Blackrock Muniholdings Investment Quality Fund (MFL) N-CSRS Certified semi-annual shareholder report (management investment company)

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 811-08349

Name of Fund: BlackRock MuniHoldings Insured Investment Fund (MFL)

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: Anne F. Ackerley, Chief Executive Officer, BlackRock MuniHoldings Insured Investment Fund, 55 East 52^nd Street, New York, NY 10055.

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

Date of fiscal year end: 08/31/2010

Date of reporting period: 02/28/2010

Item 1 – Report to Stockholders

Semi-Annual Report
FEBRUARY 28, 2010 | (UNAUDITED)
BlackRock Insured Municipal Income Trust (BYM)
BlackRock Insured Municipal Income Investment Trust (BAF)
BlackRock Municipal Bond Trust (BBK)
BlackRock Municipal Bond Investment Trust (BIE)
BlackRock Municipal Income Trust II (BLE)
BlackRock MuniHoldings Insured Investment Fund (MFL)
BlackRock MuniVest Fund, Inc. (MVF)

NOT FDIC INSURED
MAY LOSE VALUE
NO BANK GUARANTEE

Table of Contents

	Page
Dear Shareholder	3
Semi-Annual Report:
Trust Summaries	4
The Benefits and Risks of Leveraging	11
Derivative Financial Instruments	11
Financial Statements:
Schedules of Investments	12
Statements of Assets and Liabilities	39
Statements of Operations	40
Statements of Changes in Net Assets	41
Statements of Cash Flows	44
Financial Highlights	45
Notes to Financial Statements	52
Officers and Trustees	59
Additional Information	60

2 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

Dear Shareholder

The past year marked a pivotal turning point for global markets as the Great Recession that started in December 2007 began to recede and give way to recovery. The dramatic about-face could be attributed to a confluence of factors, most notably the extraordinary policy actions of global governments and central banks, a resurgence in corporate profits and growing signs of stability and healing in world economies.

After reaching a trough in early March 2009, stocks galloped higher as investors were lured back into the markets by depressed valuations, desire for higher yields and increasing confidence that all-out financial disaster had been averted. The result was a powerful upswing in global equities and other higher-risk assets through the end of 2009. More recently, the combination of mixed economic data, lingering deflation issues (especially in Europe) and proposed fees and levies on banks dampened investor conviction, resulting in a several-week bout of profit-taking. The selloff had a more pronounced negative effect on international and emerging market equities due primarily to concerns of higher interest rates in Asia and negative headlines out of Europe, particularly in Greece.

Generally speaking, investors’ renewed affinity for risk was notable in the fixed income markets as well, where non-Treasury assets made a robust recovery. One of the major themes in 2009 was the reversal of the flight-to-quality trade. High yield, one of the most battered areas during the financial crisis, emerged as the strongest-performing fixed income sector in both the taxable and tax-exempt space. Despite weak fundamentals, the municipal market produced solid returns as technical conditions remained supportive of the asset class. Municipal bond mutual funds enjoyed strong inflows and tax-exempt issuance remained low thanks to the ever-increasing popularity of the Build America Bond program. Nevertheless, state and local fiscal woes and bankruptcy fears remain firmly in the spotlight, and bear close monitoring.

At the same time, yields on money market securities declined throughout the reporting period and remain near all-time lows, with the Federal Open Market Committee reiterating that economic circumstances are likely to necessitate an accommodative interest rate stance for an “extended period.” Investor assets in money market funds declined from the peak registered in early 2009, but remain above levels registered prior to the financial crisis that began in 2007.

Against this backdrop, the major market averages posted the following returns:

Total Returns as of February 28, 2010	6-month		12-month
US equities (S&P 500 Index)	9.32	%	53.62	%
Small cap US equities (Russell 2000 Index)	10.59		63.95
International equities (MSCI Europe, Australasia, Far East Index)	0.72		54.58
3-month Treasury bill (BofA Merrill Lynch 3-Month Treasury Bill Index)	0.07		0.20
US Treasury securities (BofA Merrill Lynch 10-Year US Treasury Index)	0.07		(1.54	)
Taxable fixed income (Barclays Capital US Aggregate Bond Index)	3.19		9.32
Tax-exempt fixed income (Barclays Capital Municipal Bond Index)	4.13		9.98
High yield bonds (Barclays Capital US Corporate High Yield 2% Issuer Capped Index)	13.86		55.20

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

The market continues to show signs of improvement, but questions about the strength and sustainability of the recovery abound. Through periods of uncertainty, as ever, BlackRock’s full resources are dedicated to the management of our clients’ assets. For additional market perspective and investment insight, visit www.blackrock.com/shareholdermagazine, where you’ll find the most recent issue of our award-winning Shareholder^® magazine, as well as its quarterly companion newsletter, Shareholder Perspectives. As always, we thank you for entrusting BlackRock with your investments, and we look forward to your continued partnership in the months and years ahead.

Sincerely,

Rob Kapito
President, BlackRock Advisors, LLC

THIS PAGE NOT PART OF YOUR FUND REPORT 3

Trust Summary as of February 28, 2010	BlackRock Insured Municipal Income Trust
Investment Objective

BlackRock Insured Municipal Income Trust (BYM) (the “Trust”) seeks to provide high current income exempt from regular federal income taxes. The Trust will invest at least 80% of its managed assets in municipal obligations that are insured as to the timely payment of both principal and interest.

          No assurance can be given that the Trust’s investment objective will be achieved.

Performance

For the six months ended February 28, 2010, the Trust returned 3.09% based on market price and 6.21% based on net asset value (“NAV”). For the same period, the closed-end Lipper Insured Municipal Debt Funds (Leveraged) category posted an average return of 8.13% on a market price basis and 6.47% on a NAV basis. All returns reflect reinvestment of dividends. The Trust moved from a premium to NAV to a discount, which accounts for the difference between performance based on price and performance based on NAV. The Trust’s constructive duration during a period in which yields fell (prices increased) contributed to performance. Exposure to the long end of the yield curve also was favorable as the yield curve flattened. In addition, credit spreads generally tightened during the period, which was a positive due to our exposure to insured bonds with weaker underlying credits. On the other hand, the Trust’s exposure to zero-coupon holdings detracted from results as these types of bonds generally underperformed during the period. Low exposure to the education sector also was a negative as that sector performed well. Lastly, exposure to municipal credits in California hindered performance as bonds sold by issuers in that state generally under-performed other states.

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.

Trust Information

Symbol on New York Stock Exchange (“NYSE”)	BYM
Initial Offering Date	October 31, 2002
Yield on Closing Market Price as of February 28, 2010 ($13.70)1	6.00%
Tax Equivalent Yield2	9.23%
Current Monthly Distribution per Common Share3	$0.0685
Current Annualized Distribution per Common Share3	$0.8220
Leverage as of February 28, 20104	35%

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	A change in the distribution rate was declared on March 1, 2010. The Monthly Distribution per Common Share was increased to $0.072. The Yield on Closing Market Price, Current Monthly Distribution per Common Share and Current Annualized Distribution per Common Share do not reflect the new distribution rate. The new distribution rate is not constant and is subject to change in the future.
4	Represents Auction Market Preferred Shares (“Preferred Shares”) and tender option bond trusts (“TOBs”) as a percentage of total managed assets, which is the total assets of the Trust, including any assets attributable to Preferred Shares and TOBs, minus the sum of accrued liabilities. For a discussion of leveraging techniques utilized by the Trust, please see The Benefits and Risks of Leveraging on page 11.

The table below summarizes the changes in the Trust’s market price and NAV per share:

	2/28/10		8/31/09		Change			High		Low
Market Price	$	13.70	$	13.69		0.07	%	$	14.48	$	12.78
Net Asset Value	$	13.97	$	13.55		3.10	%	$	14.62	$	13.54

The following charts show the sector and credit quality allocations of the Trust’s long-term investments:

Sector Allocations

	2/28/10		8/31/09
Utilities	25	%	25	%
Transportation	24		25
County/City/Special District/School District	21		19
State	14		15
Health	7		7
Tobacco	6		6
Education	2		2
Housing	1		1

Credit Quality Allocations⁵

	2/28/10		8/31/09
AAA/Aaa	56	%	56	%
AA/Aa	21		19
A	13		15
BBB/Baa	8		8
Not Rated6	2		2

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 February 28, 2010 and August 31, 2009, the market value of these securities was $10,733,100 representing 2% and $10,859,100 representing 2%, respectively, of the Trust’s long-term investments.

4 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

Trust Summary as of February 28, 2010 BlackRock Insured Municipal Income Investment Trust

Investment Objective

BlackRock Insured Municipal Income Investment Trust (BAF) (the “Trust”) seeks to provide current income exempt from regular federal income taxes, including the alternative minimum tax and Florida intangible personal property tax. The Trust will invest at least 80% of its managed assets in municipal obligations that are insured as to the timely payment of both principal and interest. The Trust may invest in municipal obligations regardless of geographic location.

          No assurance can be given that the Trust’s investment objective will be achieved.

Performance

For the six months ended February 28, 2010, the Trust returned 10.90% based on market price and 4.89% based on NAV. For the same period, the closed-end Lipper Insured Municipal Debt Funds (Leveraged) category posted an average return of 8.13% on a market price basis and 6.47% on a NAV basis. All returns reflect reinvestment of dividends. The Trust’s discount to NAV, which narrowed during the period, accounts for the difference between performance based on price and performance based on NAV. The Trust held a higher concentration in health care and housing bonds with maturities of 20 years and longer, which benefited performance as the municipal yield curve flattened during the last six months. On the downside, the lack of availability in the national insured market has made it difficult to fully transition the portfolio away from its holdings in Florida names. In addition, many of these issues have weaker underlying credits, thus reducing their liquidity at current market prices. As these Florida names have underperformed the national market, this has detracted from recent performance. The Trust’s cash allocation (5% at period end) also hampered results as cash equivalents are currently trading at record-low yields and, consequently, detracted from income.

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.

Trust Information

Symbol on NYSE	BAF
Initial Offering Date	October 31, 2002
Yield on Closing Market Price as of February 28, 2010 ($14.00)1	5.87%
Tax Equivalent Yield2	9.03%
Current Monthly Distribution per Common Share3	$0.0685
Current Annualized Distribution per Common Share3	$0.8220
Leverage as of February 28, 20104	36%

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	A change in the distribution rate was declared on March 1, 2010. The Monthly Distribution per Common Share was increased to $0.0735. The Yield on Closing Market Price, Current Monthly Distribution per Common Share and Current Annualized Distribution per Common Share do not reflect the new distribution rate. The new distribution rate is not constant and is subject to change in the future.
4	Represents Preferred Shares and TOBs as a percentage of total managed assets, which is the total assets of the Trust, including any assets attributable to Preferred Shares and TOBs, minus the sum of accrued liabilities. For a discussion of leveraging techniques utilized by the Trust, please see The Benefits and Risks of Leveraging on page 11.

The table below summarizes the changes in the Trust’s market price and NAV per share:

	2/28/10		8/31/09		Change			High		Low
Market Price	$	14.00	$	13.01		7.61	%	$	14.13	$	12.67
Net Asset Value	$	14.31	$	14.06		1.78	%	$	15.10	$	13.99

The following charts show the sector and credit quality allocations of the Trust’s long-term investments:

Sector Allocations

	2/28/10		8/31/09
County/City/Special District/School District	43	%	46	%
Utilities	26		27
Health	12		10
State	10		9
Transportation	8		7
Housing	1		1

Credit Quality Allocations⁵

	2/28/10		8/31/09
AAA/Aaa	53	%	44	%
AA/Aa	28		29
A	14		20
Not Rated6	5		7

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 February 28, 2010 and August 31, 2009, the market value of these securities was $8,649,540 representing 5% and $7,552,594 representing 4%, respectively, of the Trust’s long-term investments.

SEMI-ANNUAL REPORT FEBRUARY 28, 2010 5

Trust Summary as of February 28, 2010 BlackRock Municipal Bond Trust

Investment Objective

BlackRock Municipal Bond Trust (BBK) (the “Trust”) seeks to provide current income exempt from regular federal income taxes. Under normal market conditions, the Trust will invest at least 80% of its managed assets in municipal bonds that are investment grade quality, or determined by the investment advisor to be of equivalent credit quality at time of purchase. The Trust may invest up to 20% of its total assets in municipal bonds that are rated, at the time of investment, Ba/BB or B by Moody’s, S&P or Fitch or that are unrated but judged to be of comparable quality by BlackRock.

          No assurance can be given that the Trust’s investment objective will be achieved.

Performance

For the six months ended February 28, 2010, the Trust returned 8.01% based on market price and 10.31% based on NAV. For the same period, the closed-end Lipper General Municipal Debt Funds (Leveraged) category posted an average return of 9.67% on a market price basis and 8.84% on a NAV basis. All returns reflect reinvestment of dividends. The Trust’s premium to NAV, which narrowed during the period, accounts for the difference between performance based on price and performance based on NAV. Concentrations in lower-rated bonds and a focus on bonds with longer-dated maturities benefited Trust performance over the six months, as credit spreads continued to tighten and municipal rates declined across the yield curve. Within an overall context of being neutral to slightly long duration, we pursued opportunities to add positive convexity to the portfolio by adding discount-coupon bonds and greater call protection. This also proved advantageous as these bonds afforded the portfolio slightly greater capital appreciation as the market rallied. Moreover, in recognition that retail investors have become one of the prime drivers of municipal demand, we actively sought to diversify the portfolio into retail-attractive structures and names via the new-issue market; these purchases incrementally helped total return during the reporting period. On the other hand, the Trust’s positions in zero-coupon bonds hindered performance as these issues have underperformed the broader municipal market. Also negatively affecting performance were the Trust’s existing weighting in higher-coupon, cushion bonds, as well as its lack of exposure to education and essential service credits.

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.

Trust Information

Symbol on NYSE	BBK
Initial Offering Date	April 30, 2002
Yield on Closing Market Price as of February 28, 2010 ($14.37)1	7.10%
Tax Equivalent Yield2	10.92%
Current Monthly Distribution per Common Share3	$0.085
Current Annualized Distribution per Common Share3	$1.020
Leverage as of February 28, 20104	37%

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	Represents Preferred Shares and TOBs as a percentage of total managed assets, which is the total assets of the Trust, including any assets attributable to Preferred Shares and TOBs, minus the sum of accrued liabilities. For a discussion of leveraging techniques utilized by the Trust, please see The Benefits and Risks of Leveraging on page 11.

The table below summarizes the changes in the Trust’s market price and NAV per share:

	2/28/10		8/31/09		Change			High		Low
Market Price	$	14.37	$	13.80		4.13	%	$	15.05	$	13.25
Net Asset Value	$	14.07	$	13.23		6.35	%	$	14.48	$	13.23

The following charts show the sector and credit quality allocations of the Trust’s long-term investments:

Sector Allocations

	2/28/10		8/31/09
Health	23	%	31	%
Housing	17		16
County/City/Special District/School District	13		13
State	12		10
Corporate	9		8
Utilities	8		7
Education	8		5
Transportation	7		7
Tobacco	3		3

Credit Quality Allocations⁵

	2/28/10		8/31/09
AAA/Aaa	27	%	25	%
AA/Aa	22		20
A	23		24
BBB/Baa	19		17
BB/Ba	—		1
B	4		4
Not Rated6	5		9

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 February 28, 2010 and August 31, 2009, the market value of these securities was $3,031,988 representing 1% and $4,472,353 representing 2%, respectively, of the Trust’s long-term investments.

6 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

Trust Summary as of February 28, 2010 BlackRock Municipal Bond Investment Trust

Investment Objective

BlackRock Municipal Bond Investment Trust (BIE) (the “Trust”) seeks to provide current income exempt from regular federal income taxes and Florida intangible personal property tax. Under normal market conditions, the Trust will invest at least 80% of its managed assets in municipal bonds that are investment grade quality, or determined by the investment advisor to be of equivalent credit quality at time of purchase. The Trust may invest up to 20% of its managed assets in municipal bonds that are rated, at the time of purchase, Ba/BB or B by Moody’s, S&P or Fitch or that are unrated but judged to be of comparable quality by BlackRock. The Trust may invest in municipal obligations regardless of geographic location.

     No assurance can be given that the Trust’s investment objective will be achieved.

Performance

For the six months ended February 28, 2010, the Trust returned 6.57% based on market price and 6.50% based on NAV. For the same period, the closed-end Lipper General Municipal Debt Funds (Leveraged) category posted an average return of 9.67% on a market price basis and 8.84% on a NAV basis. All returns reflect reinvestment of dividends. The Trust’s discount to NAV, which narrowed during the period, accounts for the difference between performance based on price and performance based on NAV. The Trust held a higher concentration in health care and housing bonds with maturities of 20 years and longer, which benefited performance as the municipal yield curve flattened during the last six months. Meanwhile, we continued to restructure the Trust’s holdings in line with its transition from a Florida fund to a national portfolio. The process is not yet complete, however, and the higher concentration of Florida holdings detracted from recent performance.

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.

Trust Information

Symbol on NYSE	BIE
Initial Offering Date	April 30, 2002
Yield on Closing Market Price as of February 28, 2010 ($13.62)1	6.50%
Tax Equivalent Yield2	10.00%
Current Monthly Distribution per Common Share3	$0.0738
Current Annualized Distribution per Common Share3	$0.8856
Leverage as of February 28, 20104	38%

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	A change in the distribution rate was declared on March 1, 2010. The Monthly Distribution per Common Share was increased to $0.0788. The Yield on Closing Market Price, Current Monthly Distribution per Common Share and Current Annualized Distribution per Common Share do not reflect the new distribution rate. The new distribution rate is not constant and is subject to change in the future.
4	Represents Preferred Shares and TOBs as a percentage of total managed assets, which is the total assets of the Trust, including any assets attributable to Preferred Shares and TOBs, minus the sum of accrued liabilities. For a discussion of leveraging techniques utilized by the Trust, please see The Benefits and Risks of Leveraging on page 11.

The table below summarizes the changes in the Trust’s market price and NAV per share:

	2/28/10		8/31/09		Change		High		Low
Market Price	$	13.62	$	13.20		3.18%	$	14.40	$	12.65
Net Asset Value	$	14.60	$	14.16		3.11%	$	15.40	$	14.08

The following charts show the sector and credit quality allocations of the Trust’s long-term investments:

Sector Allocations
	2/28/10	8/31/09
Utilities	24%	21%
County/City/Special District/School District	20	20
Health	20	22
Transportation	15	13
Education	8	10
State	7	8
Housing	5	5
Corporate	1	1

Credit Quality Allocations5
	2/28/10	8/31/09
AAA/Aaa	13%	16%
AA/Aa	58	45
A	22	27
BBB/Baa	6	3
BB/Ba	1	1
Not Rated	—	86

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 August 31, 2009, the market value of these securities was $2,503,826 representing 3% of the Trust’s long-term investments.

SEMI-ANNUAL REPORT FEBRUARY 28, 2010 7

Trust Summary as of February 28, 2010 BlackRock Municipal Income Trust II

Investment Objective

BlackRock Municipal Income Trust II (BLE) (the “Trust”) seeks to provide high current income exempt from regular federal income taxes. Under normal market conditions, the Trust will invest at least 80% of its managed assets in municipal bonds that are investment grade quality, or determined by the investment advisor to be of equivalent credit quality at time of purchase. The Trust may invest up to 20% of its total assets in municipal bonds that are rated, at the time of investment, Ba/BB or B by Moody’s, S&P or Fitch or that are unrated but judged to be of comparable quality by BlackRock.

          No assurance can be given that the Trust’s investment objective will be achieved.

Performance

For the six months ended February 28, 2010, the Trust returned 4.36% based on market price and 10.57% based on NAV. For the same period, the closed-end Lipper General Municipal Debt Funds (Leveraged) category posted an average return of 9.67% on a market price basis and 8.84% on a NAV basis. All returns reflect reinvestment of dividends. The Trust moved from a premium to NAV to a discount by period end, which accounts for the difference between performance based on price and performance based on NAV. Contributing factors to Trust performance included the portfolio’s long duration posture throughout much of the period, concentrations in lower-rated bonds and a focus on bonds with longer-dated maturities. Additionally, declining municipal rates across the yield curve, coupled with the ongoing contraction in credit spreads, favored performance. Conversely, the Trust’s positions in long-dated capital appreciation bonds (zeros) hindered performance as these issues underperformed the broader municipal market. We expect this underappreciated corner of the municipal market to regain its luster as the yield curve loses some of its current steepness and investors continue to reach for yield, ultimately helping to drive further gains for the Trust. The Trust’s cash allocation (6% at period end) also hampered results as cash equivalents are currently trading at record-low yields and, consequently, detracted from income.

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.

Trust Information

Symbol on NYSE Amex	BLE
Initial Offering Date	July 30, 2002
Yield on Closing Market Price as of February 28, 2010 ($13.54)1	7.18%
Tax Equivalent Yield2	11.05%
Current Monthly Distribution per Common Share3	$0.081
Current Annualized Distribution per Common Share3	$0.972
Leverage as of February 28, 20104	37%

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	Represents Preferred Shares and TOBs as a percentage of total managed assets, which is the total assets of the Trust, including any assets attributable to Preferred Shares and TOBs, minus the sum of accrued liabilities. For a discussion of leveraging techniques utilized by the Trust, please see The Benefits and Risks of Leveraging on page 11.

The table below summarizes the changes in the Trust’s market price and NAV per share:

	2/28/10		8/31/09		Change		High		Low
Market Price	$	13.54	$	13.45		0.67%	$	14.49	$	12.72
Net Asset Value	$	13.63	$	12.78		6.65%	$	14.05	$	12.78

The following charts show the sector and credit quality allocations of the Trust’s long-term investments:

Sector Allocations
	2/28/10	8/31/09
State	17%	15%
Health	16	20
Utilities	13	12
Corporate	13	11
County/City/Special District	12	8
Transportation	10	12
Education	8	10
Housing	7	8
Tobacco	4	4

Credit Quality Allocations5
	2/28/10	8/31/09
AAA/Aaa	18%	22%
AA/Aa	21	12
A	27	26
BBB/Baa	19	23
BB/Ba	1	1
B	7	6
CCC/Caa	1	1
Not Rated6	6	9

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 February 28, 2010 and August 31, 2009, the market value of these securities was $11,535,337 representing 2% and $16,290,531 representing 4%, respectively, of the Trust’s long-term Investments.

8 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

Trust Summary as of February 28, 2010 BlackRock MuniHoldings Insured Investment Fund

Investment Objective

BlackRock MuniHoldings Insured Investment Fund (MFL) (the “Trust”) seeks to provide shareholders with current income exempt from federal income tax. The Trust also seeks to offer shareholders the opportunity to own shares, the value of which is exempt from Florida intangible personal property tax. Under normal circumstances, the Trust invests at least 80% of its assets in municipal bonds either (i) insured under an insurance policy purchased by the Trust or (ii) insured under an insurance policy obtained by the issuer of the municipal bond or any other party. Such municipal bonds will be insured by insurers or other entities with claims-paying abilities rated at least investment grade at time of purchase. The Trust may invest in municipal obligations regardless of geographic location.

          No assurance can be given that the Trust’s investment objective will be achieved.

Performance

For the six months ended February 28, 2010, the Fund returned 6.84% based on market price and 5.82% based on NAV. For the same period, the closed-end Lipper Insured Municipal Debt Funds (Leveraged) category posted an average return of 8.13% on a market price basis and 6.47% on a NAV basis. All returns reflect reinvestment of dividends. The Trust’s discount to NAV, which narrowed during the period, accounts for the difference between performance based on price and performance based on NAV. The Trust held a higher concentration in health care and housing bonds with maturities of 20 years and longer, which benefited performance as the municipal yield curve flattened during the last six months. On the downside, the lack of availability in the national insured market has made it difficult to fully transition the portfolio away from its holdings in Florida names. In addition, many of these issues have weaker underlying credits, thus reducing their liquidity at current market prices. As these Florida names underperformed the national market, this detracted from recent performance.

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.

Trust Information

Symbol on NYSE	MFL
Initial Offering Date	September 26, 1997
Yield on Closing Market Price as of February 28, 2010 ($13.08)1	6.24%
Tax Equivalent Yield2	9.60%
Current Monthly Distribution per Common Share3	$0.068
Current Annualized Distribution per Common Share3	$0.816
Leverage as of February 28, 20104	38%

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	The equivalent yield assumes the maximum federal tax rate of 35%.
3	A change in the distribution rate was declared on March 1, 2010. The Monthly Distribution per Common Share was increased to $0.073. The Yield on Closing Market Price, Current Monthly Distribution per Common Share and Current Annualized Distribution per Common Share do not reflect the new distribution rate. The new distribution rate is not constant and is subject to change in the future.
4	Represents Preferred Shares and TOBs as a percentage of total managed assets, which is the total assets of the Trust, including any assets attributable to Preferred Shares and TOBs, minus the sum of accrued liabilities. For a discussion of leveraging techniques utilized by the Trust, please see The Benefits and Risks of Leveraging on page 11.

