including market perception of the value of
such insurance, and there is no guarantee that the insurer will meet
its obligations.

7. Restatement Information:

Subsequent to the initial issuance of its May 31, 2006 financial state-
ments, Muni Intermediate Duration determined that the criteria for sale
accounting had not been met for certain transfers of municipal bonds,
and that these transfers should have been accounted for as secured
borrowings rather than as sales. As a result, certain financial highlights
for the year ended May 31, 2005 have been restated to give effect to
recording the transfers of the municipal bonds as secured borrowings,
including recording interest on the bonds as interest income and interest
on the secured borrowings as interest expense.

Muni Intermediate Duration         
Financial Highlights         
For the Year Ended May 31, 2005         
    2005 
    Previously     
    Reported    Restated 
Total expenses, net of waiver***    0.84%    0.85% 
Portfolio turnover    54.55%    54% 
*** Do not reflect the effect of dividends to Preferred Shareholders.     

8. Subsequent Events:

Each Fund paid a net investment income dividend to Common
Shareholders on December 31, 2008 to shareholders of record on
December 15, 2008 in the following amounts per share:

    Per Share 
    Amount 
MuniAssets    $0.0675 
Muni Intermediate Duration    $0.0580 

The dividends declared on Preferred Shares for Muni Intermediate
Duration for the period December 1, 2008 to December 31, 2008 were
as follows:

    Dividends 
Series    Declared 
M7    $ 84,123 
T7    $115,576 
W7    $ 87,990 
TH7    $117,311 
F7    $ 84,330 
TH28    $ 63,607 

On January 1, 2009, BAC announced that it had completed its acquisi-
tion of Merrill Lynch, one of the largest stockholders of BlackRock, Inc.

In December 2008, commissions paid to broker-dealers on preferred
shares that experience a failed auction were reduced to 0.15% on the
aggregate principal amount. Muni Intermediate Duration will continue to
pay commissions of 0.25% on the aggregate principal amount of all
shares that successfully clear their auctions.

SEMI-ANNUAL REPORT

NOVEMBER 30, 2008

27


Officers and Directors

Richard E. Cavanagh, Chairman of the Board and Director
Karen . Robards, Vice Chair of the Board, Chair of the
Audit Committee and Director
G. Nicholas Beckwith, III, Director
Richard S. Davis, Director
Kent Dixon, Director
Frank J. Fabozzi, Director
Kathleen F. Feldstein, Director
James T. Flynn, Director
Henry Gabbay, Director
Jerrold B. Harris, Director
R. Glenn Hubbard, Director
W. Carl Kester, Director
Robert S. Salomon, Jr., Director
Donald C. Burke, Fund President and Chief Executive Officer
Anne F. Ackerley, Vice President
Neal J. Andrews, Chief Financial Officer
Jay M. Fife, Treasurer
Brian P. Kindelan, Chief Compliance Officer of the Funds
Howard B. Surloff, Secretary

Custodian
The Bank of New York Mellon
New York, NY 10286

Transfer Agent
Common Shares and
Preferred Shares
BNY Mellon Shareowner Services
Jersey City, NJ 07310

Accounting Agent
State Street Bank and
Trust Company
Princeton, NJ 08540

Independent Registered Public
Accounting Firm
Deloitte & Touche LLP
Princeton, NJ 08540

Legal Counsel
Skadden, Arps, Slate,
Meagher & Flom LLP
New York, NY 10036

Effective January 1, 2009, Robert S. Salomon, Jr. retired as Director
of the Funds. The Board of Directors wishes Mr. Salomon well in
his retirement.