The table below summarizes the changes in the Trust’s market price and NAV per share:

	2/28/10		8/31/09		Change			High		Low
Market Price	$	13.08	$	12.63		3.56	%	$	13.53	$	12.24
Net Asset Value	$	13.92	$	13.57		2.58	%	$	14.43	$	13.57

The following charts show the sector and credit quality allocations of the Trust’s long-term investments:

Sector Allocations
	2/28/10	8/31/09
Utilities	28%	32%
County/City/Special District/School District	24	21
Transportation	21	21
Health	11	10
State	9	6
Housing	5	4
Education	2	6

Credit Quality Allocations5
	2/28/10	8/31/09
AAA/Aaa	57%	56%
AA/Aa	22	16
A	19	25
Not Rated6	2	3

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 February 28, 2010 and August 31, 2009, the market value of these securities was $12,972,106 representing 2% and $20,244,144 representing 3%, respectively, of the Trust’s long-term investments.

SEMI-ANNUAL REPORT FEBRUARY 28, 2010 9

Trust Summary as of February 28, 2010 BlackRock MuniVest Fund, Inc.

Investment Objective

BlackRock MuniVest Fund, Inc. (MVF) (the “Trust”) seeks to provide shareholders with as high a level of current income exempt from federal income taxes as is consistent with its investment policies and prudent investment management by investing primarily in a portfolio of long-term, investment grade municipal obligations, the interest on which is exempt from federal income taxes in the opinion of bond counsel to the issuer.

	No assurance can be given that the Trust’s investment objective will be achieved.
Performance

For the six months ended February 28, 2010, the Trust returned 11.91% based on market price and 8.97% based on NAV. For the same period, the closed-end Lipper General Municipal Debt Funds (Leveraged) category posted an average return of 9.67% on a market price basis and 8.84% on a NAV basis. All returns reflect reinvestment of dividends. The Trust moved from a discount to NAV to a premium by period end, which accounts for the difference between performance based on price and performance based on NAV. The Trust benefited from our effort to increase the portfolio weighting in interest-rate-sensitive bonds as tax-exempt, thirty-year interest rates rallied 25 basis points (0.25%) lower for the six months. A low exposure to zero-coupon bonds also contributed to performance as these issues remained out of favor with investors and underperformed current coupon bonds throughout the period. Conversely, relative performance was negatively affected by the Trust’s below-market exposure to weaker credits as credit spreads generally tightened during the period.

	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.
Trust Information

Symbol on NYSE Amex	MVF
Initial Offering Date	September 29, 1988
Yield on Closing Market Price as of February 28, 2010 ($9.64)1	6.60%
Tax Equivalent Yield2	10.15%
Current Monthly Distribution per Common Share3	$0.053
Current Annualized Distribution per Common Share3	$0.636
Leverage as of February 28, 20104	39%

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	A change in the distribution rate was declared on March 1, 2010. The Monthly Distribution per Common Share was increased to $0.0545. The Yield on Closing Market Price, Current Monthly Distribution per Common Share and Current Annualized Distribution per Common Share do not reflect the new distribution rate. The new distribution rate is not constant and is subject to change in the future.
4	Represents Preferred Shares and TOBs as a percentage of total managed assets, which is the total assets of the Trust, including any assets attributable to Preferred Shares and TOBs, minus the sum of accrued liabilities. For a discussion of leveraging techniques utilized by the Trust, please see The Benefits and Risks of Leveraging on page 11.

The table below summarizes the changes in the Trust’s market price and NAV per share:

		2/28/10		8/31/09	Change			High		Low
Market Price	$	9.64	$	8.91	8.19	%	$	9.89	$	8.76
Net Asset Value	$	9.46	$	8.98	5.35	%	$	9.75	$	8.98

The following charts show the sector and credit quality allocations of the Trust’s long-term investments:

Sector Allocations
	2/28/10	8/31/09
Health	23%	20%
Corporate	15	13
Transportation	13	11
State	12	15
Utilities	12	15
County/City/Special District/School District	8	10
Education	6	6
Housing	6	5
Tobacco	5	5

Credit Quality Allocations5
	2/28/10	8/31/09
AAA/Aaa	21%	26%
AA/Aa	37	28
A	21	28
BBB/Baa	18	15
B	1	1
Not Rated6	2	2

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 February 28, 2010 and August 31, 2009, the market value of these securities was $18,135,710 representing 2% and $16,779,679 representing 2%, respectively, of the Trust’s long-term investments.

10 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

The Benefits and Risks of Leveraging

The Trusts 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, all the Trusts issue Preferred Shares, which pay dividends at prevailing short-term interest rates, and invest 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 each Trust on its longer-term portfolio investments. To the extent that the total assets of each Trust (including the assets obtained from leverage) are invested in higher-yielding portfolio investments, each Trust’s Common Shareholders will benefit from the incremental net income.

To illustrate these concepts, assume a Trust’s Common Shares capitalization 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 positive slope. In this case, the Trust pays dividends on the $50 million of Preferred Shares based on the lower short-term interest rates. At the same time, the securities purchased by the Trust with assets received from the Preferred Shares issuance earn 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 Trust’s long-term investments, and therefore the Common Shareholders are the beneficiaries of the incremental net income.

If short-term interest rates rise, narrowing the differential between short-term and long-term interest rates, the incremental net income pickup on the Common Shares will be reduced or eliminated completely. Furthermore, 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 Trust pays dividends on the higher short-term interest rate whereas the Trust’s total portfolio earns income based on lower long-term interest rates.

Furthermore, the value of the Trust’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 Trust’s Preferred Shares do not fluctuate in relation to interest rates. As a result, changes in interest rates can influence the Trust’s NAV positively or negatively in addition to the impact on Trust performance from leverage from Preferred Shares discussed above.

The Trusts may also 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 Trusts with economic benefits in periods of declining short-term interest rates, but expose the Trusts to risks during periods of rising short-term interest rates similar to those associated with Preferred Shares issued by the Trusts, as described above. Additionally, fluctuations in the market value of municipal bonds deposited into the TOB trust may adversely affect each Trust’s NAVs per share.

The use of leverage may enhance opportunities for increased returns to the Trusts 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 Trusts’ 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 Trusts’ 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 Trusts’ net income will be less than if leverage had not been used, and therefore the amount available for distribution to Common Shareholders will be reduced. Each Trust may be required to sell portfolio securities at inopportune times or at distressed 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 a Trust to incur losses. The use of leverage may limit each Trust’s 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 the Trust. Each Trust will incur expenses in connection with the use of leverage, all of which are borne by the Common Shareholders and may reduce income to the Common Shares.

Under the Investment Company Act of 1940, the Trusts are permitted to issue Preferred Shares in an amount up to 50% of their total managed assets at the time of issuance. Under normal circumstances, each Trust anticipates that the total economic leverage from Preferred Shares and/or TOBs will not exceed 50% of its total managed assets at the time such leverage is incurred. As of February 28, 2010, the Trusts had economic leverage from Preferred Shares and/or TOBs as a percentage of their total managed assets as follows:

	Percent of Leverage
BYM	35%
BAF	36%
BBK	37%
BIE	38%
BLE	37%
MFL	38%
MVF	39%

Derivative Financial Instruments

The Trusts may invest in various derivative instruments, including financial futures contracts, as specified in Note 2 of the Notes to Financial Statements, which constitute forms of economic leverage. Such instruments are used to obtain exposure to a market without owning 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 counterparty to the transaction or illiquidity of the derivative instrument. The Trusts’ ability to successfully use a derivative instrument depends on the investment 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 the Trusts to sell or purchase portfolio securities at inopportune times or for distressed values, may limit the amount of appreciation the Trusts can realize on an investment or may cause the Trusts to hold a security that they might otherwise sell. The Trusts’ investments in these instruments are discussed in detail in the Notes to Financial Statements.

SEMI-ANNUAL REPORT FEBRUARY 28, 2010 11

Schedule of Investments February 28, 2010 (Unaudited)	BlackRock Insured Municipal Income Trust (BYM)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Alabama — 1.3%
Alabama Public School & College Authority, Refunding RB, Series A, 5.00%, 5/01/29	$	1,000	$	1,046,390
Birmingham Special Care Facilities Financing Authority, RB, Children’s Hospital (AGC), 6.00%, 6/01/39		1,495		1,611,072
County of Jefferson Alabama, RB, Series A, 4.75%, 1/01/25		2,800		2,181,396
				4,838,858
Arizona — 0.6%
State of Arizona, COP, Department of Administration, Series A (AGM):
5.00%, 10/01/27		1,500		1,541,370
5.25%, 10/01/28		650		675,805
				2,217,175
California — 29.7%
Arcadia Unified School District California, GO, CAB, Election of 2006, Series A (AGM), 4.96%, 8/01/39 (a)		2,000		283,000
California Health Facilities Financing Authority, Refunding RB, St. Joseph Health System, Series A, 5.75%, 7/01/39		625		645,006
California Infrastructure & Economic Development Bank, RB, Bay Area Toll Bridges, First Lien, Series A (AMBAC), 5.00%, 7/01/28 (b)		10,100		11,789,124
California State Department of Water Resources, RB, Series A, 5.38%, 5/01/12 (b)		2,500		2,779,225
Coast Community College District California, GO, Refunding, CAB, Election of 2002, Series C (AGM):
5.58%, 8/01/13 (c)		7,450		6,327,955
5.40%, 8/01/36 (a)		4,200		752,976
Fresno Unified School District California, GO, Election of 2001, Series E (AGM), 5.00%, 8/01/30		1,100		1,121,153
Golden State Tobacco Securitization Corp., California, RB, Series 2003-A-1 (b):
6.63%, 6/01/13		6,500		7,629,765
6.75%, 6/01/13		14,500		17,037,355
Los Angeles Municipal Improvement Corp., RB, Series B1 (NPFGC), 4.75%, 8/01/37		4,000		3,567,160
Metropolitan Water District of Southern California, RB, Series B-1 (NPFGC), 5.00%, 10/01/33		17,500		17,821,825
Monterey Peninsula Community College District, GO, CAB, Series C (AGM) (a):
5.15%, 8/01/31		13,575		3,560,180
5.16%, 8/01/32		14,150		3,464,345
Orange County Sanitation District, COP, Series B (AGM), 5.00%, 2/01/31		2,500		2,609,950

Municipal Bonds	Par (000)		Value
California (concluded)
Sacramento Unified School District California, GO, Election of 2002 (NPFGC), 5.00%, 7/01/30	$	2,700	$	2,717,442
San Francisco City & County Public Utilities Commission, Refunding RB, Series A (AGM), 5.00%, 11/01/31		15,000		15,109,500
San Joaquin Hills Transportation Corridor Agency California, Refunding RB, CAB, Series A (NPFGC), 5.49%, 1/15/31 (a)		53,000		9,315,280
San Jose Unified School District Santa Clara County California, GO, Election of 2002, Series B (NPFGC), 5.00%, 8/01/29		2,350		2,415,095
				108,946,336
District of Columbia — 2.6%
District of Columbia Tobacco Settlement Financing Corp., Refunding RB, Asset-Backed, 6.75%, 5/15/40		9,500		9,518,050
Florida — 13.3%
Broward County School Board Florida, COP, Series A (AGM), 5.25%, 7/01/33		2,000		2,052,860
City of Tallahassee Florida, RB (NPFGC), 5.00%, 10/01/32		3,000		3,045,330
County of Broward Florida, RB, Series A, 5.25%, 10/01/34		950		983,839
County of Duval Florida, COP, Master Lease Program (AGM), 5.00%, 7/01/33		2,800		2,773,176
County of Miami-Dade Florida, RB:
CAB, Sub-Series A (NPFGC), 5.25%, 10/01/38 (a)		25,520		3,528,395
Jackson Health System (AGC), 5.75%, 6/01/39		2,300		2,401,476
County of Miami Dade, Florida, RB, Miami Dade County Water & Sewer System (AGM), 5.00%, 10/01/39 (d)		10,100		10,068,589
County of Miami-Dade Florida, Refunding RB (AGM), 5.00%, 7/01/35		1,300		1,314,950
Florida Housing Finance Corp., RB, Homeowner Mortgage, Series 3 (GNMA), 5.45%, 7/01/33		4,715		4,849,472
Florida State Department of Environmental Protection, RB, Series B (NPFGC), 5.00%, 7/01/27		7,500		7,816,425
Miami-Dade County School Board, COP, Refunding, Series B (AGC), 5.25%, 5/01/31		3,600		3,713,184
Orange County School Board, COP, Series A (AGC), 5.50%, 8/01/34		5,590		5,909,860
Sarasota County Public Hospital District, RB, Sarasota Memorial Hospital Project, Series A, 5.63%, 7/01/39		300		305,763
				48,763,319

Portfolio Abbreviations
To simplify the listings of portfolio holdings in the Schedules of Investments, the names and descriptions of many of the securities have been abbreviated according to the following list:
ACA	American Capital Access Corp.
AGC	Assured Guaranty Corp.
AGM	Assured Guaranty Municipal Corp.
AMBAC	American Municipal Bond Assurance Corp.
AMT	Alternative Minimum Tax (subject to)
ARB	Airport Revenue Bonds
ARS	Auction Rate Securities
BHAC	Berkshire Hathaway Assurance Corp.
CAB	Capital Appreciation Bonds
CIFG	CDC IXIS Financial Guaranty
COP	Certificates of Participation
EDA	Economic Development Authority
EDC	Economic Development Corp.
ERB	Education Revenue Bonds
FHA	Federal Housing Administration
FGIC	Financial Guaranty Insurance Co.
GAN	Grant Anticipation Notes
GARB	General Airport Revenue Bonds
GNMA	Government National Mortgage Association
GO	General Obligation Bonds
HDA	Housing Development Authority
HFA	Housing Finance Agency
HRB	Housing Revenue Bonds
IDA	Industrial Development Authority
IDB	Industrial Development Board
IDRB	Industrial Development Revenue Bond
ISD	Independent School District
M/F	Multi-Family
MRB	Mortgage Revenue Bonds
NPFGC	National Public Finance Guarantee Corp.
PILOT	Payment in Lieu of Taxes
PSF-GTD	Permanent School Fund Guaranteed
RAN	Revenue Anticipation Notes
RB	Revenue Bonds
S/F	Single Family
VRDN	Variable Rate Demand Notes

See Notes to Financial Statements.
12	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (continued)	BlackRock Insured Municipal Income Trust (BYM)
	(Percentages shown are based on Net Assets)

	Par (000)		Value
Municipal Bonds
Georgia — 0.3%
Gwinnett County Hospital Authority, Refunding RB, Gwinnett Hospital System, Series D (AGM), 5.50%, 7/01/41	$	900	$	907,785
Illinois — 4.9%
Chicago Board of Education Illinois, GO, Refunding, Chicago School Reform Board, Series A (NPFGC), 5.50%, 12/01/26		2,500		2,807,650
City of Chicago Illinois, GO, Refunding, Series A (AGM), 5.00%, 1/01/25		1,000		1,056,970
City of Chicago Illinois, RB, Series A (AGC), 5.00%, 1/01/38		7,310		7,447,282
Illinois Municipal Electric Agency, RB, Series A (NPFGC), 5.25%, 2/01/27		4,800		5,035,440
State of Illinois, RB, Build Illinois, Series B, 5.25%, 6/15/34		1,400		1,440,376
				17,787,718
Indiana — 0.7%
Indiana Municipal Power Agency, RB:
Indiana Municipal Power Agency, Series B, 5.75%, 1/01/34		450		462,757
Series A (NPFGC), 5.00%, 1/01/37		2,050		2,017,118
				2,479,875
Iowa — 1.4%
Iowa Finance Authority, RB, Series A (AGC), 5.63%, 8/15/37		5,000		5,195,100
Kentucky — 0.4%
Kentucky State Property & Buildings Commission, Refunding RB, Project No. 93 (AGC), 5.25%, 2/01/29		1,500		1,609,305
Louisiana — 2.1%
State of Louisiana, RB, Series A (AGM), 5.00%, 5/01/31		7,500		7,728,450
Michigan — 4.9%
City of Detroit Michigan, RB:
Senior Lien, Series A (NPFGC), 5.00%, 7/01/30		1,000		972,560
Senior Lien, Series A (NPFGC), 5.00%, 7/01/34		2,810		2,698,977
System, Second Lien, Series A (BHAC), 5.50%, 7/01/36		2,900		3,005,763
System, Second Lien, Series B (NPFGC), 5.00%, 7/01/33		4,000		3,871,280
System, Second Lien, Series B (NPFGC), 5.00%, 7/01/36		4,400		4,201,384
City of Detroit Michigan, Refunding RB, Second Lien, Series E (BHAC), 5.75%, 7/01/31		3,000		3,208,800
				17,958,764
Nevada — 8.6%
City of Reno Nevada, Refunding RB, Senior Lien, ReTrac-Reno, Transportation Project (AMBAC), 5.13%, 6/01/32 (b)		5,000		5,483,300
County of Clark Nevada, RB:
Las Vegas-McCarran International Airport, Series A (AGC), 5.25%, 7/01/39		4,100		4,112,218
Subordinate Lien, Series A2 (BHAC), 5.00%, 7/01/30		2,500		2,548,700
System, Subordinate Lien, Series C (AGM), 5.00%, 7/01/26		1,650		1,708,459
Truckee Meadows Water Authority, RB, Series A (AGM) (b):
5.00%, 7/01/25		10,000		10,617,400
5.13%, 7/01/30		6,500		6,912,230
				31,382,307

	Par (000)		Value
Municipal Bonds
New York — 0.4%
New York State Dormitory Authority, ERB, Series B, 5.75%, 3/15/36	$	1,300	$	1,451,450
Pennsylvania — 1.5%
City of Philadelphia Pennsylvania, RB, Third Series (AGM), 5.13%, 8/01/11 (b)		5,200		5,544,916
Puerto Rico — 1.7%
Puerto Rico Electric Power Authority, Refunding RB, Series VV (NPFGC), 5.25%, 7/01/30		625		634,362
Puerto Rico Sales Tax Financing Corp., RB, First Sub-Series A, 6.38%, 8/01/39		5,300		5,677,731
				6,312,093
Rhode Island — 0.8%
Rhode Island Health & Educational Building Corp., Refunding RB, Public Schools Financing Program, Series E (AGC), 6.00%, 5/15/29		2,625		2,896,320
South Carolina — 2.9%
South Carolina Transportation Infrastructure Bank, RB, Junior Lien, Series B (AMBAC), 5.13%, 10/01/26 (b)		10,000		10,733,100
Tennessee — 5.6%
Knox County Health Educational & Housing Facilities Board Tennessee, Refunding RB (AGM), Series A (a):
CAB, 5.84%, 1/01/22		11,705		6,104,977
CAB, 5.88%, 1/01/23		9,260		4,516,750
CAB, 5.90%, 1/01/24		8,500		3,893,340
CAB, 5.91%, 1/01/25		6,850		2,950,363
CAB, 5.93%, 1/01/26		5,000		2,021,000
Covenant, 4.71%, 1/01/41		8,250		1,195,178
				20,681,608
Texas — 30.0%
City of Houston Texas, RB, Senior Lien, Series A, 5.50%, 7/01/34		4,165		4,457,883
City of San Antonio Texas, Refunding RB (NPFGC):
5.13%, 5/15/29		9,250		9,623,885
5.13%, 5/15/34		10,000		10,237,100
Coppell ISD Texas, GO, Refunding, CAB (PSF-GTD), 5.64%, 8/15/30 (a)		10,030		3,883,115
County of Harris Texas, GO (NPFGC) (a):
5.56%, 8/15/25		7,485		3,970,942
5.59%, 8/15/28		10,915		4,876,822
County of Harris Texas, Refunding RB, Senior Lien, Toll Road (AGM), 5.00%, 8/15/30		5,510		5,711,005
Harris County-Houston Sports Authority, Texas, Refunding RB (NPFGC) (a):
CAB, Junior Lien, Series H, 5.92%, 11/15/38		5,785		727,811
CAB, Junior Lien, Series H, 5.93%, 11/15/39		6,160		720,966
Third Lien, Series A-3, 5.97%, 11/15/38		26,890		3,383,031
Third Lien, Series A-3, 5.98%, 11/15/39		27,675		3,235,484
Lewisville ISD Texas, GO, Refunding, CAB, School Building (NPFGC), 4.67%, 8/15/24 (a)		5,315		2,701,880
Mansfield ISD Texas, GO, School Building (PSF-GTD), 5.00%, 2/15/33		2,980		3,137,433
North Texas Tollway Authority, Refunding RB:
CAB, System, First Tier (AGC), 5.32%, 1/01/29 (a)		5,000		1,708,300
CAB, System, First Tier (AGC), 5.44%, 1/01/30 (a)		1,750		558,303
First Tier, Series A, 6.00%, 1/01/28		625		674,294
System, First Tier (NPFGC), 5.75%, 1/01/40		23,050		23,736,890
Texas State Turnpike Authority, RB, First Tier, Series A (AMBAC), 5.00%, 8/15/42		28,145		26,634,739
				109,979,883

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	13

Schedule of Investments (continued)	BlackRock Insured Municipal Income Trust (BYM)
	(Percentages shown are based on Net Assets)

	Par (000)		Value
Municipal Bonds
Washington — 6.7%
Chelan County Public Utility District No. 1, RB, Chelan Hydro System, Series C (AMBAC), 5.13%, 7/01/33	$	3,655	$	3,697,837
County of King Washington, Refunding RB (AGM), 5.00%, 1/01/36		2,200		2,255,880
Port of Seattle Washington, RB, Series A (NPFGC), 5.00%, 4/01/31		4,500		4,529,970
State of Washington, GO, Various Purpose, Series 02-A (AGM), 5.00%, 7/01/25		6,380		6,488,141
Washington Health Care Facilities Authority, RB, MultiCare Health Care, Series C (AGC), 5.50%, 8/15/43		6,600		6,706,986
Washington Health Care Facilities Authority, Refunding RB, MultiCare Health System, Series A (AGM), 5.50%, 8/15/38		700		716,632
				24,395,446
Total Municipal Bonds — 120.4%				441,327,858

Municipal Bonds Transferred to Tender Option Bond Trusts (e)
Arizona — 0.4%
Phoenix Civic Improvement Corp, RB, Junior Lien, Series A, 5.00%, 7/01/34	1,300	1,352,091
California — 5.6%
Los Angeles Community College District, California, GO, Election of 2001, Series A (AGM), 5.00%, 8/01/32	5,000	5,043,050
San Diego Community College District California, GO, Election of 2002, 5.25%, 8/01/33	449	462,497
San Diego County Water Authority, COP, Refunding, Series 2008-A (AGM), 5.00%, 5/01/33	4,870	4,954,689
University of California, RB, Series C (NPFGC), 4.75%, 5/15/37	10,000	10,022,100
		20,482,336
District of Columbia — 0.3%
District of Columbia, RB, Series A, 5.50%, 12/01/30	1,080	1,210,745
Florida — 2.2%
City of Tallahassee Florida, RB (NPFGC), 5.00%, 10/01/37	5,000	5,024,850
Florida State Board of Education, GO, Series D, 5.00%, 6/01/37	2,999	3,084,345
		8,109,195
Illinois — 8.0%
Illinois State Toll Highway Authority, RB, Series B, 5.50%, 1/01/33	4,499	4,818,269
Metropolitan Pier & Exposition Authority, Illinois, RB, McCormick Place Expansion, Series A (NPFGC), 5.00%, 12/15/28	24,010	24,520,933
		29,339,202
Massachusetts — 3.7%
Massachusetts School Building Authority, RB, Series A (AGM), 5.00%, 8/15/30	12,987	13,522,568
Nevada — 1.8%
City of Las Vegas, Nevada, GO, Limited Tax, Performing Arts Center, 6.00%, 4/01/39	4,197	4,571,641
Clark County Water Reclamation District, GO, Series B, 5.75%, 7/01/34	2,024	2,228,551
		6,800,192

Municipal Bonds Transferred to Tender Option Bond Trusts (e)	Par (000)		Value
New York — 4.6%
Erie County Industrial Development Agency, RB, City School District of Buffalo Project, Series A (AGM), 5.75%, 5/01/28	$	4,494	$	4,908,021
Metropolitan Transportation Authority, RB, Series A (NPFGC), 5.00%, 11/15/31		7,002		7,227,073
Triborough Bridge & Tunnel Authority, RB, General, Series A-2, 5.25%, 11/15/34		4,500		4,784,265
				16,919,359
Ohio — 0.2%
State of Ohio, RB, Cleveland Clinic Health, Series B, 5.50%, 1/01/34		620		650,944
South Carolina — 0.2%
South Carolina State Public Service Authority, RB, Santee Cooper, Series A, 5.50%, 1/01/38		600		647,898
Texas — 2.8%
Northside ISD, Texas, GO, School Building (PSF-GTD), 5.13%, 6/15/29		9,500		10,100,079
Utah — 1.4%
Utah Transit Authority, RB, Series A (AGM), 5.00%, 6/15/36		5,000		5,231,250
Virginia — 0.1%
Fairfax County IDA Virginia, Refunding RB, Health Care, Inova Health System, Series A, 5.50%, 5/15/35		400		417,621
Washington — 1.0%
Central Puget Sound Regional Transportation Authority, Washington, RB, Series A (AGM), 5.00%, 11/01/32		3,494		3,650,348
Total Municipal Bonds Transferred to Tender Option Bond Trusts — 32.3%				118,433,828
Total Long-Term Investments (Cost — $556,910,090) — 152.7%				559,761,686

Short-Term Securities
New York — 0.5%
City of New York New York, GO, VRDN, Sub-Series A-6 (AGM), 0.14%, 3/01/10 (f)	1,700	1,700,000

	Shares
Money Market Fund — 1.8%
FFI Institutional Tax-Exempt Fund, 0.16% (g)(h)		6,590,771		6,590,771
Total Short-Term Securities (Cost — $8,290,771) — 2.3%				8,290,771
Total Investments (Cost — $565,200,861*) — 155.0%				568,052,457
Liabilities in Excess of Other Assets — (0.2)%				(761,996	)
Liability for Trust Certificates, Including Interest Expense and Fees Payable — (17.3)%				(63,513,572	)
Preferred Shares, at Redemption Value — (37.5)%				(137,257,176	)
Net Assets Applicable to Common Shares — 100.0%			$	366,519,713

* The cost and unrealized appreciation (depreciation) of investments as of February 28, 2010, as computed for federal income tax purposes, were as follows:

Aggregate cost	$	502,327,457
Gross unrealized appreciation	$	22,859,100
Gross unrealized depreciation		(20,610,097	)
Net unrealized appreciation
	$	2,249,003

See Notes to Financial Statements.
14	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (concluded) BlackRock Insured Municipal Income Trust (BYM)

(a)	Represents a zero-coupon bond. Rate shown reflects the current yield as of report date.
(b)	US 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)	Represents a step-up bond that pays an initial coupon rate for the first period and then a higher coupon rate for the following periods. Rate shown reflects the current yield as of report date.
(d)	When-issued security. Unsettled when-issued security transactions were as follows:

Counterparty	Value		Unrealized Depreciation
Barclays Capital	$	299,067	$	(424	)
Raymond C. Forbes & Co., Inc.	$	9,769,522	$	(13,856	)

(e)	Securities represent bonds transferred to a tender option bond trust in exchange for which the Trust 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.
(f)	Variable rate security. Rate shown is as of report date and maturity shown is the date the principal owed can be recovered through demand.
(g)	Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:

	Net Activity		Income
Affiliate
FFI Institutional Tax-Exempt Fund	$	2,189,027	$	2,101

(h)	Represents the current yield as of report date.
•	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 assets and liabilities
	•	Level 2 — other observable inputs (including, but not limited to: quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)
	•	Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Trust’s own assumptions used in determining the fair value of investments)
	The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in those securities. For information about the Trust’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 February 28, 2010 in determining the fair valuation of the Trust’s investments:

	Investments in Securities
Valuation Inputs	Level 1		Level 2		Level 3		Total
Assets:
Long-Term Investments1		—	$	559,761,686		—	$	559,761,686
Short-Term Securities	$	6,590,771		1,700,000		—		8,290,771
Total	$	6,590,771	$	561,461,686		—	$	568,052,457

¹ See above Schedule of Investments for values in each state or political subdivision.