  28 SEMI-ANNUAL REPORT NOVEMBER 30, 2008


Additional Information

Proxy Results

The Annual Meeting of Shareholders was held on September 12, 2008 for shareholders of record on July 14, 2008, to elect director nominees
of each Fund:

Approved the Class I Directors as follows:

    G. Nicholas Beckwith, III    Kent Dixon    R. Glenn Hubbard 
        Votes        Votes        Votes 
    Votes For    Withheld    Votes For    Withheld    Votes For    Withheld 
BlackRock MuniAssets Fund, Inc.    18,786,839     577,002    18,787,515     576,326    18,782,035               581,806 
    W. Carl Kester    Robert S. Salomon, Jr.         
        Votes        Votes         
    Votes For    Withheld    Votes For    Withheld         
    18,789,906     573,935    18,778,252     585,589         
 
Approved the Directors as follows:                         
    G. Nicholas Beckwith, III    Kent Dixon    R. Glenn Hubbard 
        Votes        Votes        Votes 
    Votes For    Withheld    Votes For    Withheld    Votes For    Withheld 
BlackRock Muni Intermediate Duration Fund, Inc.    34,923,127    1,290,867    34,913,382    1,300,612    34,902,329           1,311,665 
 
    W. Carl Kester    Robert S. Salomon, Jr.    Richard S. Davis 
        Votes        Votes        Votes 
    Votes For    Withheld    Votes For    Withheld    Votes For    Withheld 
    8,5971    1,3091    34,916,437    1,297,557    34,926,066           1.287,928 
 
    Frank J. Fabozzi    James T. Flynn    Karen P. Robards 
        Votes        Votes        Votes 
    Votes For    Withheld    Votes For    Withheld    Votes For    Withheld 
    8,5971    1,3091    34,918,851    1,295,143    34,926,469           1,287,525 
 
    Richard Cavanagh    Kathleen F. Feldstein    Henry Gabbay 
        Votes        Votes        Votes 
    Votes For    Withheld    Votes For    Withheld    Votes For    Withheld 
    34,923,666    1,290,328    34,920,521    1,293,473    34,929,150           1,284,844 
 
    Jerrold B. Harris                 
        Votes                 
    Votes For    Withheld                 
    34,920,251    1,293,743                 
 
   1 Voted on by holders of Preferred Shares only.                         

SEMI-ANNUAL REPORT NOVEMBER 30, 2008 29


Additional Information (continued)

Dividend Policy

The Funds’ dividend policy is to distribute all or a portion of their net
investment income to their shareholders on a monthly basis. In order to
provide shareholders with a more stable level of dividend distributions,
the Funds may at times pay out less than the entire amount of net
investment income earned in any particular month and may at times
in any particular month pay out such accumulated but undistributed
income in addition to net investment income earned in that month.

As a result, the dividends paid by the Funds for any particular month
may be more or less than the amount of net investment income earned
by the Funds during such month. The Funds’ current accumulated
but undistributed net investment income, if any, is disclosed in the
Statements of Assets and Liabilities, which comprises part of the
financial information included in this report.

Availability of Quarterly Schedule of Investments

The Funds file their complete schedule of portfolio holdings with
the SEC for the first and third quarters of each fiscal year on
Form N-Q. The Funds’ 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, DC. Information on the
operation of the Public Reference Room may be obtained by calling
(800) SEC-0330. The Funds’ Forms N-Q may also be obtained upon
request and without charge by calling (800) 441-7762.

Electronic Delivery

Electronic copies of most financial reports are available on the Funds’
websites or shareholders can sign up for e-mail notifications of quarterly
statements, annual and semi-annual reports by enrolling in the Funds’
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.

General Information

The Funds will mail only one copy of shareholder documents, including
annual and semi-annual reports and proxy statements, to shareholders
with multiple accounts at the same address. This practice is commonly
called “householding” and it is intended to reduce expenses and elimi-
nate 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 Funds at (800) 441-7762.

Quarterly performance, semi-annual and annual reports and other
information regarding the Funds may be found on BlackRock’s website,
which can be accessed at http://www.blackrock.com. This reference
to BlackRock’s website is intended to allow investors public access to
information regarding the Funds and does not, and is not intended to,
incorporate BlackRock’s website into this report.