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	15

Schedule of Investments February 28, 2010 (Unaudited)	BlackRock Insured Municipal Income Investment Trust (BAF)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Alabama — 1.7%
Birmingham Special Care Facilities Financing Authority, RB, Children’s Hospital (AGC):
6.13%, 6/01/34	$	1,000	$	1,079,430
6.00%, 6/01/39		1,000		1,077,640
				2,157,070
Arizona — 0.5%
State of Arizona, COP, Department of Administration, Series A (AGM):
5.25%, 10/01/28		465		483,460
5.00%, 10/01/29		125		126,803
				610,263
California — 7.7%
California State Public Works Board, RB, Various Capital Projects, Series G-1 (AGC), 5.25%, 10/01/24		2,000		2,010,380
County of Sacramento California, RB, Senior, Series A (AGC), 5.50%, 7/01/41		1,400		1,460,788
Los Angeles Community College District California, GO, Election of 2001, Series A (NPFGC), 5.00%, 8/01/32		1,000		1,007,370
Los Angeles Municipal Improvement Corp., Refunding RB, Real Property, Series B (AGC), 5.50%, 4/01/39		3,810		3,967,467
San Diego Public Facilities Financing Authority, Refunding RB, Series B (AGC), 5.38%, 8/01/34		1,125		1,178,775
				9,624,780
Colorado — 1.3%
Colorado Health Facilities Authority, RB, Hospital, NCMC Inc. Project, Series B (AGM), 6.00%, 5/15/26		1,425		1,584,743
Florida — 30.4%
City of Jacksonville Florida, RB, Series B (AMBAC), 5.00%, 10/01/26		2,500		2,561,625
City of Miami Florida, RB (NPFGC), 5.25%, 1/01/28		5,035		5,275,270
City of Palm Bay Florida, RB, Improvement (NPFGC), 5.51%, 10/01/28 (a)		1,845		656,193
City of Sunrise Florida, Refunding RB (AMBAC), 5.00%, 10/01/28		5,000		5,147,650
County of Orange Florida, Refunding RB:
(AMBAC), 5.00%, 10/01/29		1,600		1,636,736
Series B (NPFGC), 5.13%, 1/01/32		5,630		5,668,847
Hillsborough County Aviation Authority Florida, Refunding RB, Series D (AGC), 5.50%, 10/01/26		1,295		1,421,263
Lake County School Board, COP, Series A (AMBAC), 5.00%, 7/01/28		3,500		3,501,890
Pasco County School Board, COP, Series A (NPFGC), 5.00%, 8/01/27		2,765		2,833,848
Tohopekaliga Water Authority, RB, Series B (AGM), 5.00%, 10/01/23		1,000		1,045,360
Village Center Community Development District, RB, Series A (NPFGC), 5.00%, 11/01/32		10,000		8,211,800
				37,960,482
Georgia — 2.7%
Gwinnett County Hospital Authority, Refunding RB, Gwinnett Hospital System, Series D (AGM), 5.50%, 7/01/41		1,350		1,361,678
Metropolitan Atlanta Rapid Transit Authority, RB, Third Indenture, Series B (AGM), 5.00%, 7/01/34		1,890		1,960,421
				3,322,099

Municipal Bonds	Par (000)		Value
Illinois — 8.1%
Chicago Board of Education Illinois, GO, Refunding, Chicago School Reform Board, Series A (NPFGC), 5.50%, 12/01/26	$	900	$	1,010,754
Chicago Transit Authority, RB, Federal Transit Administration Section 5309, Series A (AGC), 6.00%, 6/01/26		1,300		1,488,461
City of Chicago Illinois, GO, Refunding, Projects, Series A (AGM):
5.00%, 1/01/28		920		969,698
5.00%, 1/01/29		1,425		1,488,014
5.00%, 1/01/30		570		590,600
City of Chicago Illinois, Refunding RB, Second Lien (NPFGC), 5.50%, 1/01/30		975		1,074,889
Illinois Municipal Electric Agency, RB, Series A (NPFGC), 5.25%, 2/01/28		1,560		1,628,000
State of Illinois, RB, Build Illinois, Series B, 5.25%, 6/15/28		1,750		1,847,387
				10,097,803
Indiana — 1.2%
Indianapolis Local Public Improvement Bond Bank, Refunding RB, Waterworks Project, Series A (AGC), 5.50%, 1/01/38		1,415		1,523,672
Iowa — 0.9%
Iowa Finance Authority, Refunding RB, Iowa Health System (AGC), 5.25%, 2/15/29		1,125		1,156,568
Kentucky — 0.8%
Kentucky Municipal Power Agency, RB, Prairie State Project, Series A (BHAC), 5.25%, 9/01/42		1,000		1,033,830
Louisiana — 2.7%
Louisiana State Citizens Property Insurance Corp., RB, Series C-3 (AGC), 6.13%, 6/01/25		2,510		2,836,576
New Orleans Aviation Board Louisiana, Refunding RB (AGC), Restructuring GARB:
Series A-1, 6.00%, 1/01/23		375		427,999
Series A-2, 6.00%, 1/01/23		150		171,199
				3,435,774
Michigan — 15.8%
City of Detroit Michigan, RB:
Second Lien, Series B (AGM), 6.25%, 7/01/36		1,700		1,847,730
Second Lien, Series B (AGM), 7.00%, 7/01/36		200		229,238
Second Lien, Series B (NPFGC), 5.50%, 7/01/29		1,790		1,799,684
Senior Lien, Series B (AGM), 7.50%, 7/01/33		1,000		1,198,850
Senior Lien, Series B (BHAC), 5.50%, 7/01/35		4,750		4,910,122
System, Second Lien, Series A (BHAC), 5.50%, 7/01/36		2,330		2,414,975
City of Detroit Michigan, Refunding RB:
Second Lien, Series E (BHAC), 5.75%, 7/01/31		2,300		2,460,080
Senior Lien, Series C-1 (AGM), 7.00%, 7/01/27		1,800		2,104,920
Michigan State Building Authority, RB, Facilities Program, Series H (AGM), 5.00%, 10/15/26		365		373,957
Michigan State Building Authority, Refunding RB, Facilities Program, Series I (AGC):
5.25%, 10/15/24		565		608,059
5.25%, 10/15/25		300		320,370
Royal Oak Hospital Finance Authority Michigan, Refunding RB, William Beaumont Hospital, 8.25%, 9/01/39		1,205		1,417,996
				19,685,981

See Notes to Financial Statements.
16	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (continued)	BlackRock Insured Municipal Income Investment Trust (BAF)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Minnesota — 5.1%
City of Minneapolis Minnesota, Refunding RB, Fairview Health Services, Series B (AGC), 6.50%, 11/15/38	$	5,680	$	6,330,871
Nevada — 1.8%
County of Clark Nevada, RB, Las Vegas-McCarran International Airport, Series A (AGC), 5.25%, 7/01/39		2,295		2,301,839
New Jersey — 5.0%
New Jersey EDA, RB, School Facilities Construction, Series Z (AGC), 6.00%, 12/15/34		1,000		1,126,780
New Jersey Health Care Facilities Financing Authority, RB, Virtua Health (AGC), 5.50%, 7/01/38		1,300		1,362,816
New Jersey State Housing & Mortgage Finance Agency, RB, S/F Housing, Series CC, 5.25%, 10/01/29		1,575		1,623,163
New Jersey Transportation Trust Fund Authority, RB, Transportation System, Series A (AGC), 5.50%, 12/15/38		2,000		2,159,000
				6,271,759
New York — 2.9%
New York City Transitional Finance Authority, RB, Fiscal 2009:
Series S-3, 5.25%, 1/15/39		900		942,228
Series S-4 (AGC), 5.50%, 1/15/29		2,465		2,725,526
				3,667,754
Oregon — 0.4%
Medford Hospital Facilities Authority, RB, Asante Health System, Series A (AGC), 5.00%, 8/15/40		490		485,296
Puerto Rico — 1.2%
Puerto Rico Sales Tax Financing Corp., RB, First Sub-Series A, 6.38%, 8/01/39		1,350		1,446,215
Texas — 15.4%
City of Dallas Texas, Refunding RB (AGC), 5.25%, 8/15/38		800		816,744
City of Houston Texas, Refunding RB, Combined, First Lien, Series A (AGC):
6.00%, 11/15/35		2,600		2,948,140
6.00%, 11/15/36		2,215		2,506,162
5.38%, 11/15/38		1,000		1,063,040
Frisco ISD Texas, GO, School Building (AGC):
5.38%, 8/15/39		1,415		1,510,710
5.50%, 8/15/41		3,365		3,624,778
Harris County Health Facilities Development Corp., Refunding RB, Memorial Hermann Healthcare System, Series B, 7.13%, 12/01/31		500		561,390
Lower Colorado River Authority, Refunding RB, LCRA Transmission Services Project (AGC), 5.50%, 5/15/36		1,270		1,327,798
Lubbock Cooper ISD Texas, GO, School Building (AGC), 5.75%, 2/15/42		500		533,155
North Texas Tollway Authority, RB, System, First Tier, Series K-1 (AGC), 5.75%, 1/01/38		1,500		1,622,985
North Texas Tollway Authority, Refunding RB, System, First Tier, Series A (AGC), 5.75%, 1/01/40		1,500		1,607,355
Tarrant County Cultural Education Facilities Finance Corp., Refunding RB, Christus Health, Series A (AGC), 6.50%, 7/01/37		1,000		1,102,350
				19,224,607

Municipal Bonds	Par (000)		Value
Utah — 1.3%
City of Riverton Utah, RB, IHC Health Services Inc., 5.00%, 8/15/41	$	1,625	$	1,632,280
Virginia — 0.9%
Virginia Public School Authority, RB, School Financing, 6.50%, 12/01/35		1,000		1,148,910
Washington — 2.2%
Washington Health Care Facilities Authority, Refunding RB, Providence Health, Series C (AGM), 5.25%, 10/01/33		2,650		2,720,225
Total Municipal Bonds — 110.0%				137,422,821
Municipal Bonds Transferred to Tender Option Bond Trusts (b)
District of Columbia — 0.7%
District of Columbia Water & Sewer Authority, RB, Series A, 6.00%, 10/01/35		760		850,967
Florida — 33.4%
City of Jacksonville Florida, RB (NPFGC):
5.00%, 10/01/31		9,500		9,563,335
Better Jacksonville, 5.00%, 10/01/27		3,930		4,029,822
County of Pinellas Florida, RB (AGM), 5.00%, 10/01/32		9,500		9,564,857
Florida State Board of Education, GO, Public Education, Series A (AGM), 5.00%, 6/01/27		9,000		9,277,830
Palm Beach County School District, COP, Series D (AGM), 5.00%, 8/01/28		9,190		9,285,944
				41,721,788
Illinois — 2.5%
Illinois State Toll Highway Authority, RB, Series B, 5.50%, 1/01/33		3,000		3,212,180
Kentucky — 0.8%
Kentucky State Property & Buildings Commission, Refunding RB, Project No. 93 (AGC), 5.25%, 2/01/27		898		972,374
Nevada — 1.8%
Clark County Water Reclamation District, GO, Limited Tax, 6.00%, 7/01/38		2,000		2,222,880
Total Municipal Bonds Transferred to Tender Option Bond Trusts — 39.2%				48,980,189
Total Long-Term Investments (Cost — $181,363,142) — 149.2%				186,403,010
Short-Term Securities		Shares
FFI Institutional Tax-Exempt Fund, 0.16% (c)(d)		6,303,277		6,303,277
Total Short-Term Securities (Cost — $6,303,277) — 5.0%				6,303,277
Total Investments (Cost — $187,666,419*) — 154.2%				192,706,287
Other Assets Less Liabilities — 2.6%				3,267,326
Liability for Trust Certificates, Including Interest Expense and Fees Payable — (23.0)%				(28,720,147	)
Preferred Shares, at Redemption Value — (33.8)%				(42,277,543	)
Net Assets Applicable to Common Shares — 100.0%			$	124,975,923

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	17

Schedule of Investments (concluded) BlackRock Insured Municipal Income Investment Trust (BAF)

* The cost and unrealized appreciation (depreciation) of investments as of February 28, 2010, as computed for federal income tax purposes, were as follows:

Aggregate cost	$	159,278,853
Gross unrealized appreciation	$	6,941,439
Gross unrealized depreciation		(2,211,361	)
Net unrealized appreciation	$	4,730,078

(a)	Represents a zero-coupon bond. Rate shown reflects the current yield as of report date.
(b)	Securities represent bonds transferred to a tender option bond trust in exchange for which the Trust 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.
(c)	Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:

Affiliate	Net Activity			Income
CMA Florida Municipal Money Fund	$	(5	)		—
FFI Institutional Tax-Exempt Fund	$	(2,899,474	)	$	5,623

(d)	Represents the current yield as of report date.
•	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 assets and liabilities
	•	Level 2 — other observable inputs (including, but not limited to: quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)
	•	Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Trust’s own assumptions used in determining the fair value of investments)
	The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in those securities. For information about the Trust’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 February 28, 2010 in determining the fair valuation of the Trust’s investments:

Valuation Inputs	Level 1		Level 2		Level 3		Total
Assets:
Long-Term Investments1		—	$	186,403,010		—	$	186,403,010
Short-Term Securities	$	6,303,277		—		—		6,303,277
Total	$	6,303,277	$	186,403,010		—	$	192,706,287

¹ See above Schedule of Investments for values in each state or political subdivision.

See Notes to Financial Statements.
18	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments February 28, 2010 (Unaudited)	BlackRock Municipal Bond Trust (BBK)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Alabama — 2.7%
Birmingham Special Care Facilities Financing Authority, RB, Children’s Hospital (AGC):
6.00%, 6/01/34	$	1,150	$	1,240,528
6.00%, 6/01/39		450		484,938
Coosa Valley Water Supply District Inc., RB (AGC):
4.50%, 10/01/34		600		594,684
4.50%, 10/01/36		1,300		1,280,123
4.50%, 10/01/39		400		389,764
				3,990,037
Arizona — 6.6%
City of Goodyear Arizona, GO (AGM), 4.25%, 7/01/37		1,135		1,053,473
Glendale Municipal Property Corp. Arizona, Refunding RB, Series A (AGM), 4.50%, 7/01/32		2,000		2,004,040
Mohave County Unified School District No. 20 Kingman, GO, School Improvement Project of 2006, Series C (AGC), 5.00%, 7/01/26		200		214,492
Pima County IDA, Refunding IDRB, Tucson Electric Power, 5.75%, 9/01/29		900		908,298
Salt Verde Financial Corp., RB, Senior:
5.00%, 12/01/32		1,500		1,311,585
5.00%, 12/01/37		2,065		1,757,769
San Luis Facility Development Corp., RB, Senior Lien, Regional Detention Center Project:
6.25%, 5/01/15		300		279,966
7.00%, 5/01/20		300		278,538
7.25%, 5/01/27		600		550,284
State of Arizona, COP, Department of Administration, Series A (AGM), 5.00%, 10/01/29		750		760,815
University Medical Center Corp., Arizona, RB, 6.50%, 7/01/39		500		530,115
				9,649,375
California — 14.8%
California County Tobacco Securitization Agency, RB, CAB, Stanislaus, Sub-Series C, 6.30%, 6/01/55 (a)		4,500		56,250
California HFA, RB, Home Mortgage, Series G, AMT, 5.05%, 2/01/29		2,835		2,607,746
California State Department of Veterans Affairs, RB, Series B, AMT, 5.25%, 12/01/37		5,000		4,477,050
Carlsbad Unified School District, GO, Election, Series B, 6.09%, 5/01/34 (b)		1,000		621,620
Dinuba Unified School District, GO, Election 2006 (AGM):
5.63%, 8/01/31		250		262,200
5.75%, 8/01/33		500		523,310
Hartnell Community College District California, GO, CAB, Election of 2002, Series D, 7.28%, 8/01/34 (b)		1,650		806,471
Norwalk-La Mirada Unified School District California, GO, Refunding, CAB, Election of 2002, Series E (AGC), 6.47%, 8/01/38 (a)		8,000		1,298,000
San Diego Community College District California, GO, CAB, Election of 2002, 6.18%, 8/01/19 (b)		2,800		1,732,304
State of California, GO, Refunding:
(CIFG), 4.50%, 8/01/28		2,000		1,757,400
Veterans, AMT 5.05%, 12/01/36		1,000		893,620
State of California, GO, Various Purpose:
5.75%, 4/01/31		2,000		2,048,240
6.50%, 4/01/33		1,950		2,105,357
University of California, RB, Limited Project, Series B, 4.75%, 5/15/38		910		875,729
Val Verde Unified School District California, Special Tax Bonds, Refunding, Junior Lien, 6.25%, 10/01/28		1,585		1,557,548
				21,622,845

Municipal Bonds	Par (000)		Value
Colorado — 1.2%
City of Colorado Springs Colorado, RB, Subordinate Lien, Improvement, Series C (AGM), 5.00%, 11/15/45	$	635	$	645,369
Colorado Health Facilities Authority, RB, Catholic Health Initiatives, Series D, 6.25%, 10/01/33		1,070		1,184,533
				1,829,902
District of Columbia — 8.3%
District of Columbia, Refunding RB, Friendship Public Charter School Inc. (ACA), 5.25%, 6/01/33		595		490,334
District of Columbia, Tax Allocation Bonds, Gallery Place Project (AGM), 5.40%, 7/01/31		6,000		6,096,720
District of Columbia Tobacco Settlement Financing Corp., Refunding RB, Asset-Backed, 6.75%, 5/15/40		5,580		5,590,602
				12,177,656
Florida — 7.4%
County of Miami-Dade, Florida, RB, Miami-Dade County Water & Sewer System, 5.00%, 10/01/34 (c)		1,600		1,595,424
Miami Beach Health Facilities Authority, RB, Mount Sinai Medical Center of Florida, 6.75%, 11/15/21		1,255		1,262,354
Palm Beach County Housing Finance Authority, HRB, Indian Trace Apartments, Series A, AMT (AGM), 5.63%, 1/01/44		7,255		7,294,177
Stevens Plantation Community Development District, Special Assessment Bonds, Series A, 7.10%, 5/01/35		955		735,398
				10,887,353
Georgia — 3.6%
City of Atlanta Georgia, RB (AGM), 5.00%, 11/01/37		3,000		3,002,250
Gainesville & Hall County Hospital Authority, RB, Northeast Georgia Healthcare, Series B, 5.00%, 2/15/33		2,000		1,962,460
Gwinnett County Hospital Authority, RB, Gwinnett Hospital System, Series C (AGM), 5.50%, 7/01/42		350		355,337
				5,320,047
Idaho — 1.8%
Idaho Health Facilities Authority, Refunding RB, Trinity Health Group, Series B, 6.25%, 12/01/33		1,750		1,921,763
Idaho Housing & Finance Association, RB, GAN, RAN, Federal Highway Trust, Series A, 5.00%, 7/15/27		600		642,660
				2,564,423
Illinois — 9.0%
Illinois Finance Authority, RB:
MJH Education Assistance IV, LLC, Sub-Series B, 5.38%, 6/01/35		425		106,254
Monarch Landing Inc. Facility, Series A, 7.00%, 12/01/37 (d)(e)		720		201,456
Roosevelt University Project, 6.50%, 4/01/44		1,000		1,033,800
Rush University Medical Center, Series C, 6.63%, 11/01/39		650		689,585
Illinois Finance Authority, Refunding RB, Series A:
Friendship Village Schaumburg, 5.63%, 2/15/37		210		166,049
Lake Forest Hospital, 5.75%, 7/01/29		6,000		6,115,320
Village of Bolingbrook Illinois, GO, Refunding, Series B (NPFGC), 6.22%, 1/01/36 (a)		23,065		4,775,147
				13,087,611
Iowa — 1.7%
Iowa Finance Authority, RB, Series A (AGC), 5.63%, 8/15/37		2,400		2,493,648

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	19

Schedule of Investments (continued)	BlackRock Municipal Bond Trust (BBK)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Kansas — 3.8%
Kansas Development Finance Authority, RB, University of Kansas Tenant, Series O, 4.75%, 6/15/41	$	1,350	$	1,292,679
Wichita Airport Authority, RB, Special, Cessna Citation Service Center, Series A, AMT, 6.25%, 6/15/32		5,000		4,302,750
				5,595,429
Kentucky — 0.4%
Kentucky Economic Development Finance Authority, RB, Louisville Arena, Sub-Series A-1 (AGC), 6.00%, 12/01/38		500		539,075
Maryland — 1.8%
County of Frederick Maryland, Special Tax Bonds, Urbana Community Development Authority, Sub-Series B, 6.25%, 7/01/30		2,820		2,688,842
Michigan — 5.0%
Michigan State Building Authority, Refunding RB, Facilities Program, Series I, 6.25%, 10/15/38		1,250		1,365,738
Michigan State Hospital Finance Authority, Refunding RB:
Henry Ford Health System, Series A, 5.25%, 11/15/46		1,065		944,964
Hospital, Henry Ford Health, 5.75%, 11/15/39		2,750		2,677,207
Royal Oak Hospital Finance Authority Michigan, Refunding RB, William Beaumont Hospital, 8.25%, 9/01/39		1,950		2,294,682
				7,282,591
Minnesota — 4.1%
City of Minneapolis Minnesota, Refunding RB, Fairview Health Services, Series B (AGC), 6.50%, 11/15/38		5,350		5,963,056
Mississippi — 3.1%
Mississippi Development Bank Special Obligation, RB, Jackson County Limited Tax Note (AGC), 5.50%, 7/01/32		1,750		1,838,585
University of Southern Mississippi, RB, Campus Facilities Improvements Project, 5.38%, 9/01/36		2,500		2,649,900
				4,488,485
Multi-State — 11.2%
Centerline Equity Issuer Trust, 7.20%, 10/31/52 (f)(g)		10,500		11,502,435
M/F Housing Revenue Bond Pass-Through Certificates, RB, AMT:
Series 1, Canterbury House Apartments, 5.90%, 12/01/34		1,865		1,895,045
Series 6, 6.05%, 11/01/34		525		531,237
Series 9, Copperwood Ranch Apartments, 5.95%, 11/01/35		2,460		2,510,283
				16,439,000
Nebraska — 0.1%
Omaha Public Power District, RB, Series A, 4.75%, 2/01/44		160		159,459
Nevada — 1.2%
City of Las Vegas Nevada, Special Assessment Bonds, Summerlin Area, 5.65%, 6/01/23		1,335		1,119,651
County of Clark Nevada, Refunding RB, Alexander Dawson School Nevada Project, 5.00%, 5/15/29		575		576,173
				1,695,824