30 SEMI-ANNUAL REPORT

NOVEMBER 30, 2008


Additional Information (concluded)

Articles Supplementary

Effective September 13, 2008, following approval by Muni Intermediate
Duration’s Board and the applicable rating agencies, the Board amended
the terms of Muni Intermediate Duration’s Preferred Shares in order to
allow Muni Intermediate Duration to enter into TOB transactions, the
proceeds of which were used to redeem a portion of Muni Intermediate
Duration’s Preferred Shares. Accordingly, the definition of Inverse Floaters

was amended to incorporate Muni Intermediate Duration’s permissable
ratio of floating rate instruments into inverse floating rate instruments.
Additionally, conforming changes and certain formula modifications con-
cerning inverse floaters were made to the definitions of Moody’s Discount
Factor and S&P Discount Factor, as applicable, to integrate Muni Inter-
mediate Duration’s investments in TOBs into applicable calculations.

BlackRock Privacy Principles

BlackRock is committed to maintaining the privacy of its current and
former 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.

SEMI-ANNUAL REPORT

NOVEMBER 30, 2008

31



This report is transmitted to shareholders only. It is not a prospectus.
Past performance results shown in this report should not be con-
sidered a representation of future performance. BlackRock Muni
Intermediate Duration Fund, Inc. has leveraged its Common Shares,
which creates risks for Common Shareholders, including the likeli-
hood of greater volatility of net asset value and market price of
the Common Shares, and the risk that fluctuations in the short-term
dividend rates of the Preferred Shares, currently set at the maximum
reset rate as a result of failed auctions, may affect the yield to
Common Shareholders. Statements and other information herein
are as dated and are subject to change.

A description of the policies and procedures that the Funds use
to determine how to vote proxies relating to portfolio securities
is available (1) without charge, upon request, by calling toll-
free (800) 441-7762; (2) at www.blackrock.com; and (3)
on the Securities and Exchange Commission’s website at
http://www.sec.gov. Information about how the Funds voted
proxies relating to securities held in the Funds’ portfolio during
the most recent 12-month period ended June 30 is available
upon request and without charge (1) at www.blackrock.com or
by calling (800) 441-7762 and (2) on the Securities and
Exchange Commission’s website at http://www.sec.gov.

BlackRock MuniAssets Fund, Inc.

BlackRock Muni Intermediate Duration Fund, Inc.

100 Bellevue Parkway

Wilmington, DE 19809

#MIDMA-11/08


Item 2 – Code of Ethics – Not Applicable to this semi-annual report

Item 3 – Audit Committee Financial Expert – Not Applicable to this semi-annual report

Item 4 – Principal Accountant Fees and Services – Not Applicable to this semi-annual report

Item 5 – Audit Committee of Listed Registrants – Not Applicable to this semi-annual report

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 to this semi-annual report

Item 8 – Portfolio Managers of Closed-End Management Investment Companies – Not Applicable to
this semi-annual report

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 – The registrant’s Nominating and
Governance Committee will consider nominees to the board of directors recommended by
shareholders when a vacancy becomes available. Shareholders who wish to recommend a
nominee should send nominations that include biographical information and set forth the
qualifications of the proposed nominee to the registrant’s Secretary. 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 13(a)-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 last fiscal half-year
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 – Not Applicable to this semi-annual report

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.

BlackRock MuniAssets Fund, Inc.

By: /s/ Donald C. Burke
Donald C. Burke
Chief Executive Officer of
BlackRock MuniAssets Fund, Inc.

Date: January 20, 2009

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/ Donald C. Burke
Donald C. Burke
Chief Executive Officer (principal executive officer) of
BlackRock MuniAssets Fund, Inc.

Date: January 20, 2009

By: /s/ Neal J. Andrews
Neal J. Andrews
Chief Financial Officer (principal financial officer) of
BlackRock MuniAssets Fund, Inc.

Date: January 20, 2009