Municipal Bonds	Par (000)		Value
New Jersey — 16.2%
Middlesex County Improvement Authority, RB,
Subordinate, Heldrich Center Hotel, Series B, 6.25%, 1/01/37	$	915	$	169,147
New Jersey EDA, RB:
Cigarette Tax, 5.50%, 6/15/24		3,710		3,659,136
Cigarette Tax (Radian), 5.50%, 6/15/31		1,500		1,410,330
Continental Airlines Inc. Project, AMT 7.20%, 11/15/30		3,000		2,927,130
Motor Vehicle Surcharge, Series A (NPFGC), 5.00%, 7/01/27		1,000		1,009,260
New Jersey EDA, Refunding RB, First Mortgage, Winchester, Series A, 5.80%, 11/01/31		1,500		1,474,440
New Jersey EDA, Special Assessment Bonds, Refunding, Kapkowski Road Landfill Project, 6.50%, 4/01/28		7,500		7,531,125
New Jersey Educational Facilities Authority, RB, Princeton University, Series B, 4.25%, 7/01/40		1,400		1,358,098
New Jersey Educational Facilities Authority, Refunding RB, University of Medicine & Dentistry, Series B:
7.13%, 12/01/23		630		720,688
7.50%, 12/01/32		800		903,664
New Jersey Health Care Facilities Financing Authority, RB, Virtua Health (AGC), 5.50%, 7/01/38		500		524,160
New Jersey State Housing & Mortgage Finance Agency, RB, Series AA, 6.50%, 10/01/38		930		1,016,267
University of Medicine & Dentistry of New Jersey, RB, Series A (AMBAC), 5.50%, 12/01/27		1,000		1,003,210
				23,706,655
New York — 9.7%
Albany Industrial Development Agency, RB, New Covenant Charter School Project, Series A, 7.00%, 5/01/35		455		227,500
Hudson Yards Infrastructure Corp., RB, Series A, 5.00%, 2/15/47		715		679,700
Long Island Power Authority, RB, General, Series C (CIFG), 5.25%, 9/01/29		1,500		1,655,415
Long Island Power Authority, Refunding RB, Series A, 6.25%, 4/01/33		300		345,108
Metropolitan Transportation Authority, Refunding RB, Series B, 5.00%, 11/15/34		800		832,432
New York City Housing Development Corp., RB, Series A, AMT, 5.50%, 11/01/34		3,000		3,018,690
New York City Industrial Development Agency, RB:
American Airlines Inc., JFK International Airport, AMT 7.75%, 8/01/31		3,165		3,164,715
Queens Baseball Stadium, PILOT (AGC), 6.50%, 1/01/46		700		769,545
New York Liberty Development Corp., RB, Goldman Sachs Headquarters, 5.25%, 10/01/35		500		504,695
New York State Dormitory Authority, RB:
5.83%, 7/01/39 (b)		700		568,029
Rochester Institute of Technology, Series A, 6.00%, 7/01/33		1,000		1,098,250
University of Rochester, Series A, 5.13%, 7/01/39		250		258,138
Port Authority of New York & New Jersey, Refunding RB, Consolidated, 152nd Series, AMT, 5.75%, 11/01/30		1,000		1,061,490
				14,183,707

See Notes to Financial Statements.
20	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (continued)	BlackRock Municipal Bond Trust (BBK)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
North Carolina — 2.8%
City of Charlotte North Carolina, Refunding RB, Series A, 5.50%, 7/01/34	$	225	$	237,710
Gaston County Industrial Facilities & Pollution Control Financing Authority, North Carolina, RB, Exempt Facilities, National Gypsum Co. Project, AMT, 5.75%, 8/01/35		2,945		1,901,881
North Carolina Medical Care Commission, RB, WakeMed, Series A (AGC), 5.88%, 10/01/38		1,000		1,038,810
North Carolina Medical Care Commission, Refunding RB, University Health System, Series D, 6.25%, 12/01/33		800		880,920
				4,059,321
Ohio — 2.1%
Kent State University, Refunding RB, General Receipts, Series B (AGC), 4.25%, 5/01/31		1,500		1,461,060
Ohio Higher Educational Facility Commission, Refunding RB, Kenyon College Project, 4.75%, 7/01/39		1,600		1,574,992
				3,036,052
Oklahoma — 1.2%
Tulsa Airports Improvement Trust, RB, Series A, AMT, 7.75%, 6/01/35		1,725		1,692,104
Oregon — 0.9%
Oregon Health & Science University, RB, Series A, 5.75%, 7/01/39		1,250		1,315,413
Pennsylvania — 1.0%
Pennsylvania Economic Development Financing Authority, RB, Reliant Energy, Series A, AMT, 6.75%, 12/01/36		1,455		1,449,442
Puerto Rico — 1.9%
Puerto Rico Sales Tax Financing Corp., RB, First Sub-Series A, 5.75%, 8/01/37		2,000		2,061,540
Puerto Rico Sales Tax Financing Corp., Refunding RB, CAB, Series A (NPFGC), 5.77%, 8/01/41 (a)		5,000		751,100
				2,812,640
Rhode Island — 2.4%
Rhode Island Health & Educational Building Corp., RB, Hospital Financing, LifeSpan Obligation, Series A (AGC), 7.00%, 5/15/39		1,000		1,145,080
Rhode Island Housing & Mortgage Finance Corp., RB, Homeownership Opportunity, Series 54, AMT, 4.85%, 10/01/41		1,500		1,403,055
State of Rhode Island, COP, Series C, School for the Deaf (AGC), 5.38%, 4/01/28		900		956,835
				3,504,970
Tennessee — 0.4%
Memphis-Shelby County Sports Authority Inc., Refunding RB, Memphis Arena Project, Series A, 5.38%, 11/01/28		525		540,734

Municipal Bonds	Par (000)		Value
Texas — 14.7%
Harris County Health Facilities Development Corp., Refunding RB, Memorial Hermann Healthcare System, Series B:
7.13%, 12/01/31	$	500	$	561,390
7.25%, 12/01/35		1,750		1,964,375
Harris County-Houston Sports Authority, Texas, Refunding RB, CAB, Senior Lien, Series G (NPFGC), 6.17%, 11/15/41 (a)		11,690		1,173,559
Lower Colorado River Authority, Refunding RB (NPFGC), 5.00%, 5/15/13 (h)		15		16,868
Matagorda County Navigation District No. 1, Texas, Refunding RB, Central Power & Light Co. Project, Series A, 6.30%, 11/01/29		1,500		1,627,890
San Antonio Energy Acquisition Public Facility Corp., RB, Gas Supply:
5.50%, 8/01/23		1,775		1,843,356
5.50%, 8/01/24		1,620		1,688,931
Texas State Turnpike Authority, RB (AMBAC):
CAB, 6.08%, 8/15/35 (a)		60,000		10,687,200
First Tier, Series A, 5.00%, 8/15/42		2,115		2,001,509
				21,565,078
Washington — 1.0%
Washington Health Care Facilities Authority, RB, MultiCare Health System, Series B (AGC), 6.00%, 8/15/39		1,400		1,483,314
West Virginia — 2.4%
West Virginia Higher Education Policy Commission, RB, Community & Technology Capital Improvement, Series A:
4.75%, 7/01/33		650		641,830
5.00%, 7/01/39		850		842,188
West Virginia Hospital Finance Authority, Refunding RB, Charleston, Series A, 5.63%, 9/01/32		2,000		1,976,100
				3,460,118
Wisconsin — 1.8%
Wisconsin Health & Educational Facilities Authority, RB, Aurora Health Care, 6.40%, 4/15/33		1,350		1,376,285
Wisconsin Housing & EDA, Refunding RB, Series A, AMT, 4.75%, 9/01/33		1,340		1,274,407
				2,650,692
Wyoming — 0.9%
County of Sweetwater Wyoming, Refunding RB, Idaho Power Co. Project, 5.25%, 7/15/26		1,200		1,248,240
Total Municipal Bonds — 147.2%				215,183,138

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	21

Schedule of Investments (concluded)	BlackRock Municipal Bond Trust (BBK)
	(Percentages shown are based on Net Assets)

Municipal Bonds Transferred to Tender Option Bond Trusts (i)	Par (000)		Value
Colorado — 2.5%
Colorado Health Facilities Authority, RB, Catholic Health, Series C-7 (AGM), 5.00%, 9/01/36	$	3,750	$	3,728,175
Massachusetts — 1.0%
Massachusetts Water Resources Authority, RB, General, Series A, 5.00%, 8/01/41		1,450		1,477,071
New York — 2.2%
New York City Municipal Water Finance Authority, RB:
Fiscal 2009, Series A, 5.75%, 6/15/40		450		503,342
Series FF-2, 5.50%, 6/15/40		405		444,732
New York State Dormitory Authority, RB, New York University, Series A, 5.00%, 7/01/38		2,199		2,270,455
				3,218,529
Ohio — 2.3%
County of Montgomery, Ohio, RB, Catholic Health, Series C-1 (AGM), 5.00%, 10/01/41		1,260		1,236,388
Ohio Higher Educational Facility Commission, Refunding RB, Hospital, Cleveland Clinic Health, Series A, 5.25%, 1/01/33		2,000		2,056,820
				3,293,208
Total Municipal Bonds Transferred to Tender Option Bond Trusts — 8.0%				11,716,983
Total Long-Term Investments (Cost — $226,900,380) — 155.2%				226,900,121
Short-Term Securities		Shares
FFI Institutional Tax-Exempt Fund, 0.16% (j)(k)		4,158,073		4,158,073
Total Short-Term Securities (Cost — $4,158,073) — 2.9%				4,158,073
Total Investments (Cost — $231,058,453*) — 158.1%				231,058,194
Other Assets Less Liabilities — 0.6%				927,135
Liability for Trust Certificates, Including Interest Expense and Fees Payable — (4.0)%				(5,903,084	)
Preferred Shares, at Redemption Value — (54.7)%				(79,902,974	)
Net Assets Applicable to Common Shares — 100.0%			$	146,179,271

* The cost and unrealized appreciation (depreciation) of investments as of February 28, 2010, as computed for federal income tax purposes, were as follows:

Aggregate cost	$	224,417,008
Gross unrealized appreciation	$	9,291,972
Gross unrealized depreciation		(8,549,934	)
Net unrealized appreciation	$	742,038

(a)	Represents a zero-coupon bond. Rate shown reflects the current yield as of report date.
(b)	Represents a step-up bond that pays an initial coupon rate for the first period and then a higher coupon rate for the following periods. Rate shown reflects the current yield as of report date.
(c)	When-issued security. Unsettled when-issued security transactions were as follows:

Counterparty	Value		Unrealized Appreciation
Raymond C. Forbes & Co., Inc.	$	1,595,424	$	6,672

(d)	Issuer filed for bankruptcy and/or is in default of interest payments.
(e)	Non-income producing security.
(f)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration to qualified institutional investors.
(g)	Security represents a beneficial interest in a trust. The collateral deposited into the trust is federally tax-exempt revenue bonds issued by various state or local governments, or their respective agencies or authorities. The security is subject to remarketing prior to its stated maturity, and is subject to mandatory redemption at maturity.
(h)	US 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.
(i)	Securities represent bonds transferred to a tender option bond trust in exchange for which the Trust 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.
(j)	Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:

Affiliate	Net Activity		Income
FFI Institutional Tax-Exempt Fund	$	757,355	$	2,049

(k)	Represents the current yield as of report date.
•	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 assets and liabilities
	•	Level 2 — other observable inputs (including, but not limited to: quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)
	•	Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Trust’s own assumptions used in determining the fair value of investments)
	The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in those securities. For information about the Trust’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 February 28, 2010 in determining the fair valuation of the Trust’s investments:

Valuation Inputs	Level 1		Level 2		Level 3		Total
Assets:
Long-Term Investments1		—	$	226,900,121		—	$	226,900,121
Short-Term Securities	$	4,158,073		—		—		4,158,073
Total	$	4,158,073	$	226,900,121		—	$	231,058,194

¹ See above Schedule of Investments for values in each state or political subdivision.

See Notes to Financial Statements.
22	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments February 28, 2010 (Unaudited)	BlackRock Municipal Bond Investment Trust (BIE)
	(Percentages shown are based on Net Assets)

Municipal Bonds		Par (000)	Value
Arizona — 0.7%
Pima County IDA, Refunding IDRB, Tucson Electric Power, 5.75%, 9/01/29	$	330	$	333,043
California — 16.4%
Bay Area Toll Authority, Refunding RB, San Francisco Bay Area, Series F-1, 5.63%, 4/01/44		720		767,707
California Health Facilities Financing Authority, Refunding RB:
Catholic Healthcare West, Series A, 6.00%, 7/01/39		120		125,400
St. Joseph Health System, Series A, 5.75%, 7/01/39		730		753,367
California State Public Works Board, RB:
Department of General Services, Buildings 8 & 9, Series A, 6.25%, 4/01/34		1,100		1,123,628
Various Capital Projects, Sub-Series I-1, 6.38%, 11/01/34		340		350,860
Los Angeles Department of Water & Power, RB, Power System, Sub-Series A-1, 5.25%, 7/01/38		1,500		1,594,650
San Diego Public Facilities Financing Authority, Refunding RB, Series B, 5.50%, 8/01/39		2,235		2,364,630
San Diego Regional Building Authority California, RB, County Operations Center & Annex, Series A, 5.38%, 2/01/36		850		885,131
				7,965,373
Colorado — 3.6%
City & County of Denver Colorado, Refunding RB, Series A, 5.25%, 11/15/36		1,095		1,125,124
Colorado Health Facilities Authority, Refunding RB, Catholic Healthcare, Series A, 5.50%, 7/01/34		580		614,736
				1,739,860
District of Columbia — 1.4%
District of Columbia Water & Sewer Authority, RB, Series A, 5.25%, 10/01/29		640		683,283
Florida — 21.1%
City of Palm Bay Florida, RB, Improvement (NPFGC), 5.68%, 10/01/28 (a)		1,610		572,613
County of Miami-Dade Florida, RB, Sub-Series B (NPFGC) (a):
5.91%, 10/01/30		10,000		2,532,600
5.78%, 10/01/32		5,410		1,183,437
County of St. John’s Florida, RB, CAB (AMBAC), 5.40%, 6/01/32 (a)		1,370		387,107
Florida Municipal Loan Council, Refunding RB, Series A (NPFGC), 5.13%, 5/01/32		3,050		3,055,520
Hillsborough County Aviation Authority Florida, Refunding RB, Series D (AGC), 5.50%, 10/01/26		475		521,313
Miami Beach Health Facilities Authority, RB, Mount Sinai Medical Center of Florida, 6.75%, 11/15/21		420		422,461
New River Community Development District, Special Assessment Bonds, Series B, 5.00%, 5/01/13 (b)(c)		750		299,925
Volusia County Educational Facility Authority, Refunding RB, Embry-Riddle Aeronautical University (Radian), 5.20%, 10/15/33		1,410		1,271,665
				10,246,641
Georgia — 5.1%
Metropolitan Atlanta Rapid Transit Authority, RB, Third Series, 5.00%, 7/01/39		1,300		1,351,090
Municipal Electric Authority of Georgia, Refunding RB, Project One, Sub-Series D, 6.00%, 1/01/23		1,000		1,140,690
				2,491,780

Municipal Bonds		Par (000)	Value
Illinois — 3.8%
Illinois Finance Authority, Refunding RB, Northwestern Memorial Hospital, Series A, 6.00%, 8/15/39	$	1,000	$	1,100,030
State of Illinois, RB, Build Illinois, Series B, 5.25%, 6/15/34		730		751,053
				1,851,083
Indiana — 2.6%
Indiana Municipal Power Agency, RB, Indiana Municipal Power Agency, Series B, 6.00%, 1/01/39		1,190		1,274,157
Kansas — 1.9%
Kansas Development Finance Authority, Refunding RB, Adventist Health, 5.50%, 11/15/29		900		949,122
Kentucky — 4.2%
Kentucky Economic Development Finance Authority, Refunding RB, Owensboro Medical Health System, Series A, 6.38%, 6/01/40 (d)		350		348,792
Louisville & Jefferson County Metropolitan Government Parking Authority, RB, Series A, 5.75%, 12/01/34		800		874,280
Louisville & Jefferson County Metropolitan Government, Refunding RB, Jewish Hospital & St. Mary’s HealthCare, 6.13%, 2/01/37		775		800,730
				2,023,802
Massachusetts — 4.8%
Massachusetts Health & Educational Facilities Authority, RB, Tufts University, 5.38%, 8/15/38		500		538,915
Massachusetts Health & Educational Facilities Authority, Refunding RB, Partners Healthcare System, Series B, 5.25%, 7/01/29		1,500		1,513,485
Massachusetts State College Building Authority, RB, Series A, 5.50%, 5/01/39		250		262,285
				2,314,685
Michigan — 2.4%
Michigan State Building Authority, Refunding RB, Facilities Program, Series I, 6.00%, 10/15/38		500		537,585
Royal Oak Hospital Finance Authority Michigan, Refunding RB, William Beaumont Hospital, 8.25%, 9/01/39		530		623,683
				1,161,268
Multi-State — 6.8%
Centerline Equity Issuer Trust, 7.20%, 10/31/52 (e)(f)		3,000		3,286,410
Nevada — 5.7%
City of Las Vegas Nevada, GO, Limited Tax, Performing Arts Center, 6.00%, 4/01/34		1,000		1,099,170
County of Clark Nevada, RB, Series B, 5.75%, 7/01/42		1,630		1,697,009
				2,796,179
New Jersey — 4.5%
New Jersey EDA, Refunding RB, School Facilities Construction, Series AA, 5.50%, 12/15/29		750		814,762
New Jersey State Housing & Mortgage Finance Agency, RB, S/F Housing, Series CC, 5.25%, 10/01/29		620		638,960
New Jersey Transportation Trust Fund Authority, RB, Transportation System, Series A, 5.88%, 12/15/38		695		757,974
				2,211,696
New York — 6.2%
New York City Transitional Finance Authority, RB, Fiscal 2009, Series S-3, 5.25%, 1/15/39		1,000		1,046,920
New York State Dormitory Authority, ERB, Series B, 5.25%, 3/15/38		1,000		1,061,350
Triborough Bridge & Tunnel Authority, RB, General, Series A-2, 5.38%, 11/15/38		840		901,236
				3,009,506

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	23

Schedule of Investments (continued)	BlackRock Municipal Bond Investment Trust (BIE)
	(Percentages shown are based on Net Assets)

Municipal Bonds		Par (000)	Value
North Carolina — 2.3%
City of Charlotte North Carolina, Refunding RB, Series A, 5.50%, 7/01/34	$	95	$	100,367
North Carolina Eastern Municipal Power Agency, Refunding RB, Series B, 5.00%, 1/01/26		1,000		1,033,890
				1,134,257
Pennsylvania — 3.9%
Pennsylvania Economic Development Financing Authority, RB, American Water Co. Project, 6.20%, 4/01/39		300		322,860
Pennsylvania Turnpike Commission, RB:
Sub-Series B, 5.25%, 6/01/39		1,000		1,019,020
Sub-Series C (AGC), 6.25%, 6/01/38		500		565,145
				1,907,025
Texas — 7.1%
City of Houston Texas, RB, Senior Lien, Series A, 5.50%, 7/01/39		315		336,020
Conroe ISD Texas, GO, School Building, Series A, 5.75%, 2/15/35		470		506,364
Harris County Health Facilities Development Corp., Refunding RB, Memorial Hermann Healthcare System, B, 7.13%, 12/01/31		250		280,695
Lower Colorado River Authority, RB, 5.75%, 5/15/28		450		476,946
North Texas Tollway Authority, RB, System, First Tier, Series K-1 (AGC), 5.75%, 1/01/38		750		811,492
Texas Private Activity Bond Surface Transportation Corp., RB, Senior Lien, Note Mobility, 6.88%, 12/31/39		1,000		1,034,920
				3,446,437
Utah — 1.3%
City of Riverton Utah, RB, IHC Health Services Inc., 5.00%, 8/15/41		640		642,867
Virginia — 2.7%
Virginia Public School Authority, RB, School Financing, 6.50%, 12/01/35		750		861,683
Virginia Small Business Financing Authority, Refunding RB, Sentara Healthcare, 5.00%, 11/01/40		445		448,502
				1,310,185
Wisconsin — 1.8%
Wisconsin Health & Educational Facilities Authority, Refunding RB, Froedtert & Community Health Inc., 5.25%, 4/01/39		890		894,423
Wyoming — 1.4%
County of Sweetwater Wyoming, Refunding RB, Idaho Power Co. Project, 5.25%, 7/15/26		655		681,331
Total Municipal Bonds — 111.7%				54,354,413
Municipal Bonds Transferred to Tender Option Bond Trusts (g)
California — 9.2%
California Educational Facilities Authority, RB, University of Southern California, Series A, 5.25%, 10/01/18		1,005		1,067,772
Los Angeles Community College District California, GO, Election of 2008, Series A, 6.00%, 8/01/33		2,079		2,309,854
Los Angeles Unified School District California, GO, Series I, 5.00%, 1/01/34		200		200,580
University of California, RB, Series O, 5.75%, 5/15/34		810		900,517
				4,478,723

Municipal Bonds Transferred to Tender Option Bond Trusts (g)		Par (000)	Value
District of Columbia — 3.7%
District of Columbia, RB, Series A, 5.50%, 12/01/30	$	735	$	823,979
District of Columbia Water & Sewer Authority, RB, Series A, 5.50%, 10/01/39		899		962,897
				1,786,876
Florida — 8.4%
Jacksonville Economic Development Commission, RB, Mayo Clinic Jacksonville, Series B, 5.50%, 11/15/36		3,510		3,582,412
Jacksonville Electric Authority Florida, RB, Issue Three, Series Two, River Power Pike, 5.00%, 10/01/37		510		513,177
				4,095,589
Illinois — 7.9%
Illinois Finance Authority, RB, University of Chicago, Series B, 6.25%, 7/01/38		1,500		1,697,610
Illinois State Toll Highway Authority, RB, Series B, 5.50%, 1/01/33		1,999		2,141,453
				3,839,063
Nevada — 3.4%
Clark County Water Reclamation District, GO, Limited Tax, 6.00%, 7/01/38		1,500		1,667,160
New Hampshire — 1.3%
New Hampshire Health & Education Facilities Authority, Refunding RB, Dartmouth College, 5.25%, 6/01/39		585		630,478
New York — 4.0%
New York City Municipal Water Finance Authority, RB:
Fiscal 2009, Series A, 5.75%, 6/15/40		750		838,904
Series FF-2, 5.50%, 6/15/40		990		1,087,122
				1,926,026
South Carolina — 2.2%
South Carolina State Public Service Authority, RB, Santee Cooper, Series A, 5.50%, 1/01/38		1,005		1,085,229
Texas — 5.4%
City of San Antonio, Texas, Refunding RB, Series A, 5.25%, 2/01/31		1,050		1,139,274
Harris County Cultural Education Facilities Finance Corporation, RB, Hospital Texas Childrens Hospital Project, 5.50%, 10/01/39		1,450		1,495,733
				2,635,007
Virginia — 1.0%
Fairfax County IDA Virginia, Refunding RB, Health Care, Inova Health System, Series A, 5.50%, 5/15/35		460		480,263
Total Municipal Bonds Transferred to Tender Option Bond Trusts — 46.5%				22,624,414
Total Long-Term Investments (Cost — $74,773,026) — 158.2%				76,978,827
Short-Term Securities		Shares
FFI Institutional Tax Exempt Fund, 0.16% (h)(i)		956,848		956,848
Total Short-Term Securities (Cost — $956,848) — 2.0%				956,848
Total Investments (Cost — $75,729,874*) — 160.2%				77,935,675
Other Assets Less Liabilities– 0.8%				404,576
Liability for Trust Certificates, Including Interest Expense and Fees Payable — (24.3)%				(11,827,674	)
Preferred Shares, at Redemption Value — (36.7)%				(17,850,626	)
Net Assets Applicable to Common Shares — 100.0%			$	48,661,951

See Notes to Financial Statements.
24	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (concluded) BlackRock Municipal Bond Investment Trust (BIE)

* The cost and unrealized appreciation (depreciation) of investments as of February 28, 2010, as computed for federal income tax purposes, were as follows:

Aggregate cost	$	63,979,898
Gross unrealized appreciation	$	3,680,886
Gross unrealized depreciation		(1,546,856	)
Net unrealized appreciation	$	2,134,030

(a)	Represents a zero-coupon bond. Rate shown reflects the current yield as of report date.
(b)	Issuer filed for bankruptcy and/or is in default of interest payments.
(c)	Non-income producing security.
(d)	When-issued security. Unsettled when-issued transactions were as follows:

Counterparty	Value		Unrealized Appreciation
Merrill Lynch & Co., Inc.	$	348,792	$	10,206

(e)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration to qualified institutional investors.
(f)	Security represents a beneficial interest in a trust. The collateral deposited into the trust is federally tax-exempt revenue bonds issued by various state or local governments, or their respective agencies or authorities. The security is subject to remarketing prior to its stated maturity, and is subject to mandatory redemption at maturity.
(g)	Securities represent bonds transferred to a tender option bond trust in exchange for which the Trust 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.
(h)	Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:

Affiliate	Net Activity			Income
CMA Florida Municipal Money Fund	$	(2	)		—
FFI Institutional Tax-Exempt Fund	$	956,848		$	1,887

(i)	Represents the current yield as of report date.
•	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 assets and liabilities
	•	Level 2 — other observable inputs (including, but not limited to: quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)
	•	Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Trust’s own assumptions used in determining the fair value of investments)
	The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in those securities. For information about the Trust’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 February 28, 2010 in determining the fair valuation of the Trust’s investments:

	Investment in Securities
Valuation Inputs	Level 1		Level 2		Level 3		Total
Assets:
Long-Term Investments1		—	$	76,978,827		—	$	76,978,827
Short-Term Securities	$	956,848		—		—		956,848
Total	$	956,848	$	76,978,827		—	$	77,935,675

¹ See above Schedule of Investments for values in each state or political subdivision.

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	25

Schedule of Investments February 28, 2010 (Unaudited)	BlackRock Municipal Income Trust II (BLE)
	(Percentages shown are based on Net Assets)

Municipal Bonds		Par (000)	Value
Arizona — 4.7%
Pima County IDA, RB, American Charter Schools Foundation, Series A, 5.63%, 7/01/38	$	2,525	$	1,957,304
Pima County IDA, Refunding IDRB, Tucson Electric Power, 5.75%, 9/01/29		1,210		1,221,156
Salt River Project Agricultural Improvement & Power District, RB, Series A, 5.00%, 1/01/38		2,135		2,211,945
Salt Verde Financial Corp., RB, Senior:
5.00%, 12/01/32		5,635		4,927,188
5.00%, 12/01/37		5,270		4,485,930
				14,803,523
California — 20.6%
Bay Area Toll Authority, Refunding RB, San Francisco Bay Area, Series F-1, 5.63%, 4/01/44		2,480		2,644,325
California County Tobacco Securitization Agency, RB, CAB, Stanislaus, Sub-Series C, 6.30%, 6/01/55 (a)		9,710		121,375
California HFA, RB, AMT:
Home Mortgage, Series G, 5.50%, 8/01/42		8,930		9,504,913
Home Mortgage, Series K, 5.50%, 2/01/42		3,195		3,393,026
California State Public Works Board, RB, Various Capital Projects, Sub-Series I-1, 6.38%, 11/01/34		1,280		1,320,883
California Statewide Communities Development Authority, RB, Health Facility, Memorial Health Services, Series A, 5.50%, 10/01/33		5,000		5,032,200
Los Angeles Department of Airports, RB, Series A, 5.25%, 5/15/39		860		869,959
Los Angeles Unified School District California, GO:
Series D, 5.00%, 7/01/27		2,375		2,481,257
Series I, 5.00%, 7/01/26		1,250		1,317,688
Series I, 5.00%, 7/01/27		1,750		1,828,295
San Francisco City & County Public Utilities Commission, RB, Series B, 5.00%, 11/01/39		10,340		10,610,701
San Francisco City & County Redevelopment Agency, Special Tax Bonds, District No. 6, Mission Bay South Public Improvements, 6.63%, 8/01/27		3,120		3,140,935
State of California, GO, Refunding, Various Purpose, 5.00%, 6/01/34		2,700		2,469,528
State of California, GO, Various Purpose:
5.00%, 6/01/32		3,800		3,507,020
6.50%, 4/01/33		10,670		11,520,079
University of California, RB, Limited Project, Series B, 4.75%, 5/15/38		5,705		5,490,150
				65,252,334
Colorado — 1.6%
City of Colorado Springs Colorado, RB, Subordinate Lien, Improvement, Series C (AGM), 5.00%, 11/15/45		1,375		1,397,454
Colorado Health Facilities Authority, Refunding RB, Catholic Healthcare, Series A, 5.50%, 7/01/34		2,330		2,469,544
Park Creek Metropolitan District Colorado, Refunding RB, Senior, Limited Tax, Property Tax, 5.50%, 12/01/37		1,375		1,272,012
				5,139,010
District of Columbia — 6.8%
District of Columbia, Refunding RB, Friendship Public Charter School Inc. (ACA), 5.25%, 6/01/33		1,265		1,042,474
District of Columbia Tobacco Settlement Financing Corp., Refunding RB, Asset-Backed:
6.50%, 5/15/33		7,500		7,410,525
6.75%, 5/15/40		11,500		11,521,850

Municipal Bonds		Par (000)	Value
District of Columbia (concluded)
Metropolitan Washington Airports Authority, RB, First Senior Lien, Series A:
5.00%, 10/01/39	$	550	$	558,778
5.25%, 10/01/44		865		891,261
				21,424,888
Florida — 6.6%
City of Leesburg Florida, RB, Leesburg Regional Medical Center Project, 5.50%, 7/01/32		2,650		2,418,072
County of Miami-Dade Florida, RB, Miami International Airport, Series A, AMT (AGC), 5.25%, 10/01/38		2,855		2,788,764
County of Miami-Dade Florida, Refunding RB, Miami International Airport, Series A-1, 5.38%, 10/01/41		1,255		1,260,472
County of Orange Florida, Refunding RB (Syncora), 4.75%, 10/01/32		1,140		1,113,689
Live Oak Community Development District No. 1, Special Assessment Bonds, Series A, 6.30%, 5/01/34		3,115		3,162,535
Miami Beach Health Facilities Authority, RB, Mount Sinai Medical Center of Florida, 6.75%, 11/15/21		4,145		4,169,290
Stevens Plantation Community Development District, Special Assessment Bonds, Series A, 7.10%, 5/01/35		1,985		1,528,549
Sumter County IDA Florida, RB, North Sumter Utility Co. LLC Project, AMT, 6.90%, 10/01/34		4,340		4,278,979
				20,720,350
Georgia — 1.5%
De Kalb Private Hospital Authority, Refunding RB, Children’s Healthcare, 5.25%, 11/15/39		915		923,949
Metropolitan Atlanta Rapid Transit Authority, RB, Third Series, 5.00%, 7/01/39		3,770		3,918,161
				4,842,110
Guam — 1.1%
Territory of Guam, GO, Series A:
6.00%, 11/15/19		695		716,865
6.75%, 11/15/29		1,220		1,288,344
7.00%, 11/15/39		1,260		1,343,778
				3,348,987
Illinois — 6.0%
Illinois Finance Authority, RB (b)(c):
MJH Education Assistance IV LLC, Sub-Series B, 5.38%, 6/01/35		900		225,009
Monarch Landing Inc. Facility, Series A, 7.00%, 12/01/37		1,585		443,483
Illinois Finance Authority, Refunding RB:
Central DuPage Health, Series B, 5.50%, 11/01/39		1,750		1,816,360
Friendship Village Schaumburg, Series A, 5.63%, 2/15/37		455		359,773
Illinois Municipal Electric Agency, RB (NPFGC), 4.50%, 2/01/35		555		516,433
Illinois Sports Facilities Authority, RB, State Tax Supported (AMBAC), 5.57%, 6/15/30 (d)		15,000		14,993,400
State of Illinois, RB, Build Illinois, Series B, 5.25%, 6/15/34		685		704,755
				19,059,213

See Notes to Financial Statements.
26	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (continued)	BlackRock Municipal Income Trust II (BLE)
	(Percentages shown are based on Net Assets)

Municipal Bonds		Par (000)	Value
Indiana — 2.5%
Indiana Finance Authority, RB, Sisters of St. Francis Health, 5.25%, 11/01/39	$	915	$	930,207
Indiana Finance Authority, Refunding RB, Duke Energy Indiana Inc., Series C, 4.95%, 10/01/40		3,580		3,499,235
Indiana Health Facility Financing Authority, Refunding RB, Ascension Health, Series F, 5.38%, 11/15/25		2,095		2,173,479
Indiana Municipal Power Agency, RB, Indiana Municipal Power Agency, Series B, 6.00%, 1/01/39		1,200		1,284,864
				7,887,785
Kentucky — 0.4%
Kentucky Economic Development Finance Authority, Refunding RB, Owensboro Medical Health System, Series A, 6.38%, 6/01/40 (e)		1,105		1,101,188
Maryland — 0.5%
Maryland EDC, RB, Transportation Facilities Project, Series A, 5.75%, 6/01/35		475		483,802
Maryland Health & Higher Educational Facilities Authority, RB, Union Hospital of Cecil County Issue, 5.63%, 7/01/32		1,000		1,009,420
				1,493,222
Massachusetts — 0.6%
Massachusetts Health & Educational Facilities Authority, Refunding RB, Partners Healthcare, Series J1, 5.00%, 7/01/39		1,955		1,945,929
Michigan — 0.6%
Michigan State Hospital Finance Authority, Refunding RB, Henry Ford Health System, Series A, 5.25%, 11/15/46		2,305		2,045,203
Missouri — 1.7%
370 Missouri Bottom Road Taussig Road, Transportation Development District, RB, 7.20%, 5/01/33		6,000		5,489,340
Multi-State — 4.1%
Centerline Equity Issuer Trust (f)(g):
5.75%, 5/15/15		1,000		1,043,070
6.00%, 5/15/15		5,000		5,196,600
6.00%, 5/15/19		3,500		3,651,130
6.30%, 5/15/19		3,000		3,143,220
				13,034,020
Nevada — 0.8%
County of Clark Nevada, Refunding RB, Alexander Dawson School Nevada Project, 5.00%, 5/15/29		2,465		2,470,029
New Jersey — 12.2%
New Jersey EDA, RB:
Cigarette Tax, 5.75%, 6/15/34		3,810		3,655,733
Cigarette Tax (Radian), 5.50%, 6/15/31		8,235		7,742,712
Continental Airlines Inc. Project, AMT 7.20%, 11/15/30		10,100		9,854,671
Kapkowski Road Landfill Project, Series 1998B, AMT 6.50%, 4/01/31		10,000		9,919,900
New Jersey EDA, Special Assessment Bonds, Refunding, Kapkowski Road Landfill Project, 6.50%, 4/01/28		7,475		7,506,021
				38,679,037

Municipal Bonds		Par (000)	Value
New Mexico — 1.9%
New Mexico Income Housing Authority, RB, Villa Del Oso Apartments Project, Series A, 6.00%, 1/01/13 (h)	$	5,200	$	6,048,380
New York — 3.6%
Albany Industrial Development Agency, RB, New Covenant Charter School Project, Series A, 7.00%, 5/01/35		985		492,500
New York City Industrial Development Agency, RB, American Airlines Inc., JFK International Airport, AMT, 7.75%, 8/01/31		6,700		6,699,397
New York Liberty Development Corp., RB, Goldman Sachs Headquarters, 5.25%, 10/01/35		2,210		2,230,752
Port Authority of New York & New Jersey, RB, Continental Airlines Inc. and Eastern Air Lines Inc. Project, LaGuardia, AMT, 9.00%, 12/01/10		2,075		2,077,573
				11,500,222
North Carolina — 2.9%
City of Charlotte North Carolina, RB, Series B:
5.00%, 7/01/38		1,025		1,096,740
4.50%, 7/01/39		500		496,750
Gaston County Industrial Facilities & Pollution Control Financing Authority North Carolina, RB, Exempt Facilities, National Gypsum Co. Project, AMT, 5.75%, 8/01/35		7,500		4,843,500
North Carolina Eastern Municipal Power Agency, Refunding RB, Series B, 5.00%, 1/01/26		445		460,081
North Carolina Medical Care Commission, RB, Duke University Health System, Series A:
5.00%, 6/01/39		685		694,076
5.00%, 6/01/42		1,525		1,535,004
				9,126,151
Ohio — 1.3%
Buckeye Tobacco Settlement Financing Authority, RB, Asset-Backed, Senior Series A-2, 6.50%, 6/01/47		1,190		978,680
County of Montgomery Ohio, Refunding RB, Catholic Healthcare, Series A, 5.00%, 5/01/39		3,025		3,040,276
				4,018,956
Oklahoma — 1.2%
Tulsa Airports Improvement Trust, RB, Series A, AMT, 7.75%, 6/01/35		3,925		3,850,150
Pennsylvania — 7.3%
Allegheny County Hospital Development Authority, Refunding RB, Health System, West Penn, Series A, 5.38%, 11/15/40		2,765		2,073,335
Monroe County Hospital Authority Pennsylvania, RB, Hospital, Pocono Medical Center, 6.00%, 1/01/14 (h)		5,000		5,831,850
Pennsylvania Economic Development Financing Authority, RB:
Amtrak Project, Series A, AMT, 6.38%, 11/01/41		5,175		5,232,494
Aqua Pennsylvania Inc. Project, 5.00%, 11/15/40		2,065		2,075,903
Reliant Energy, Series A, AMT 6.75%, 12/01/36		6,130		6,106,584
Pennsylvania Turnpike Commission, RB, Sub-Series D, 5.13%, 12/01/40		1,700		1,717,442
				23,037,608

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	27

Schedule of Investments (continued)	BlackRock Municipal Income Trust II (BLE)
	(Percentages shown are based on Net Assets)

Municipal Bonds		Par (000)	Value
Puerto Rico — 7.5%
Commonwealth of Puerto Rico, GO, Refunding, Public Improvement, Series C, 6.00%, 7/01/39	$	3,220	$	3,305,394
Puerto Rico Sales Tax Financing Corp., RB:
CAB, Series A, 6.48%, 8/01/31 (a)		11,700		2,939,976
CAB, Series A, 6.57%, 8/01/33 (a)		13,600		2,968,880
CAB, Series A, 6.63%, 8/01/36 (a)		12,875		2,267,288
First Sub-Series A, 6.50%, 8/01/44		6,100		6,599,834
Puerto Rico Sales Tax Financing Corporation, RB, Capital Appreciation, Series A (a):
6.54%, 8/01/32		8,600		2,019,022
6.60%, 8/01/34		5,500		1,117,435
6.60%, 8/01/35		14,055		2,656,254
				23,874,083
South Carolina — 3.1%
County of Greenwood South Carolina, RB, Facilities, Self Memorial Hospital:
5.50%, 10/01/26		3,280		3,292,956
5.50%, 10/01/31		3,250		3,251,267
South Carolina Jobs-EDA, Refunding RB:
Palmetto Health Alliance, Series A, 6.25%, 8/01/31		2,640		2,678,782
Palmetto Health, Series C, 6.88%, 8/01/13 (h)		550		655,430
				9,878,435
Tennessee — 3.6%
Knox County Health Educational & Housing Facilities Board Tennessee, Refunding RB, CAB, Series A (AGM), 5.77%, 1/01/21 (a)		20,405		11,360,076
Texas — 19.5%
Brazos River Authority, RB, TXU Electric, Series A, AMT, 8.25%, 10/01/30		2,400		1,635,168
Brazos River Authority, Refunding RB, VRDN, TXU Electric Co. Project, Series C, AMT, 5.75%, 5/01/36		2,400		2,275,632
City of Houston Texas, RB, Senior Lien, Series A, 5.50%, 7/01/39		1,675		1,786,773
City of Houston Texas, Refunding RB, Combined, First Lien, Series A (AGC), 6.00%, 11/15/35		9,145		10,369,515
Gulf Coast Waste Disposal Authority, Refunding RB, Series A, AMT, 6.10%, 8/01/24		10,000		9,886,200
Harris County-Houston Sports Authority, Texas, Refunding RB, Third Lien, Series A-3 (NPFGC), 5.96%, 11/15/36 (a)		25,375		3,688,002
Lower Colorado River Authority, Refunding RB (NPFGC):
5.00%, 5/15/13 (h)		65		73,024
5.00%, 5/15/31		1,235		1,244,028
Series A, 5.00%, 5/15/13 (h)		5		5,623
North Texas Tollway Authority, RB, Toll, 2nd Tier, Series F, 6.13%, 1/01/31		6,790		7,099,149
San Antonio Energy Acquisition Public Facility Corp., RB, Gas Supply, 5.50%, 8/01/24		3,600		3,753,180
Texas Private Activity Bond Surface Transportation Corp., RB, Senior Lien, Note Mobility, 6.88%, 12/31/39		4,200		4,346,664
Texas State Turnpike Authority, RB (AMBAC):
CAB, 6.08%, 8/15/36 (a)		35,000		5,781,300
CAB, 6.09%, 8/15/37 (a)		10,000		1,530,900
CAB, 6.09%, 8/15/38 (a)		27,100		3,843,051
First Tier, Series A, 5.00%, 8/15/42		4,500		4,258,530
				61,576,739
Utah — 1.3%
City of Riverton Utah, RB, IHC Health Services Inc., 5.00%, 8/15/41		3,960		3,977,741

Municipal Bonds		Par (000)	Value
Virginia — 3.4%
City of Norfolk Virginia, Refunding RB, Series B (AMBAC), 5.50%, 2/01/31	$	1,460	$	1,424,507
Halifax County IDA, Refunding RB, Old Dominion Electric Co-op Project, AMT (AMBAC), 5.63%, 6/01/28		9,000		9,299,970
				10,724,477
Washington — 0.6%
County of King Washington, Refunding RB (AGM), 5.00%, 1/01/36		1,960		2,009,784
Wisconsin — 1.3%
Wisconsin Health & Educational Facilities Authority, RB, Aurora Health Care, 6.40%, 4/15/33		3,930		4,006,517
Wyoming — 1.6%
County of Sweetwater Wyoming, Refunding RB, Idaho Power Co. Project, 5.25%, 7/15/26		3,355		3,489,871
Wyoming Municipal Power Agency, RB, Series A:
5.50%, 1/01/33		800		836,736
5.50%, 1/01/38		750		778,477
				5,105,084
Total Municipal Bonds — 132.4%				418,830,571
Municipal Bonds Transferred to Tender Option Bond Trusts (i)
Alabama — 0.8%
Alabama Special Care Facilities Financing Authority, Birmingham, RB, Ascension Health Senior Credit, Series C-2, 5.00%, 11/15/36		2,519		2,530,220
California — 2.4%
California Educational Facilities Authority, RB, University of Southern California, Series A, 5.25%, 10/01/18		2,850		3,028,011
Los Angeles Community College District, California, GO, Election of 2001, Series A (AGM), 5.00%, 8/01/32		2,530		2,551,783
San Diego Community College District California, GO, Election of 2002, 5.25%, 8/01/33		1,840		1,896,238
				7,476,032
Colorado — 2.2%
Colorado Health Facilities Authority, RB, Catholic Health (AGM):
Series C-7, 5.00%, 9/01/36		2,710		2,694,228
Series C-3, 5.10%, 10/01/41		4,230		4,216,591
				6,910,819
Connecticut — 3.4%
Connecticut State Health & Educational Facility Authority, RB:
Yale University, Series T-1, 4.70%, 7/01/29		5,170		5,476,477
Yale University, Series X-3, 4.85%, 7/01/37		5,130		5,358,439
				10,834,916
Georgia — 1.5%
Private Colleges & Universities Authority, Refunding RB, Emory University, Series C, 5.00%, 9/01/38		4,638		4,837,690
Massachusetts — 1.0%
Massachusetts Water Resources Authority, RB, General, Series A, 5.00%, 8/01/41		3,150		3,208,811
New Hampshire — 0.7%
New Hampshire Health & Education Facilities Authority, Refunding RB, Dartmouth College, 5.25%, 6/01/39		2,219		2,392,583

See Notes to Financial Statements.
28	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (concluded)	BlackRock Municipal Income Trust II (BLE)
	(Percentages shown are based on Net Assets)

Municipal Bonds Transferred to Tender Option Bond Trusts (i)		Par (000)	Value
New York — 1.5%
New York City Municipal Water Finance Authority, RB, Series FF-2, 5.50%, 6/15/40	$	1,710	$	1,877,756
New York State Environmental Facilities Corporation New York, RB, Revolving Funds, New York City Municipal Water Project, Series B, 5.00%, 6/15/31		2,850		2,908,795
				4,786,551
Virginia — 3.2%
University of Virginia, Refunding RB, General, 5.00%, 6/01/40		5,910		6,219,979
Virginia HDA, RB, Sub-Series H-1 (NPFGC), 5.35%, 7/01/31		3,750		3,788,550
				10,008,529
Washington — 3.7%
Central Puget Sound Regional Transportation Authority, RB, Series A (AGM), 5.00%, 11/01/32		3,029		3,164,679
State of Washington, GO, Various, Purpose, Series E, 5.00%, 2/01/34		8,113		8,475,631
				11,640,310
Total Municipal Bonds Transferred to Tender Option Bond Trusts — 20.4%				64,626,461
Total Long-Term Investments (Cost — $487,168,898) — 152.8%				483,457,032
Short-Term Securities		Shares
FFI Institutional Tax-Exempt Fund, 0.16% (j)(k)		17,781,695		17,781,695
Total Short-Term Securities (Cost — $17,781,695) — 5.6%				17,781,695
Total Investments (Cost — $504,950,593*) — 158.4%				501,238,727
Other Assets Less Liabilities — 0.7%				2,133,089
Liability for Trust Certificates, Including Interest Expense and Fees Payable — (11.3)%				(35,582,354	)
Preferred Shares, at Redemption Value — (47.8)%				(151,306,561	)
Net Assets Applicable to Common Shares — 100.0%			$	316,482,901

* The cost and unrealized appreciation (depreciation) of investments as of February 28, 2010, as computed for federal income tax purposes, were as follows:

Aggregate cost	$	468,567,362
Gross unrealized appreciation	$	15,118,700
Gross unrealized depreciation		(18,010,524	)
Net unrealized depreciation	$	(2,891,824	)

(a)	Represents a zero-coupon bond. Rate shown reflects the current yield as of report date.
(b)	Issuer filed for bankruptcy and/or is in default of interest payments.
(c)	Non-income producing security.
(d)	Represents a step-up bond that pays an initial coupon rate for the first period and then a higher coupon rate for the following periods. Rate shown reflects the current yield as of report date.
(e)	When-issued security. Unsettled when-issued transactions were as follows:

Counterparty	Value		Unrealized Appreciation
Merrill Lynch & Co., Inc.	$	1,101,188	$	32,222

(f)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration to qualified institutional investors.
(g)	Security represents a beneficial interest in a trust. The collateral deposited into the trust is federally tax-exempt revenue bonds issued by various state or local governments, or their respective agencies or authorities. The security is subject to remarketing prior to its stated maturity, and is subject to mandatory redemption at maturity.
(h)	US 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.
(i)	Securities represent bonds transferred to a tender option bond trust in exchange for which the Trust 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.
(j)	Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:

Affiliate	Net Activity		Income
FFI Institutional Tax-Exempt Fund	$	3,976,628	$	6,053

(k)	Represents the current yield as of report date.
•	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 assets and liabilities
	•	Level 2 — other observable inputs (including, but not limited to: quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)
	•	Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Trust’s own assumptions used in determining the fair value of investments)
	The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in those securities. For information about the Trust’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 February 28, 2010 in determining the fair valuation of the Trust’s investments:

Valuation Inputs	Level 1		Level 2		Level 3		Total
Assets:
Long-Term Investments1		—	$	483,457,032		—	$	483,457,032
Short Term Securities	$	17,781,695		—		—		17,781,695
Total	$	17,781,695	$	483,457,032		—	$	501,238,727

¹ See above Schedule of Investments for values in each state or political subdivision.

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	29

Schedule of Investments February 28, 2010 (Unaudited)	BlackRock MuniHoldings Insured Investment Fund (MFL)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Alabama — 3.3%
Birmingham Special Care Facilities Financing Authority, RB, Children’s Hospital (AGC):
6.13%, 6/01/34	$	4,980	$	5,375,561
6.00%, 6/01/39		10,995		11,848,652
				17,224,213
Arizona — 2.7%
State of Arizona, COP, Department of Administration, Series A (AGM):
5.25%, 10/01/24		10,260		10,977,789
5.25%, 10/01/28		2,240		2,328,928
5.00%, 10/01/29		585		593,436
				13,900,153
California — 10.5%
California State Public Works Board, RB, Various Capital Projects, Series G-1 (AGC), 5.25%, 10/01/24		5,000		5,025,950
County of Sacramento California, RB, Senior Series A (AGC), 5.50%, 7/01/41		6,600		6,886,572
Los Angeles Community College District California, GO, Election of 2001, Series A (NPFGC), 5.00%, 8/01/32		10,000		10,073,700
Los Angeles Municipal Improvement Corp., Refunding RB, Real Property, Series B (AGC), 5.50%, 4/01/39		2,930		3,051,097
Los Angeles Unified School District California, GO, Series D, 5.25%, 7/01/25		3,485		3,768,087
Manteca Financing Authority California, RB, Manteca Sewer (AGC):
5.63%, 12/01/33		2,450		2,607,853
5.75%, 12/01/36		3,285		3,499,346
San Diego Public Facilities Financing Authority, Refunding RB, Series B (AGC), 5.38%, 8/01/34		4,690		4,914,182
State of California, GO, Various Purpose (AGC), 5.50%, 11/01/39		15,000		15,441,150
				55,267,937
Colorado — 1.3%
Colorado Health Facilities Authority, RB, Hospital, NCMC Inc. Project, Series B (AGM), 6.00%, 5/15/26		5,925		6,589,193
District of Columbia — 0.4%
District of Columbia, Refunding RB, Georgetown University, Series D (BHAC), 5.50%, 4/01/36		1,730		1,830,634
Florida — 53.8%
Alachua County School Board, RB (AMBAC), 5.25%, 7/01/29		3,075		3,149,108
Broward County Educational Facilities Authority, RB, Educational Facilities, Nova Southeastern University (AGC), 5.00%, 4/01/31		7,900		7,961,541
City of Cape Coral Florida, RB (NPFGC), 5.00%, 10/01/30		1,220		1,237,043
City of Jacksonville Florida, Refunding RB (NPFGC), 5.25%, 10/01/32		7,305		7,396,459
City of Leesburg Florida, RB (NPFGC):
5.25%, 10/01/27		1,605		1,641,048
5.25%, 10/01/34		3,425		3,433,117
City of Miami Beach Florida, RB:
(NPFGC), 5.25%, 9/01/25		4,400		4,524,080
(NPFGC), 5.38%, 9/01/30		1,910		1,927,228
Water and Sewer (AMBAC), 5.75%, 9/01/25		10,600		10,850,796
City of Orlando Florida, RB, Senior, 6th Cent Contract Payments, Series A (AGC), 5.25%, 11/01/38		2,650		2,693,328
City of Port St. Lucie Florida, RB (NPFGC):
5.25%, 9/01/26		1,280		1,302,605
5.25%, 9/01/27		1,345		1,369,291

Municipal Bonds	Par (000)		Value
Florida (continued)
City of Sunrise Florida, Refunding RB (AMBAC), 5.20%, 10/01/22	$	2,250	$	2,439,923
City of Tallahassee Florida, RB, Florida State University Project, Series A (NPFGC), 5.25%, 8/01/23		2,800		2,870,812
County of Lee Florida, RB, Series A, AMT (AGM), 6.00%, 10/01/29		19,925		20,177,250
County of Miami-Dade Florida, GO, Parks Program (NPFGC), 6.00%, 11/01/24		6,705		6,794,445
County of Miami-Dade Florida, RB:
(NPFGC), 5.25%, 10/01/30		365		374,402
Miami International Airport, Series A, AMT (AGM), 5.50%, 10/01/41		11,400		11,469,198
Miami International Airport, Series A, AMT (NPFGC), 6.00%, 10/01/29		8,000		8,112,400
Series A, AMT (AGM), 5.00%, 10/01/33		10,010		9,581,772
Series A, AMT (AGM), 5.13%, 10/01/35		11,105		10,743,199
County of Nassau Florida, RB (NPFGC), 5.13%, 9/01/33		2,675		2,687,332
County of Osceola Florida, RB:
(AMBAC), 5.38%, 10/01/18		3,155		3,417,433
Series A (NPFGC), 5.50%, 10/01/27		5,560		5,690,493
County of St. John’s Florida, RB (AGM):
5.00%, 10/01/31		3,200		3,279,072
5.00%, 10/01/35		1,095		1,106,125
5.00%, 10/01/37		6,055		6,150,306
Transportation Improvement (AMBAC), 5.13%, 10/01/32		2,750		2,785,420
County of Taylor Florida, RB (FGIC), 6.00%, 10/01/25 (a)		3,835		3,968,650
Emerald Coast Utilities Authority, RB, System (NPFGC):
5.25%, 1/01/26		1,130		1,178,387
5.25%, 1/01/36		1,245		1,253,628
Escambia County Housing Finance Authority, Refunding RB, Multi-County Program, Series A, AMT (NPFGC):
6.30%, 10/01/20		80		81,686
6.38%, 10/01/26		305		311,567
Florida Housing Finance Corp., HRB, Waverly Apartments, Series C-1, AMT (AGM), 6.30%, 7/01/30		2,055		2,103,888
Florida Housing Finance Corp., RB, Homeowner Mortgage, Series 11, AMT (AGM), 5.95%, 1/01/32		5,785		5,788,529
Florida Housing Finance Corp., Homeowner Mortgage, Refunding RB, AMT:
Series 2 (NPFGC), 5.75%, 7/01/14		755		756,291
Series 2 (NPFGC), 5.90%, 7/01/29		7,525		7,612,967
Series 4 (AGM), 6.25%, 7/01/22		560		584,914
Florida Municipal Loan Council, RB, Series B (NPFGC), 5.38%, 11/01/25		1,285		1,306,562
Hernando County School District, COP (NPFGC), 5.00%, 7/01/30		1,765		1,749,309
Hillsborough County Aviation Authority Florida, Refunding RB, Series C, AMT (AGC), 5.75%, 10/01/26		2,875		3,030,193
Jacksonville Port Authority, RB, AMT (AGC), 6.00%, 11/01/38		6,740		6,901,490
Lee County Housing Finance Authority, RB, Multi-County Program, Series A-1, AMT (GNMA), 7.20%, 3/01/33		50		50,808
Manatee County Housing Finance Authority, Refunding RB, S/F, Sub-Series 1, AMT (GNMA), 6.25%, 11/01/28		265		270,504
Miami-Dade County Expressway Authority Florida, RB, Series B (NPFGC), 5.25%, 7/01/27		8,995		9,254,596
Miami-Dade County Expressway Authority Florida, Refunding RB (NPFGC), 5.13%, 7/01/25		12,250		12,469,887

See Notes to Financial Statements.
30	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (continued)	BlackRock MuniHoldings Insured Investment Fund (MFL)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Florida (concluded)
Miami-Dade County Housing Finance Authority Florida, MRB, Marbrisa Apartments Project, Series 2A, AMT (AGM), 6.00%, 8/01/26	$	2,185	$	2,238,292
Miami-Dade County IDA, RB (AMBAC):
Airis Miami II LLC Project, AMT, 6.00%, 10/15/19		4,155		4,136,635
BAC Funding Corp. Project, Series A, 5.25%, 10/01/20		3,280		3,420,876
Orange County School Board, COP (AMBAC), 5.50%, 8/01/25		1,300		1,324,947
Orlando & Orange County Expressway Authority, RB, Series B (AMBAC):
5.00%, 7/01/30		425		430,457
5.00%, 7/01/35		5,445		5,446,307
Palm Beach County School District, COP, Refunding, Series B (AMBAC), 5.38%, 8/01/17		6,115		6,470,587
Polk County School Board, COP, Master Lease, Series A (AGM), 5.50%, 1/01/25		9,885		10,166,821
St. Lucie County School Board, COP (AGM):
Series A, 5.50%, 7/01/18		1,495		1,586,688
Series C, 5.50%, 7/01/18		1,170		1,241,756
St. Lucie West Services District, RB (NPFGC):
5.25%, 10/01/34		1,720		1,739,006
5.00%, 10/01/38		4,750		4,643,743
St. Lucie West Services District, Refunding RB, Senior Lien (NPFGC), 6.00%, 10/01/22		3,250		3,391,343
Tampa Bay Water Utility System Florida, RB (FGIC), 6.00%, 10/01/24 (a)		15,335		16,672,365
Village Center Community Development District, RB (NPFGC):
5.25%, 10/01/23		2,265		2,275,238
Series A, 5.38%, 11/01/34		10,775		9,223,184
Series A, 5.13%, 11/01/36		1,750		1,424,150
Volusia County IDA, RB, Student Housing, Stetson University Project, Series A (CIFG):
5.00%, 6/01/25		1,050		959,627
5.00%, 6/01/35		1,740		1,467,272
				282,098,376
Georgia — 7.3%
Augusta-Richmond County Georgia, RB (AGM), 5.25%, 10/01/39		4,350		4,505,861
City of Atlanta Georgia, RB, General, Subordinate Lien, Series C (AGM), 5.00%, 1/01/33		14,700		14,761,740
County of Fulton Georgia, RB (NPFGC), 5.25%, 1/01/35		3,000		3,069,990
Gwinnett County Hospital Authority, Refunding RB, Gwinnett Hospital System, Series D (AGM), 5.50%, 7/01/41		6,445		6,500,749
Metropolitan Atlanta Rapid Transit Authority, RB, Third Indenture, Series B (AGM), 5.00%, 7/01/34		9,240		9,584,282
				38,422,622
Illinois — 7.0%
Chicago Board of Education Illinois, GO, Refunding, Chicago School Reform Board, Series A (NPFGC), 5.50%, 12/01/26		3,745		4,205,860
Chicago Transit Authority, RB, Federal Transit Administration Section 5309, Series A (AGC), 6.00%, 6/01/26		6,315		7,230,485
City of Chicago Illinois, GO, Refunding, Projects, Series A (AGM):
5.00%, 1/01/28		4,415		4,653,498
5.00%, 1/01/29		6,845		7,147,686
5.00%, 1/01/30		2,730		2,828,662

Municipal Bonds	Par (000)		Value
Illinois (concluded)
City of Chicago Illinois, Refunding RB, Second Lien (NPFGC), 5.50%, 1/01/30	$	4,075	$	4,492,484
State of Illinois, RB, Build Illinois, Series B, 5.25%, 6/15/26		5,625		6,021,900
				36,580,575
Indiana — 2.5%
Indianapolis Local Public Improvement Bond Bank, Refunding RB, Waterworks Project, Series A (AGC), 5.50%, 1/01/38		12,140		13,072,352
Iowa — 1.1%
Iowa Finance Authority, Refunding RB, Iowa Health System (AGC), 5.25%, 2/15/29		5,500		5,654,330
Kentucky — 1.6%
Kentucky Municipal Power Agency, RB, Prairie State Project, Series A (BHAC), 5.25%, 9/01/42		4,070		4,207,688
Kentucky State Property & Buildings Commission, Refunding RB, Project No. 93 (AGC), 5.25%, 2/01/28		4,000		4,328,560
				8,536,248
Louisiana — 1.4%
Louisiana State Citizens Property Insurance Corp., RB, Series C-3 (AGC), 6.13%, 6/01/25		5,475		6,187,352
New Orleans Aviation Board Louisiana, Refunding RB (AGC), Restructuring GARB:
Series A-1, 6.00%, 1/01/23		500		570,665
Series A-2, 6.00%, 1/01/23		720		821,758
				7,579,775
Maryland — 0.8%
Maryland Health & Higher Educational Facilities Authority, Refunding RB, University of Maryland Medical System:
5.00%, 7/01/34		2,225		2,212,451
5.13%, 7/01/39		2,225		2,203,173
				4,415,624
Michigan — 15.2%
City of Detroit Michigan, RB:
Second Lien, Series B (AGM), 6.25%, 7/01/36		6,320		6,869,208
Second Lien, Series B (AGM), 7.00%, 7/01/36		850		974,262
Second Lien, Series B (NPFGC), 5.50%, 7/01/29		7,490		7,530,521
Senior Lien, Series B (AGM), 7.50%, 7/01/33		5,100		6,114,135
System, Second Lien, Series A (BHAC), 5.50%, 7/01/36		20,540		21,289,094
City of Detroit Michigan, Refunding RB:
Second Lien, Series E (BHAC), 5.75%, 7/01/31		6,000		6,417,600
Senior Lien, Series C-1 (AGM), 7.00%, 7/01/27		9,055		10,588,917
Michigan State Building Authority, RB, Facilities Program, Series H (AGM), 5.00%, 10/15/26		1,760		1,803,190
Michigan State Building Authority, Refunding RB, Facilities Program, Series I (AGC):
5.25%, 10/15/22		6,150		6,745,996
5.25%, 10/15/24		2,755		2,964,959
5.25%, 10/15/25		1,435		1,532,436
Royal Oak Hospital Finance Authority Michigan, Refunding RB, William Beaumont Hospital, 8.25%, 9/01/39		5,780		6,801,673
				79,631,991

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	31

Schedule of Investments (continued)	BlackRock MuniHoldings Insured Investment Fund (MFL)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Minnesota — 2.1%
City of Minneapolis Minnesota, Refunding RB, Fairview Health Services, Series B (AGC), 6.50%, 11/15/38	$	9,900	$	11,034,441
Nevada — 3.1%
County of Clark Nevada, RB, Las Vegas-McCarran International Airport, Series A (AGC), 5.25%, 7/01/39		16,005		16,052,695
New Jersey — 2.2%
New Jersey EDA, RB, School Facilities Construction, Series Z (AGC), 6.00%, 12/15/34		4,350		4,901,493
New Jersey Health Care Facilities Financing Authority, RB, Virtua Health (AGC), 5.50%, 7/01/38		6,500		6,814,080
				11,715,573
New York — 4.7%
New York City Transitional Finance Authority, Fiscal 2009, RB:
Series S-3, 5.25%, 1/15/39		5,625		5,888,925
Series S-4 (AGC), 5.50%, 1/15/29		4,000		4,422,760
New York State Dormitory Authority, ERB, Series B, 5.25%, 3/15/38		13,500		14,328,225
				24,639,910
Oregon — 0.4%
Medford Hospital Facilities Authority, RB, Asante Health System, Series A (AGC), 5.00%, 8/15/40		2,290		2,268,016
Puerto Rico — 1.4%
Puerto Rico Sales Tax Financing Corp., RB, First Sub-Series A, 6.38%, 8/01/39		6,610		7,081,095
South Carolina — 0.3%
City of Spartanburg South Carolina, RB, System (AGC), 5.00%, 6/01/39		1,700		1,746,835
Texas — 12.3%
City of Dallas Texas, Refunding RB (AGC), 5.25%, 8/15/38		4,000		4,083,720
City of Houston Texas, Refunding RB, Combined, First Lien, Series A (AGC):
6.00%, 11/15/35		12,700		14,400,530
6.00%, 11/15/36		9,435		10,675,231
5.38%, 11/15/38		5,000		5,315,200
County of Bexar Texas, RB, Venue Project, Motor Vehicle Rental (BHAC), 5.00%, 8/15/39		4,120		4,205,490
Harris County Health Facilities Development Corp., Refunding RB, Memorial Hermann Healthcare System, Series B, 7.25%, 12/01/35		1,500		1,683,750
Lower Colorado River Authority, Refunding RB, LCRA Transmission Services Project (AGC), 5.50%, 5/15/36		5,325		5,567,341
Lubbock Cooper ISD Texas, GO, School Building (AGC), 5.75%, 2/15/42		2,300		2,452,513
North Texas Tollway Authority, RB, System, First Tier, Series K-1 (AGC), 5.75%, 1/01/38		6,400		6,924,736
North Texas Tollway Authority, Refunding RB, System, First Tier, Series A (AGC), 5.75%, 1/01/40		7,000		7,500,990
Tarrant County Cultural Education Facilities Finance Corp., Refunding RB, Christus Health, Series A (AGC), 6.50%, 7/01/37		1,770		1,951,159
				64,760,660

Municipal Bonds	Par (000)		Value
Utah — 1.5%
City of Riverton Utah, RB, IHC Health Services Inc., 5.00%, 8/15/41	$	7,795	$	7,829,922
Virginia — 0.9%
Virginia Public School Authority, RB, School Financing, 6.50%, 12/01/35		4,300		4,940,313
Total Municipal Bonds — 137.8%				722,873,483

Municipal Bonds Transferred to Tender Option Bond Trusts (b)
California — 0.5%
Los Angeles Unified School District California, GO, Series I, 5.00%, 1/01/34	2,400	2,406,960
District of Columbia — 0.7%
District of Columbia Water & Sewer Authority, RB, Series A, 6.00%, 10/01/35	3,381	3,784,564
Florida — 7.2%
City of Jacksonville Florida, RB, Better Jacksonville (NPFGC), 5.00%, 10/01/27	10,000	10,254,000
Hillsborough County Aviation Authority, RB, Series A, AMT (AGC), 5.50%, 10/01/38	10,657	10,809,357
Jacksonville Electric Authority Florida, RB, Issue Three, Series Two, River Power Pike, 5.00%, 10/01/37	6,080	6,117,879
Lee County Housing Finance Authority, RB, Multi-County Program, Series A-2, AMT (GNMA), 6.00%, 9/01/40	5,595	6,088,983
Manatee County Housing Finance Authority, RB, Series A, AMT (GNMA), 5.90%, 9/01/40	4,253	4,452,493
		37,722,712
Indiana — 1.9%
Indiana Health & Educational Facilities Financing Authority, Refunding RB, Saint Francis, Series E (AGM), 5.25%, 5/15/41	9,850	10,006,319
Kentucky — 0.1%
Kentucky State Property & Buildings Commission, Refunding RB, Project No. 93 (AGC), 5.25%, 2/01/27	404	437,568
Nevada — 2.7%
Clark County Water Reclamation District, GO:
Limited Tax, 6.00%, 7/01/38	8,000	8,891,520
Series B, 5.50%, 7/01/29	5,008	5,487,074
		14,378,594
New Jersey — 1.5%
New Jersey State Housing & Mortgage Finance Agency, RB, S/F Housing, Series CC, 5.25%, 10/01/29	7,532	7,762,383
New York — 1.1%
New York City Municipal Water Finance Authority, RB, Series FF-2, 5.50%, 6/15/40	4,994	5,485,023
Texas — 2.5%
City of San Antonio Texas, Refunding RB, Series A, 5.25%, 2/01/31	12,027	13,052,824
Total Municipal Bonds Transferred to Tender Option Bond Trusts — 18.2%		95,036,947
Total Long-Term Investments (Cost — $793,874,309)– 156.0%		817,910,430

See Notes to Financial Statements.
32	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (concluded)	BlackRock MuniHoldings Insured Investment Fund (MFL)
	(Percentages shown are based on Net Assets)

Short-Term Securities	Shares		Value
FFI Institutional Tax-Exempt Fund, 0.16% (c)(d)		21,461,708	$	21,461,708
Total Short-Term Securities (Cost — $21,461,708) — 4.1%				21,461,708
Total Investments (Cost — $815,336,017*) �� 160.1%				839,372,138
Other Assets Less Liabilities — 1.8%				9,536,503
Liabilities for Trust Certificates, Including Interest Expense and Fees Payable — (9.5)%				(49,804,927	)
Preferred Shares, at Redemption Value — (52.4)%				(274,663,552	)
Net Assets Applicable to Common Shares — 100.0%			$	524,440,162

* The cost and unrealized appreciation (depreciation) of investments as of February 28, 2010, as computed for federal income tax purposes, were as follows:

Aggregate cost	$	765,600,427
Gross unrealized appreciation	$	28,271,289
Gross unrealized depreciation		(4,260,112	)
Net unrealized appreciation	$	24,011,177

(a)	US 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)	Securities represent bonds transferred to a tender option bond trust in exchange for which the Trust 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.
(c)	Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:

Affiliate	Net Activity			Income
FFI Institutional Tax-Exempt Fund	$	(5,544,071	)	$	14,542

(d)	Represents the current yield as of report date.
•	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 assets and liabilities
	•	Level 2 — other observable inputs (including, but not limited to: quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)
	•	Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Trust’s own assumptions used in determining the fair value of investments)
	The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in those securities. For information about the Trust’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 February 28, 2010 in determining the fair valuation of the Trust’s investments:

	Investment in Securities
Valuation Inputs	Level 1		Level 2		Level 3		Total
Assets:
Long-Term Investments1		—	$	817,910,430		—	$	817,910,430
Short-Term Securities	$	21,461,708		—		—		21,461,708
Total	$	21,461,708	$	817,910,430		—	$	839,372,138

¹ See above Schedule of Investments for values in each state or political subdivision.

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	33

Schedule of Investments February 28, 2010 (Unaudited)	BlackRock MuniVest Fund, Inc. (MVF)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Alabama — 2.3%
Camden IDB Alabama, RB, Weyerhaeuser Co. Project, Series A, 6.13%, 12/01/13 (a)	$	2,550	$	3,014,177
Prattville IDB Alabama, RB, International Paper Co. Project, Series A, AMT, 4.75%, 12/01/30		6,500		5,181,670
Selma IDB Alabama, Refunding RB, International Paper Co. Project, Series B, 5.50%, 5/01/20		5,000		5,010,650
				13,206,497
Arizona — 1.7%
Maricopa County IDA Arizona, RB, Arizona Charter Schools Project, Series A, 6.75%, 7/01/29		4,100		2,811,985
Pima County IDA, RB, Arizona Charter Schools Project, Series E, 7.25%, 7/01/31		2,025		1,941,165
Pima County IDA, Refunding RB:
Arizona Charter Schools Project, Series I, 6.10%, 7/01/24 (b)		490		433,028
Arizona Charter Schools Project, Series I, 6.30%, 7/01/31 (b)		985		842,027
Arizona Charter Schools Project, Series O, 5.00%, 7/01/26		1,545		1,189,233
Charter Schools II, Series A, 6.75%, 7/01/21		925		885,743
State of Arizona, COP, Department of Administration, Series A (AGM), 5.25%, 10/01/28		1,850		1,923,445
				10,026,626
California — 15.6%
California HFA, RB, Home Mortgage, Series K, AMT, 5.50%, 2/01/42		4,115		4,370,048
California Health Facilities Financing Authority, RB, Cedars-Sinai Medical Center, 5.00%, 8/15/39		1,470		1,375,523
California Health Facilities Financing Authority, Refunding RB, Series A:
Catholic Healthcare West, 6.00%, 7/01/34		1,055		1,107,212
St. Joseph Health System, 5.75%, 7/01/39		5,000		5,160,050
California State Public Works Board, RB:
Department of Corrections, Series C, 5.50%, 6/01/22		5,000		5,062,150
Department of Corrections, Series C, 5.50%, 6/01/23		6,000		6,064,380
Department of Mental Health, Coalinga, Series A, 5.13%, 6/01/29		11,075		10,201,515
California Statewide Communities Development Authority, RB, Health Facility, Memorial Health Services, Series A, 6.00%, 10/01/23		5,240		5,452,325
City of Chula Vista California, RB, San Diego Gas & Electric, Series B, AMT, 5.00%, 12/01/27		1,250		1,195,987
Golden State Tobacco Securitization Corp. California, RB, ARS, Asset-Backed (a):
Series A-3, 7.88%, 6/01/13		10,725		12,972,853
Series A-4, 7.80%, 6/01/13		3,750		4,527,412
Series A-5, 7.88%, 6/01/13		1,425		1,723,666
Los Angeles Department of Airports, RB, Series A, 5.25%, 5/15/39		1,200		1,213,896
State of California, GO, Various Purpose, 6.50%, 4/01/33		9,700		10,472,799
University of California, RB, Series O, 5.25%, 5/15/39		20,000		21,151,200
				92,051,016

Municipal Bonds	Par (000)		Value
Colorado — 1.0%
Colorado Health Facilities Authority, RB, Catholic Health Initiatives, Series D, 6.25%, 10/01/33	$	2,500	$	2,767,600
Colorado Health Facilities Authority, Refunding RB, Evangelical Lutheran, Series A, 5.25%, 6/01/34		3,000		2,714,040
Colorado Housing & Finance Authority, Refunding RB, S/F Program, Senior Series A-2, AMT:
6.60%, 5/01/28		375		385,838
7.50%, 4/01/31		160		171,006
				6,038,484
Connecticut — 0.4%
Mohegan Tribe of Indians of Connecticut, RB, Public Improvement, Priority Distribution, 6.25%, 1/01/31		2,810		2,263,202
District of Columbia — 0.2%
Metropolitan Washington Airports Authority, RB, First Senior Lien, Series A:
5.00%, 10/01/39		415		421,623
5.25%, 10/01/44		650		669,734
				1,091,357
Florida — 9.2%
County of Miami-Dade, Florida, GO, Building Better Communities Program:
Series B, 6.38%, 7/01/28		4,630		5,302,739
Series B-1, 5.63%, 7/01/38		5,000		5,270,050
County of Miami-Dade, Florida, RB, Miami Dade County Water & Sewer System (AGM), 5.00%, 10/01/39 (c)		14,750		14,704,128
County of Miami-Dade, Florida, Refunding RB, Miami International Airport:
AMT (AGC), 5.00%, 10/01/40		10,000		9,389,600
Series A-1, 5.38%, 10/01/41		10,290		10,334,864
Hillsborough County IDA, RB, H. Lee Moffitt Cancer Center Project, Series A, 5.25%, 7/01/37		6,500		6,020,560
Miami-Dade County IDA, RB, Waste Management Inc. Project, Series 1, AMT, 7.00%, 12/01/18		3,200		3,273,184
				54,295,125
Georgia — 2.5%
De Kalb Private Hospital Authority, Refunding RB, Children’s Healthcare, 5.25%, 11/15/39		3,335		3,367,616
Gainesville Redevelopment Authority, Refunding RB, Riverside Military Academy, 5.13%, 3/01/37		1,100		680,086
Monroe County Development Authority Georgia, Refunding RB, Oglethorpe Power Corp. Scherer, Series A, 6.80%, 1/01/11		4,785		4,987,932
Municipal Electric Authority of Georgia, RB, Series W:
6.60%, 1/01/18		4,565		5,399,162
6.60%, 1/01/18 (d)		250		288,253
				14,723,049
Idaho — 0.0%
Idaho Housing & Finance Association, Refunding RB, S/F Mortgage, Senior Series E-2, AMT, 6.90%, 1/01/27		135		135,232
Illinois — 10.2%
City of Chicago, Illinois, ARB, General, 3rd Lien, Series B-2, AMT (NPFGC), 6.00%, 1/01/27		17,080		17,718,109
City of Chicago, Illinois, RB, Series C, AMT (GNMA), 7.00%, 3/01/32		60		61,728
Illinois Finance Authority, RB:
Advocate Health Care Network, Series D, 6.50%, 11/01/38		9,700		10,785,818
Community Rehabilitation Providers Facilities, Series A, 6.50%, 7/01/22		2,140		2,146,163

See Notes to Financial Statements.
34	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (continued)	BlackRock MuniVest Fund, Inc. (MVF)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Illinois (concluded)
Illinois Finance Authority, Refunding RB, Northwestern Memorial Hospital, Series A, 6.00%, 8/15/39	$	9,000	$	9,900,270
Regional Transportation Authority, RB:
Series A (AMBAC), 7.20%, 11/01/20		3,500		4,327,365
Series C (NPFGC), 7.75%, 6/01/20		4,000		5,149,720
Village of Hodgkins Illinois, RB, MBM Project, AMT, 6.00%, 11/01/23		10,000		10,004,900
				60,094,073
Indiana — 5.5%
Indiana Health & Educational Facilities Financing Authority, RB, Clarian Health Obligation, Series A, 5.25%, 2/15/40		8,980		8,550,756
Indiana Transportation Finance Authority, RB, Series A, 6.80%, 12/01/16		8,195		9,483,008
Indianapolis Local Public Improvement Bond Bank, Refunding RB, Series D, 6.75%, 2/01/14		12,875		14,238,463
				32,272,227
Kansas — 0.4%
Sedgwick & Shawnee Counties Kansas, RB, Mortgage-Backed Securities Program, Series A-4, AMT (GNMA), 5.95%, 12/01/33		2,440		2,550,654
Kentucky — 2.6%
Kentucky Economic Development Finance Authority, Refunding RB, Owensboro Medical Health System, Series A, 6.38%, 6/01/40 (c)		2,205		2,197,393
Kentucky Housing Corporation, RB, Series L, AMT, 5.25%, 1/01/38		7,235		7,393,012
Louisville/Jefferson County Metropolitan Government, Refunding RB, Norton Healthcare Inc., 5.25%, 10/01/36		6,045		5,810,333
				15,400,738
Louisiana — 2.3%
Louisiana Public Facilities Authority, RB, Franciscan Missionaries, Series A:
5.00%, 8/15/33		8,720		7,914,359
5.25%, 8/15/36		6,090		5,670,582
				13,584,941
Maine — 1.2%
Maine Health & Higher Educational Facilities Authority, RB, Series A, 5.00%, 7/01/39		5,000		5,063,000
Portland New Public Housing Authority Maine, Refunding RB, Senior Living, Series A:
5.70%, 8/01/21		775		766,002
6.00%, 2/01/34		1,190		1,119,576
				6,948,578
Maryland — 1.6%
Maryland Community Development Administration, RB, AMT, 5.10%, 9/01/37		1,835		1,839,276
Maryland Community Development Administration, Refunding RB, Residential, Series D, AMT, 4.90%, 9/01/42		3,250		3,097,802
Maryland Health & Higher Educational Facilities Authority, Refunding RB, University of Maryland Medical System:
5.00%, 7/01/34		2,100		2,088,156
5.13%, 7/01/39		2,100		2,079,399
				9,104,633

Municipal Bonds	Par (000)		Value
Massachusetts — 7.3%
Boston Water & Sewer Commission, RB, 9.25%, 1/01/11 (d)	$	985	$	1,054,285
Massachusetts Bay Transportation Authority, Refunding RB, General Transportation System, Series A, 7.00%, 3/01/19		3,010		3,724,905
Massachusetts HFA, HRB, Series A, AMT, 5.20%, 12/01/37		3,000		3,005,130
Massachusetts HFA, RB, S/F, Series 130, AMT, 5.00%, 12/01/32		2,500		2,476,325
Massachusetts HFA, Refunding HRB, Series D, AMT, 4.85%, 6/01/40		3,000		2,793,930
Massachusetts School Building Authority, RB, Series A (AGM), 5.00%, 8/15/30		10,000		10,412,000
Massachusetts Water Resources Authority, RB, Series A, 6.50%, 7/15/19 (d)		16,000		19,637,920
				43,104,495
Michigan — 5.5%
City of Detroit Michigan, RB, Second Lien, Series B (AGM):
6.25%, 7/01/36		2,500		2,717,250
7.00%, 7/01/36		1,250		1,432,738
Michigan State Hospital Finance Authority, Refunding RB:
Henry Ford Health System, Series A, 5.25%, 11/15/46		7,950		7,053,955
Hospital, Crittenton, Series A, 5.63%, 3/01/27		1,900		1,880,506
Hospital, Oakwood Obligation Group, Series A, 5.00%, 7/15/25		1,900		1,790,636
Hospital, Sinai Hospital, 6.70%, 1/01/26		1,000		911,770
McLaren Health Care, 5.75%, 5/15/38		7,285		7,417,878
Trinity Health, Series A, 6.00%, 12/01/20		4,200		4,304,958
Royal Oak Hospital Finance Authority Michigan, Refunding RB, William Beaumont Hospital, 8.25%, 9/01/39		4,100		4,824,716
				32,334,407
Mississippi — 5.4%
County of Lowndes Mississippi, Refunding RB, Weyerhaeuser Co. Project:
Series A, 6.80%, 4/01/22		9,160		9,847,824
Series B, 6.70%, 4/01/22		4,500		4,799,835
Mississippi Business Finance Corp., Refunding RB, System Energy Resource Inc. Project:
5.88%, 4/01/22		15,000		14,951,550
5.90%, 5/01/22		2,250		2,245,523
				31,844,732
Nevada — 0.9%
County of Clark Nevada, RB, Series B, 5.75%, 7/01/42		5,000		5,205,550
New Hampshire — 0.4%
New Hampshire Health & Education Facilities Authority, Refunding RB, Elliot Hospital, Series B, 5.60%, 10/01/22		2,525		2,532,171
New Jersey — 6.1%
New Jersey EDA, RB, Cigarette Tax:
5.50%, 6/15/24		9,080		8,955,513
5.75%, 6/15/29		2,885		2,858,170
5.75%, 6/15/34		4,695		4,504,899
New Jersey EDA, Refunding RB, School Facilities Construction, Series AA, 5.25%, 12/15/33		10,000		10,455,900
New Jersey State Housing & Mortgage Finance Agency, RB, Series AA, 6.38%, 10/01/28		1,530		1,693,144
Tobacco Settlement Financing Corp. New Jersey, RB, 7.00%, 6/01/13 (a)		5,980		7,114,346
				35,581,972

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	35

Schedule of Investments (continued)	BlackRock MuniVest Fund, Inc. (MVF)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
New York — 3.6%
Metropolitan Transportation Authority, RB, Series 2008-C:
6.25%, 11/15/23	$	3,245	$	3,763,778
6.50%, 11/15/28		14,925		17,114,945
				20,878,723
North Carolina — 0.6%
City of Charlotte, North Carolina, Refunding RB, Series A, 5.50%, 7/01/34		800		845,192
Gaston County Industrial Facilities & Pollution Control Financing Authority North Carolina, RB, Exempt Facilities, National Gypsum Co. Project, AMT, 5.75%, 8/01/35		4,105		2,651,009
				3,496,201
Ohio — 5.4%
Buckeye Tobacco Settlement Financing Authority, RB, Asset-Backed, Senior Series A-2, 6.50%, 6/01/47		27,500		22,616,550
Ohio Air Quality Development Authority, RB, Ohio Valley Electric Corp., 5.63%, 10/01/19		930		970,948
Ohio Higher Educational Facility Commission, Refunding RB, Kenyon College Project, 5.25%, 7/01/44		8,000		8,224,640
				31,812,138
Pennsylvania — 1.0%
Lycoming County Authority, Refunding RB, Susquehanna Health System Project, Series A, 5.75%, 7/01/39		3,950		3,878,268
Philadelphia Authority for Industrial Development, RB:
Arbor House Inc. Project, Series E, 6.10%, 7/01/33		1,000		934,020
Rieder House Project, Series A, 6.10%, 7/01/33		1,355		1,265,597
				6,077,885
Puerto Rico — 2.8%
Puerto Rico Sales Tax Financing Corp., RB, First Sub-Series A, 6.38%, 8/01/39		13,000		13,926,510
Puerto Rico Sales Tax Financing Corp., Refunding RB, CAB, Series A (NPGFC), 5.71%, 8/01/41 (e)		15,000		2,253,300
				16,179,810
South Carolina — 1.0%
County of Georgetown, South Carolina, Refunding RB, International Paper Co. Project, Series A, AMT, 5.55%, 12/01/29		1,000		910,530
County of Richland, South Carolina, Refunding RB, International Paper Co. Project, AMT, 6.10%, 4/01/23		5,000		5,044,600
				5,955,130
South Dakota — 0.4%
South Dakota Health & Educational Facilities Authority, RB, Sanford Health, 5.00%, 11/01/40		2,605		2,525,365
Texas — 12.4%
Brazos River Authority, Refunding RB, Texas Utility Co., Series, AMT, 7.70%, 4/01/33		3,055		1,943,713
Brazos River Harbor Navigation District, Refunding RB, Dow Chemical Co. Project, Series A7, AMT, 6.63%, 5/15/33		11,460		11,641,068
City of Houston, Texas, RB, Senior Lien, Series A, 5.50%, 7/01/34		8,335		8,921,117
Guadalupe-Blanco River Authority, RB, EI du Pont de Nemours & Co. Project, AMT, 6.40%, 4/01/26		10,250		10,257,073
Gulf Coast Waste Disposal Authority, Refunding RB, Series A, AMT, 6.10%, 8/01/24		4,000		3,954,480

Municipal Bonds	Par (000)		Value
Texas (concluded)
Harris County Health Facilities Development Corp., Refunding RB, Memorial Hermann Healthcare System, B:
7.13%, 12/01/31	$	3,500	$	3,929,730
7.25%, 12/01/35		5,400		6,061,500
Harris County-Houston Sports Authority, Refunding RB, Senior Lien, Series G (NPFGC), 5.75%, 11/15/20		5,500		5,595,260
Houston Industrial Development Corp., RB, Senior, Air Cargo, AMT, 6.38%, 1/01/23		1,790		1,636,561
La Vernia Higher Education Finance Corp., RB, KIPP Inc., 6.25%, 8/15/39		925		947,533
Matagorda County Navigation District No. 1, Texas, Refunding RB, CenterPoint Energy Project, 5.60%, 3/01/27		9,355		9,193,907
North Texas Tollway Authority, Refunding RB, First Tier, Series A, 6.25%, 1/01/39		3,500		3,744,860
Texas Private Activity Bond Surface Transportation Corp., RB, Senior Lien, Note Mobility, 6.88%, 12/31/39		4,710		4,874,473
				72,701,275
U.S. Virgin Islands — 1.4%
United States Virgin Islands, Refunding RB, Senior Secured, Hovensa Coker Project, AMT, 6.50%, 7/01/21		8,000		8,100,400
Vermont — 0.2%
Vermont Educational & Health Buildings Financing Agency, RB, Developmental & Mental Health, Series A, 6.38%, 6/15/22		1,000		968,870
Virginia — 2.7%
Chesterfield County IDA, Refunding RB, Virginia Electric & Power Co., Series A, 5.88%, 6/01/17		1,425		1,477,326
City of Norfolk Virginia, Refunding RB, Series B (AMBAC), 5.50%, 2/01/31		4,225		4,122,290
Fairfax County EDA, Refunding RB, Goodwin House Inc.:
5.13%, 10/01/37		2,000		1,848,740
5.13%, 10/01/42		7,015		6,400,977
Virginia HDA, Refunding RB, Sub-Series A3, AMT, 5.05%, 7/01/26		1,325		1,348,506
Virginia Small Business Financing Authority, Refunding RB, Sentara Healthcare, 5.00%, 11/01/40		525		529,132
				15,726,971
Washington — 4.7%
Energy Northwest, Refunding RB, Series B, 7.13%, 7/01/16		14,320		18,165,063
Seattle Housing Authority Washington, HRB, Replacement Housing Projects, 6.13%, 12/01/32		2,265		2,069,440
Washington Health Care Facilities Authority, Refunding RB, Catholic Health Initiatives, Series D, 6.38%, 10/01/36		7,000		7,670,670
				27,905,173
West Virginia — 0.4%
West Virginia Hospital Finance Authority, Refunding RB, Charleston, Series A, 5.63%, 9/01/32		2,500		2,470,125

See Notes to Financial Statements.
36	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Schedule of Investments (continued)	BlackRock MuniVest Fund, Inc. (MVF)
	(Percentages shown are based on Net Assets)

Municipal Bonds	Par (000)		Value
Wisconsin — 2.4%
City of Milwaukee, Wisconsin, RB, Senior, Air Cargo, AMT, 6.50%, 1/01/25	$	1,605	$	1,471,641
Wisconsin Health & Educational Facilities Authority, MRB, Hudson Memorial Hospital (FHA), 5.70%, 1/15/29		4,500		4,570,785
Wisconsin Health & Educational Facilities Authority, RB, SynergyHealth Inc., 6.00%, 11/15/32		3,040		3,130,774
Wisconsin Housing & EDA, Refunding RB, Series A, AMT, 5.63%, 3/01/31		4,995		5,172,722
				14,345,922
Wyoming — 0.8%
County of Sweetwater, Wyoming, Refunding RB, Idaho Power Co. Project, 5.25%, 7/15/26		4,500		4,680,900
Total Municipal Bonds — 122.1%				718,214,647
Municipal Bonds Transferred to Tender Option Bond Trusts (f)
Arizona — 0.6%
Phoenix Civic Improvement Corp., RB, Junior Lien, Series A, 5.00%, 7/01/34		3,500		3,640,245
California — 1.8%
Los Angeles Community College District, California, GO, 2008 Election, Series A, 6.00%, 8/01/33		9,586		10,649,757
Connecticut — 2.1%
Connecticut State Health & Educational Facility Authority, RB, Yale University, Series Z-3, 5.05%, 7/01/42		12,000		12,630,720
District of Columbia — 1.4%
District of Columbia Water & Sewer Authority, RB, Series A, 5.50%, 10/01/39		7,495		8,024,145
Illinois — 3.4%
City of Chicago, Illinois, Refunding RB, Second Lien (AGM), 5.25%, 11/01/33		1,330		1,396,606
Illinois Finance Authority, RB, University of Chicago, Series B, 6.25%, 7/01/38		10,000		11,317,400
Illinois State Toll Highway Authority, RB, Series B, 5.50%, 1/01/33		6,999		7,495,085
				20,209,091
Kentucky — 4.3%
Kentucky Economic Development Finance Authority, Refunding RB, St. Elizabeth, Series A, 5.50%, 5/01/39		8,003		8,152,399
Lexington-Fayette Urban County Airport Board, Refunding RB, Series A, 5.00%, 7/01/27		7,001		7,452,970
Louisville & Jefferson County Metropolitan Government Parking Authority, RB, Series A, 5.38%, 12/01/39		9,195		9,508,366
				25,113,735
Maryland — 0.8%
Maryland State Transportation Authority, RB, Transportation Facilities Project (AGM), 5.00%, 7/01/41		4,710		4,938,906
Nevada — 3.0%
Clark County Water Reclamation District, GO, Series B, 5.75%, 7/01/34		15,789		17,382,692

Municipal Bonds Transferred to Tender Option Bond Trusts (f)	Par (000)		Value
New York — 5.0%
New York City Municipal Water Finance Authority, RB:
Series DD, 5.00%, 6/15/37	$	24,199	$	24,993,899
Series FF-2, 5.50%, 6/15/40		4,154		4,562,617
				29,556,516
North Carolina — 3.1%
North Carolina Capital Facilities Finance Agency, Refunding RB:
Duke University Project, Series A, 5.00%, 10/01/41		12,678		13,109,313
Wake Forest University, 5.00%, 1/01/38		5,000		5,247,500
				18,356,813
Ohio — 3.3%
County of Montgomery, Ohio, Refunding RB, Catholic Healthcare, Series A, 5.50%, 5/01/34		5,470		5,730,536
Ohio Higher Educational Facility Commission, Refunding RB, Hospital, Cleveland Clinic Health, Series A, 5.25%, 1/01/33		4,400		4,525,004
State of Ohio, RB, Cleveland Clinic Health, Series B, 5.50%, 1/01/34		8,500		8,924,235
				19,179,775
South Carolina — 0.6%
South Carolina State Housing Finance & Development Authority, Refunding RB, Series B-1, 5.55%, 7/01/39		3,269		3,360,589
Texas — 6.7%
Harris County Health Facilities Development Corp., Refunding RB, School Health Care System, Series B, 5.75%, 7/01/27		20,970		25,819,522
Texas Department of Housing & Community Affairs, MRB, Series B (GNMA), AMT, 5.25%, 9/01/32		7,509		7,587,598
Texas State University Systems, Texas, RB (AGM), 5.00%, 3/15/30		5,667		5,851,642
				39,258,762
Virginia — 0.4%
Fairfax County IDA, Virginia, Refunding RB, Health Care, Inova Health System, Series A, 5.50%, 5/15/35		2,099		2,192,507
Washington — 4.4%
Central Puget Sound Regional Transportation Authority, Washington, RB, Series A:
5.00%, 11/01/36		11,000		11,396,495
(AGM), 5.00%, 11/01/32		14,007		14,632,726
				26,029,221
Wisconsin — 1.0%
Wisconsin Health & Educational Facilities Authority, Refunding RB, Froedtert & Community Health Inc., 5.25%, 4/01/39		6,099		6,128,913
Total Municipal Bonds Transferred to Tender Option Bond Trusts — 41.9%				246,652,387
Total Long-Term Investments
(Cost — $937,085,076) — 164.0%				964,867,034

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	37

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

Short-Term Securities	Shares		Value
FFI Institutional Tax-Exempt Fund, 0.16% (g)(h)		1,398,855	$	1,398,855
Total Short-Term Securities (Cost — $1,398,855) — 0.2%				1,398,855
Total Investments (Cost — $938,483,931*) — 164.2%				966,265,889
Liabilities in Excess of Other Assets — (0.8)%				(4,749,897	)
Liability for Trust Certificates, Including Interest Expense and Fees Payable — (22.0)%				(129,255,144	)
Preferred Shares, at Redemption Value — (41.4)%				(243,848,135	)
Net Assets Applicable to Common Shares — 100.0%			$	588,412,713

* The cost and unrealized appreciation (depreciation) of investments as of February 28, 2010, as computed for federal income tax purposes, were as follows:

Aggregate cost	$	811,214,978
Gross unrealized appreciation	$	47,508,359
Gross unrealized depreciation		(21,641,147	)
Net unrealized appreciation	$	25,867,212

(a)	US 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)	Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration to qualified institutional investors.
(c)	When-issued security. Unsettled when-issued security transactions were as follows:

Counterparty	Market Value		Unrealized Appreciation
Apex Securities	$	49,845	$	76
JPMorgan Securities Ltd.	$	498,445	$	760
Jackson Securities	$	498,445	$	760
Loop Capital	$	99,689	$	152
Merrill Lynch & Co., Inc.	$	2,197,393	$	64,298
Raymond C. Forbes & Co., Inc.	$	13,557,704	$	20,672

(d)	Security is collateralized by Municipal or US Treasury obligations.
(e)	Represents a zero-coupon bond. Rate shown reflects the current yield as of report date.
(f)	Securities represent bonds transferred to a tender option bond trust in exchange for which the Trust 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.
(g)	Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2 (a)(3) of the Investment Company Act of 1940, were as follows:

Affiliate		Net Activity			Income
FFI Institutional Tax-Exempt Fund	$	(2,705,509	)	$	10,800

(h) Represents the current yield as of report date.

•	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 assets and liabilities
	•	Level 2 — other observable inputs (including, but not limited to: quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)
	•	Level 3 — unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Trust’s own assumptions used in determining the fair value of investments)
	The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in those securities. For information about the Trust’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 February 28, 2010 in determining the fair valuation of the Trust’s investments:

	Investments in Securities
Valuation Inputs	Level 1		Level 2		Level 3		Total
Assets:
Long-Term Investments1		—	$	964,867,034		—	$	964,867,034
Short-Term Securities	$	1,398,855		—		—		1,398,855
Total	$	1,398,855	$	964,867,034		—	$	966,265,889

¹ See above Schedule of Investments for values in each state or political subdivision.

See Notes to Financial Statements.
38	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Statements of Assets and Liabilities

February 28, 2010 (Unaudited)	BlackRock Insured Municipal Income Trust (BYM)			BlackRock Insured Municipal Income Investment Trust (BAF)			BlackRock Municipal Bond Trust (BBK)			BlackRock Municipal Bond Investment Trust (BIE)			BlackRock Municipal Income Trust II (BLE)			BlackRock MuniHoldings Insured Investment Fund (MFL)			BlackRock MuniVest Fund, Inc. (MVF)
Assets
Investments at value — unaffiliated1	$	561,461,686		$	186,403,010		$	226,900,121		$	76,978,827		$	483,457,032		$	817,910,430		$	964,867,034
Investments at value — affiliated2		6,590,771			6,303,277			4,158,073			956,848			17,781,695			21,461,708			1,398,855
Investments sold receivable		6,473,590			1,713,658			1,447,891			215,251			8,868,798			1,161,214			10,687,578
Interest receivable		4,938,089			2,277,943			2,869,382			845,842			5,976,771			11,311,873			12,624,159
Income receivable — affiliated		210			61			78			20			182			313			334
Prepaid expenses		47,557			16,297			23,390			9,606			31,659			46,674			51,850
Other assets		48,543			12,481			18,898			4,194			44,042			74,347			79,359
Total assets		579,560,446			196,726,727			235,417,833			79,010,588			516,160,179			851,966,559			989,709,169
Accrued Liabilities
Bank overdraft		—			1,044			—			629			—			6,455			252
Investments purchased payable		10,082,869			—			2,362,664			338,587			10,588,781			—			24,347,710
Income dividends payable — Common Shares		1,797,038			598,282			883,022			246,000			1,880,752			2,561,401			3,295,348
Investment advisory fees payable		215,956			74,813			88,607			29,959			192,182			328,222			370,801
Officer’s and Trustees’ fees payable		50,476			13,658			20,336			5,178			45,835			75,986			81,151
Interest expense and fees payable		37,575			22,791			3,936			5,927			19,165			44,392			71,445
Other affiliates payable		4,565			640			1,840			254			3,990			2,660			3,104
Other accrued expenses payable		119,081			64,677			76,035			49,730			76,823			83,195			94,811
Total accrued liabilities		12,307,560			775,905			3,436,440			676,264			12,807,528			3,102,311			28,264,622
Other Liabilities
Trust certificates3		63,475,997			28,697,356			5,899,148			11,821,747			35,563,189			49,760,534			129,183,699
Total Liabilities		75,783,557			29,473,261			9,335,588			12,498,011			48,370,717			52,862,845			157,448,321
Preferred Shares at Redemption Value
$25,000 per share liquidation preference, plus unpaid dividends4,5		137,257,176			42,277,543			79,902,974			17,850,626			151,306,561			274,663,552			243,848,135
Net Assets Applicable to Common Shareholders	$	366,519,713		$	124,975,923		$	146,179,271		$	48,661,951		$	316,482,901		$	524,440,162		$	588,412,713
Net Assets Applicable to Common Shareholders Consist of
Paid-in capital6,7,8	$	372,369,457		$	123,923,627		$	147,694,691		$	47,237,934		$	329,955,968		$	524,440,677		$	564,171,414
Undistributed net investment income		5,918,799			2,154,289			2,487,342			777,017			4,978,816			8,088,370			12,745,063
Accumulated net realized loss		(14,620,139	)		(6,141,861	)		(4,002,503	)		(1,558,801	)		(14,740,017	)		(32,125,006	)		(16,285,722	)
Net unrealized appreciation/ depreciation		2,851,596			5,039,868			(259	)		2,205,801			(3,711,866	)		24,036,121			27,781,958
Net Assets Applicable to Common Shareholders	$	366,519,713		$	124,975,923		$	146,179,271		$	48,661,951		$	316,482,901		$	524,440,162		$	588,412,713
Net asset value per Common Share	$	13.97		$	14.31		$	14.07		$	14.60		$	13.63		$	13.92		$	9.46
1 Investments at cost — unaffiliated	$	558,610,090		$	181,363,142		$	226,900,380		$	74,773,026		$	487,168,898		$	793,874,309		$	937,085,076
2 Investments at cost — affiliated	$	6,590,771		$	6,303,277		$	4,158,073		$	956,848		$	17,781,695		$	21,461,708		$	1,398,855
3 Represents short-term floating rate certificates issued by tender option bond trusts.
4 Preferred Shares outstanding:
Par value $0.001 per share		5,490			1,691			3,196			714			6,052			—			—
Par value $0.10 per share		—			—			—			—			—			10,986			9,753
5 Preferred Shares authorized		unlimited			unlimited			unlimited			unlimited			unlimited			1 million			10 million
6 Common Shares outstanding		26,234,135			8,734,047			10,388,497			3,333,337			23,219,157			37,667,658			62,176,380
7 Par value per Common Share	$	0.001		$	0.001		$	0.001		$	0.001		$	0.001		$	0.10		$	0.10
8 Common Shares authorized		unlimited			unlimited			unlimited			unlimited			unlimited			unlimited			150 million

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	39

Statements of Operations

Six Months Ended February 28, 2010 (Unaudited)	BlackRock Insured Municipal Income Trust (BYM)			BlackRock Insured Municipal Income Investment Trust (BAF)			BlackRock Municipal Bond Trust (BBK)			BlackRock Municipal Bond Investment Trust (BIE)			BlackRock Municipal Income Trust II (BLE)			BlackRock MuniHoldings Insured Investment Fund (MFL)			BlackRock MuniVest Fund, Inc. (MVF)
Investment Income
Interest	$	14,305,615		$	4,783,559		$	6,655,130		$	2,010,194		$	14,128,516		$	20,712,499		$	26,036,283
Income — affiliated		4,645			6,295			3,044			2,077			8,392			17,461			13,900
Total income		14,310,260			4,789,854			6,658,174			2,012,271			14,136,908			20,729,960			26,050,183
Expenses
Investment advisory		1,536,720			535,244			738,357			251,961			1,355,908			2,308,805			2,430,431
Commissions for Preferred Shares		92,908			26,049			54,072			11,777			115,800			206,744			181,404
Accounting services		52,265			26,185			22,899			12,534			44,478			109,734			160,488
Printing		31,237			10,445			13,163			4,190			28,242			23,038			24,347
Professional		29,538			25,031			24,900			23,582			30,907			41,498			41,618
Officer and Trustees		27,890			8,479			10,242			3,277			22,645			38,539			38,502
Transfer agent		17,289			9,768			13,325			9,677			19,864			33,916			44,560
Custodian		14,930			6,213			8,332			4,130			14,357			19,742			19,204
Registration		4,741			4,675			4,730			4,720			4,681			6,414			12,069
Miscellaneous		43,775			25,402			30,078			21,418			43,073			61,515			64,328
Total expenses excluding interest expense and fees		1,851,293			677,491			920,098			347,266			1,679,955			2,849,945			3,016,951
Interest expense and fees1		217,534			92,174			20,066			42,626			120,201			183,970			498,381
Total expenses		2,068,827			769,665			940,164			389,892			1,800,156			3,033,915			3,515,332
Less fees waived by advisor		(188,036	)		(68,200	)		(171,270	)		(59,210	)		(126,116	)		(187,996	)		(3,697	)
Total expenses after fees waived		1,880,791			701,465			768,894			330,682			1,674,040			2,845,919			3,511,635
Net investment income		12,429,469			4,088,389			5,889,280			1,681,589			12,462,868			17,884,041			22,538,548
Realized and Unrealized Gain (Loss)
Net realized gain (loss) from:
Investments		468,482			(3,521,043	)		2,512,087			668,747			283,158			2,082,169			8,955,872
Financial futures contracts		122,947			9,956			(6,131	)		2,987			175,372			35,842			335,746
		591,429			(3,511,087	)		2,505,956			671,734			458,530			2,118,011			9,291,618
Net change in unrealized appreciation/ depreciation on investments		9,100,243			5,247,529			5,794,509			617,375			18,423,405			9,338,467			18,708,065
Total realized and unrealized gain		9,691,672			1,736,442			8,300,465			1,289,109			18,881,935			11,456,478			27,999,683
Dividends to Preferred Shareholders From
Net investment income		(271,576	)		(83,770	)		(158,516	)		(35,488	)		(301,077	)		(544,618	)		(498,379	)
Net Increase in Net Assets Applicable to Common Shareholders Resulting from Operations	$	21,849,565		$	5,741,061		$	14,031,229		$	2,935,210		$	31,043,726		$	28,795,901		$	50,039,852
1 Related to tender option bond trusts.

See Notes to Financial Statements.
40	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Statements of Changes in Net Assets

	BlackRock Insured Municipal Income Trust (BYM)						BlackRock Insured Municipal Income Investment Trust (BAF)						BlackRock Municipal Bond Trust (BBK)
Increase (Decrease) in Net Assets Applicable to Common Shareholders:	Six Months Ended February 28, 2010 (Unaudited)			Year Ended August 31, 2009			Six Months Ended February 28, 2010 (Unaudited)			Year Ended August 31, 2009			Six Months Ended February 28, 2010 (Unaudited)			Year Ended August 31, 2009
Operations
Net investment income	$	12,429,469		$	23,833,237		$	4,088,389		$	7,960,492		$	5,889,280		$	11,803,804
Net realized gain (loss)		591,429			(5,672,531	)		(3,511,087	)		(1,547,291	)		2,505,956			(4,209,349	)
Net change in unrealized appreciation/depreciation		9,100,243			(8,812,693	)		5,247,529			(873,684	)		5,794,509			(4,343,179	)
Dividends to Preferred Shareholders from net investment income		(271,576	)		(2,513,122	)		(83,770	)		(744,761	)		(158,516	)		(1,349,183	)
Net increase in net assets applicable to Common Shareholders resulting from operations		21,849,565			6,834,891			5,741,061			4,794,756			14,031,229			1,902,093
Dividends to Common Shareholders From
Net investment income		(10,782,230	)		(19,779,705	)		(3,589,693	)		(6,275,413	)		(5,292,110	)		(9,386,250	)
Capital Share Transactions
Reinvestment of common dividends		118,279			146,402			—			—			410,394			397,817
Net Assets Applicable to Common Shareholders
Total increase (decrease) in net assets applicable to Common Shareholders		11,185,614			(12,798,412	)		2,151,368			(1,480,657	)		9,149,513			(7,086,340	)
Beginning of period		355,334,099			368,132,511			122,824,555			124,305,212			137,029,758			144,116,098
End of period	$	366,519,713		$	355,334,099		$	124,975,923		$	122,824,555		$	146,179,271		$	137,029,758
Undistributed net investment income	$	5,918,799		$	4,543,136		$	2,154,289		$	1,739,363		$	2,487,342		$	2,048,688

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	41

Statements of Changes in Net Assets (continued)

	BlackRock Municipal Bond Investment Trust (BIE)						BlackRock Municipal Income Trust II (BLE)						BlackRock MuniHoldings Insured Investment Fund (MFL)
Increase (Decrease) in Net Assets Applicable to Common Shareholders:	Six Months Ended February 28, 2010 (Unaudited)			Year Ended August 31, 2009			Six Months Ended February 28, 2010 (Unaudited)			Year Ended August 31, 2009			Six Months Ended February 28, 2010 (Unaudited)			Year Ended August 31, 2009
Operations
Net investment income	$	1,681,589		$	3,449,366		$	12,462,868		$	25,241,928		$	17,884,041		$	35,460,295
Net realized gain (loss)		671,734			(2,150,945	)		458,530			(6,728,654	)		2,118,011			(14,166,063	)
Net change in unrealized appreciation/depreciation		617,375			(388,109	)		18,423,405			(15,458,538	)		9,338,467			12,563,335
Dividends to Preferred Shareholders from net investment income		(35,488	)		(437,198	)		(301,077	)		(2,784,279	)		(544,618	)		(4,979,410	)
Net increase in net assets applicable to Common Shareholders resulting from operations		2,935,210			473,114			31,043,726			270,457			28,795,901			28,878,157
Dividends to Common Shareholders From
Net investment income		(1,476,002	)		(2,802,003	)		(11,273,491	)		(19,376,940	)		(15,368,404	)		(26,563,835	)
Capital Share Transactions
Reinvestment of common dividends		—			—			643,165			287,025			—			—
Net Assets Applicable to Common Shareholders
Total increase (decrease) in net assets applicable to Common Shareholders		1,459,208			(2,328,889	)		20,413,400			(18,819,458	)		13,427,497			2,314,322
Beginning of period		47,202,743			49,531,632			296,069,501			314,888,959			511,012,665			508,698,343
End of period	$	48,661,951		$	47,202,743		$	316,482,901		$	296,069,501		$	524,440,162		$	511,012,665
Undistributed net investment income	$	777,017		$	606,918		$	4,978,816		$	4,090,516		$	8,088,370		$	6,117,351

See Notes to Financial Statements.
42	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Statements of Changes in Net Assets (concluded)

	BlackRock MuniVest Fund, Inc. (MVF)
Increase (Decrease) in Net Assets Applicable to Common Shareholders:	Six Months Ended February 28, 2010 (Unaudited)			Year Ended August 31, 2009
Operations
Net investment income	$	22,538,548		$	43,460,100
Net realized gain		9,291,618			122,896
Net change in unrealized appreciation/depreciation		18,708,065			(2,052,514	)
Dividends to Preferred Shareholders from net investment income		(498,379	)		(3,867,803	)
Net increase in net assets applicable to Common Shareholders resulting from operations		50,039,852			37,662,679
Dividends to Common Shareholders From
Net investment income		(19,740,525	)		(33,322,841	)
Capital Share Transactions
Reinvestment of common dividends		2,224,030			522,169
Net Assets Applicable to Common Shareholders
Total increase in net assets applicable to Common Shareholders		32,523,357			4,862,007
Beginning of period		555,889,356			551,027,349
End of period	$	588,412,713		$	555,889,356
Undistributed net investment income	$	12,745,063		$	10,445,419

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	43

Statements of Cash Flows

Six Months Ended February 28, 2010 (Unaudited)	BlackRock Insured Municipal Income Trust (BYM)			BlackRock Insured Municipal Income Investment Trust (BAF)			BlackRock Municipal Bond Investment Trust (BIE)			BlackRock MuniVest Fund, Inc. (MVF)
Cash Provided by Operating Activities
Net increase in net assets resulting from operations, excluding dividends to Preferred Shareholders	$	22,121,141		$	5,824,831		$	2,970,698		$	50,538,231
Adjustments to reconcile net decrease in net assets resulting from operations to net cash provided by operating activities:
Decrease in interest receivable		290,401			64,096			89,584			812,949
(Increase) decrease in income receivable — affiliated		42			5			8			(62	)
Increase (decrease) in other assets		3,307			1,293			(72	)		(23,341	)
Increase (decrease) in investment advisory fees payable		9,327			3,366			(2,078	)		(23,213	)
(Increase) decrease in other affiliates payable		2,727			(1	)		(8	)		(28	)
(Increase) decrease in other accrued expenses payable		(10,770	)		(16,069	)		8,468			(31,284	)
(Increase) decrease in Officer’s and Trustees’ fees payable		(3,008	)		(918	)		375			23,234
Decrease in interest expense and fees payable		(129,250	)		(110,213	)		(6,015	)		(271,628	)
Net realized and unrealized gain (loss) on investments		(9,909,229	)		(1,923,341	)		(1,310,066	)		(25,049,477	)
Amortization of premium and discount on investments		(2,128,088	)		(138,258	)		(140,360	)		563,603
Proceeds from sales of long-term investments		47,071,899			22,133,361			20,344,171			210,199,405
Purchases of long-term investments		(51,411,473	)		(25,152,612	)		(19,555,812	)		(196,328,640	)
Net (purchases) sales of short-term investments		310,972			2,899,479			(956,846	)		2,705,509
Net cash provided by operating activities		6,217,998			3,585,019			1,442,047			43,115,258
Cash Used for Financing Activities
Cash receipts from trust certificates		4,750,001			—			—			19,166,634
Cash payments from trust certificates		—			(1	)		—			(42,295,916	)
Cash dividends paid to Common Shareholders		(10,781,635	)		(3,563,491	)		(1,476,002	)		(19,572,942	)
Cash dividends paid to Preferred Shareholders		(272,121	)		(81,227	)		(36,129	)		(499,074	)
Increase in custodian bank payable		—			(1,044	)		(629	)		(252	)
Cash used for financing activities		(6,303,755	)		(3,645,763	)		(1,512,760	)		(43,201,550	)
Cash
Net decrease in cash		(85,757	)		(60,744	)		(70,713	)		(86,292	)
Cash at beginning of period		85,757			60,744			70,713			86,292
Cash at end of period		—			—			—			—
Cash Flow Information
Cash paid during the period for interest	$	346,784		$	202,387		$	48,641		$	770,009

A Statement of Cash Flows is presented when a Trust had a significant amount of borrowing during the period, based on the average borrowing outstanding in relation to average total assets.

See Notes to Financial Statements.
44	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Financial Highlights BlackRock Insured Municipal Income Trust (BYM)

	Six Months Ended February 28, 2010 (Unaudited)
				Year Ended August 31,
				2009			2008			2007			2006			2005
Per Share Operating Performance
Net asset value, beginning of period	$	13.55		$	14.04		$	14.82		$	15.54		$	15.61		$	14.62
Net investment income		0.47	1		0.91	1		1.04	1		1.03			1.03			1.03
Net realized and unrealized gain (loss)		0.37			(0.55	)		(0.83	)		(0.67	)		(0.09	)		1.07
Dividends to Preferred Shareholders from:
Net investment income		(0.01	)		(0.10	)		(0.26	)		(0.28	)		(0.26	)		(0.17	)
Net realized gain		—			—			—			(0.02	)		—			—
Net increase (decrease) from investment operations		0.83			0.26			(0.05	)		0.06			0.68			1.93
Dividends and distributions to Common Shareholders from:
Net investment income		(0.41	)		(0.75	)		(0.73	)		(0.73	)		(0.75	)		(0.94	)
Net realized gain		—			—			—			(0.05	)		—			—
Total dividends and distributions to Common Shareholders		(0.41	)		(0.75	)		(0.73	)		(0.78	)		(0.75	)		(0.94	)
Net asset value, end of period	$	13.97		$	13.55		$	14.04		$	14.82		$	15.54		$	15.61
Market price, end of period	$	13.70		$	13.69		$	13.19		$	14.35		$	14.65		$	15.43
Total Investment Return2
Based on net asset value		6.21	%3		2.83	%		(0.16	)%		0.48	%		4.92	%		13.77	%
Based on market price		3.09	%3		10.58	%		(3.13	)%		3.20	%		0.07	%		17.69	%
Ratios to Average Net Assets Applicable to Common Shareholders
Total expenses4		1.14	%5		1.38	%		1.24	%		1.12	%		1.18	%		1.15	%
Total expenses after fees waived and before fees paid indirectly4		1.04	%5		1.20	%		0.98	%		0.80	%		0.84	%		0.83	%
Total expenses after fees waived and paid indirectly4		1.04	%5		1.20	%		0.98	%		0.80	%		0.84	%		0.83	%
Total expenses after fees waived and paid indirectly and excluding interest expense and fees4,6		0.92	%5		0.93	%		0.86	%		0.80	%		0.84	%		0.83	%
Net investment income		6.86	%5		7.23	%		7.08	%		6.67	%		6.75	%		6.83	%
Dividends to Preferred Shareholders		0.15	%5		0.76	%		1.80	%		1.79	%		1.69	%		1.09	%
Net investment income to Common Shareholders		6.71	%5		6.47	%		5.28	%		4.88	%		5.06	%		5.74	%
Supplemental Data
Net assets applicable to Common Shareholders, end of period (000)	$	366,520		$	355,334		$	368,133		$	388,275		$	407,338		$	408,641
Preferred Shares outstanding at $25,000 liquidation preference, end of period (000)	$	137,250		$	137,250		$	149,925		$	228,975		$	228,975		$	228,975
Portfolio turnover		10	%		18	%		39	%		17	%		60	%		57	%
Asset coverage per Preferred Share at $25,000 liquidation preference, end of period	$	91,763		$	89,725		$	86,398		$	67,402		$	69,485		$	69,622

1	Based on average shares outstanding.
2	Total investment returns based on market value, which can be significantly greater or lesser than the net asset value, may result in substantially different returns. Where applicable, total investment returns exclude the effects of sales charges and include the reinvestment of dividends and distributions.
3	Aggregate total investment return.
4	Do not reflect the effect of dividends to Preferred Shareholders.
5	Annualized.
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.

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	45

Financial Highlights BlackRock Insured Municipal Income Investment Trust (BAF)

	Six Months Ended February 28, 2010 (Unaudited)
				Year Ended August 31,
				2009			2008			2007			2006			2005
Per Share Operating Performance
Net asset value, beginning of period	$	14.06		$	14.23		$	14.68		$	15.24		$	15.26		$	14.34
Net investment income		0.47	1		0.91	1		0.99	1		1.01			1.02			1.02
Net realized and unrealized gain (loss)		0.20			(0.27	)		(0.46	)		(0.56	)		(0.07	)		0.96
Dividends to Preferred Shareholders from net investment income		(0.01	)		(0.09	)		(0.28	)		(0.31	)		(0.26	)		(0.16	)
Net increase from investment operations		0.66			0.55			0.25			0.14			0.69			1.82
Dividends to Common Shareholders from net investment income		(0.41	)		(0.72	)		(0.70	)		(0.70	)		(0.71	)		(0.90	)
Net asset value, end of period	$	14.31		$	14.06		$	14.23		$	14.68		$	15.24		$	15.26
Market price, end of period	$	14.00		$	13.01		$	12.42		$	13.55		$	13.88		$	15.30
Total Investment Return2
Based on net asset value		4.89	%3		5.36	%		2.22	%		1.17	%		5.16	%		13.13	%
Based on market price		10.90	%3		11.70	%		(3.35	)%		2.54	%		(4.48	)%		15.03	%
Ratios to Average Net Assets Applicable to Common Shareholders
Total expenses4		1.24	%5		1.60	%		1.33	%		1.19	%		1.23	%		1.22	%
Total expenses after fees waived and before fees paid indirectly4		1.13	%5		1.40	%		1.05	%		0.87	%		0.92	%		0.90	%
Total expenses after fees waived and paid indirectly4		1.13	%5		1.40	%		1.05	%		0.86	%		0.90	%		0.89	%
Total expenses after fees waived and paid indirectly and excluding interest expense and fees4,6		0.98	%5		0.98	%		0.91	%		0.86	%		0.90	%		0.89	%
Net investment income4		6.58	%5		7.04	%		6.71	%		6.70	%		6.79	%		6.85	%
Dividends to Preferred Shareholders		0.13	%5		0.66	%		1.92	%		2.05	%		1.74	%		1.06	%
Net investment income to Common Shareholders		6.45	%5		6.38	%		4.79	%		4.65	%		5.05	%		5.79	%
Supplemental Data
Net assets applicable to Common Shareholders, end of period (000)	$	124,976		$	122,825		$	124,305		$	128,215		$	133,106		$	133,221
Preferred Shares outstanding at $25,000 liquidation preference, end of period (000)	$	42,275		$	42,275		$	44,375		$	76,000		$	76,000		$	76,000
Portfolio turnover		13	%		45	%		29	%		13	%		9	%		2	%
Asset coverage per Preferred Share at $25,000 liquidation preference, end of period	$	98,908		$	97,637		$	95,044		$	67,187		$	68,792		$	68,826

1	Based on average shares outstanding.
2	Total investment returns based on market value, which can be significantly greater or lesser than the net asset value, may result in substantially different returns. Where applicable, total investment returns exclude the effects of sales charges and include the reinvestment of dividends and distributions.
3	Aggregate total investment return.
4	Do not reflect the effect of dividends to Preferred Shareholders.
5	Annualized.
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.

See Notes to Financial Statements.
46	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Financial Highlights BlackRock Municipal Bond Trust (BBK)

	Six Months Ended February 28, 2010 (Unaudited)
				Year Ended August 31,
				2009			2008			2007			2006			2005
Per Share Operating Performance
Net asset value, beginning of period	$	13.23		$	13.96		$	15.57		$	16.35		$	16.36		$	15.00
Net investment income		0.57	1		1.14	1		1.23	1		1.20			1.21			1.21
Net realized and unrealized gain (loss)		0.80			(0.83	)		(1.48	)		(0.63	)		0.18			1.36
Dividends and distributions to Preferred Shareholders from:
Net investment income		(0.02	)		(0.13	)		(0.28	)		(0.32	)		(0.25	)		(0.17	)
Net realized gain		—			—			(0.03	)		—			(0.02	)		—
Net increase (decrease) from investment operations		1.35			0.18			(0.56	)		0.25			1.12			2.40
Dividends and distributions to Common Shareholders from:
Net investment income		(0.51	)		(0.91	)		(0.95	)		(1.03	)		(1.04	)		(1.04	)
Net realized gain		—			—			(0.10	)		—			(0.09	)		—
Total dividends and distributions to Common Shareholders		(0.51	)		(0.91	)		(1.05	)		(1.03	)		(1.13	)		(1.04	)
Net asset value, end of period	$	14.07		$	13.23		$	13.96		$	15.57		$	16.35		$	16.36
Market price, end of period	$	14.37		$	13.80		$	13.89		$	16.50		$	17.89		$	17.18
Total Investment Return2
Based on net asset value		10.31	%3		2.52	%		(3.77	)%		1.09	%		7.18	%		16.63	%
Based on market price		8.01	%3		7.48	%		(9.65	)%		(2.09	)%		11.55	%		25.75	%
Ratios to Average Net Assets Applicable to Common Shareholders
Total expenses4		1.32	%5		1.51	%		1.39	%		1.28	%		1.37	%		1.35	%
Total expenses after fees waived and before fees paid indirectly4		1.08	%5		1.19	%		1.01	%		0.84	%		0.88	%		0.88	%
Total expenses after fees waived and paid indirectly4		1.08	%5		1.19	%		1.01	%		0.83	%		0.86	%		0.87	%
Total expenses after fees waived and paid indirectly and excluding interest expense and fees4,6		1.05	%5		1.10	%		0.98	%		0.83	%		0.86	%		0.87	%
Net investment income4		8.29	%5		9.67	%		8.25	%		7.36	%		7.58	%		7.73	%
Dividends to Preferred Shareholders		0.22	%5		1.11	%		1.87	%		1.94	%		1.57	%		1.08	%
Net investment income to Common Shareholders		8.07	%5		8.56	%		6.38	%		5.42	%		6.01	%		6.65	%
Supplemental Data
Net assets applicable to Common Shareholders, end of period (000)	$	146,179		$	137,030		$	144,116		$	159,900		$	166,895		$	165,863
Preferred Shares outstanding at $25,000 liquidation preference, end of period (000)	$	79,900		$	79,900		$	80,500		$	90,500		$	90,500		$	90,500
Portfolio turnover		20	%		46	%		27	%		14	%		85	%		70	%
Asset coverage per Preferred Share at $25,000 liquidation preference, end of period	$	70,739		$	67,877		$	69,766		$	69,176		$	71,114		$	70,824

1	Based on average shares outstanding.
2	Total investment returns based on market value, which can be significantly greater or lesser than the net asset value, may result in substantially different returns. Where applicable, total investment returns exclude the effects of sales charges and include the reinvestment of dividends and distributions.
3	Aggregate total investment return.
4	Do not reflect the effect of dividends to Preferred Shareholders.
5	Annualized.
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.

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	47

Financial Highlights BlackRock Municipal Bond Investment Trust (BIE)

	Six Months Ended February 28, 2010 (Unaudited)
				Year Ended August 31,
				2009			2008			2007			2006			2005
Per Share Operating Performance
Net asset value, beginning of period	$	14.16		$	14.86		$	15.45		$	16.22		$	16.31		$	15.53
Net investment income		0.50	1		1.03	1		1.16	1		1.15			1.17			1.16
Net realized and unrealized gain (loss)		0.39			(0.76	)		(0.51	)		(0.67	)		(0.06	)		0.71
Dividends and distributions to Preferred Shareholders from net investment income		(0.01	)		(0.13	)		(0.30	)		(0.32	)		(0.27	)		(0.16	)
Net increase from investment operations		0.88			0.14			0.35			0.16			0.84			1.71
Dividends to Common Shareholders from net investment income		(0.44	)		(0.84	)		(0.94	)		(0.93	)		(0.93	)		(0.93	)
Net asset value, end of period	$	14.60		$	14.16		$	14.86		$	15.45		$	16.22		$	16.31
Market price, end of period	$	13.62		$	13.20		$	14.28		$	15.82		$	16.70		$	15.95
Total Investment Return2
Based on net asset value		6.50	%3		2.43	%		2.34	%		0.95	%		5.40	%		11.58	%
Based on market price		6.57	%3		(0.64	)%		(3.95	)%		0.40	%		10.97	%		19.59	%
Ratios to Average Net Assets Applicable to Common Shareholders
Total expenses4		1.62	%5		1.71	%		1.54	%		1.43	%		1.47	%		1.49	%
Total expenses after fees waived and before fees paid indirectly4		1.38	%5		1.36	%		1.13	%		0.98	%		1.00	%		1.02	%
Total expenses after fees waived and paid indirectly4		1.38	%5		1.36	%		1.13	%		0.96	%		0.98	%		1.00	%
Total expenses after fees waived and paid indirectly and excluding interest expense and fees4,6		1.20	%5		1.25	%		1.09	%		0.96	%		0.98	%		1.00	%
Net investment income4		6.99	%5		7.98	%		7.52	%		7.22	%		7.28	%		7.24	%
Dividends to Preferred Shareholders		0.15	%5		1.01	%		1.99	%		2.01	%		1.70	%		1.01	%
Net investment income to Common Shareholders		6.84	%5		6.97	%		5.53	%		5.21	%		5.58	%		6.23	%
Supplemental Data
Net assets applicable to Common Shareholders, end of period (000)	$	48,662		$	47,203		$	49,532		$	51,384		$	53,798		$	53,990
Preferred Shares outstanding at $25,000 liquidation preference, end of period (000)	$	17,850		$	17,850		$	26,175		$	29,775		$	29,775		$	29,775
Portfolio turnover		26	%		71	%		30	%		23	%		6	%		2	%
Asset coverage per Preferred Share at $25,000 liquidation preference, end of period	$	93,155		$	91,112		$	72,318		$	68,149		$	70,173		$	70,343

1	Based on average shares outstanding.
2	Total investment returns based on market value, which can be significantly greater or lesser than the net asset value, may result in substantially different returns. Where applicable, total investment returns exclude the effects of sales charges and include the reinvestment of dividends and distributions.
3	Aggregate total investment return.
4	Do not reflect the effect of dividends to Preferred Shareholders.
5	Annualized.
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.

See Notes to Financial Statements.
48	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Financial Highlights BlackRock Municipal Income Trust II (BLE)

	Six Months Ended February 28, 2010 (Unaudited)
				Year Ended August 31,
				2009			2008			2007			2006			2005
Per Share Operating Performance
Net asset value, beginning of period	$	12.78		$	13.60		$	15.08		$	15.82		$	15.75		$	14.34
Net investment income		0.54	1		1.09	1		1.17	1		1.17			1.18			1.20
Net realized and unrealized gain (loss)		0.81			(0.95	)		(1.50	)		(0.66	)		0.18			1.38
Dividends to Preferred Shareholders from net investment income		(0.01	)		(0.12	)		(0.30	)		(0.32	)		(0.28	)		(0.17	)
Net increase (decrease) from investment operations		1.34			0.02			(0.63	)		0.19			1.08			2.41
Dividends to Common Shareholders from net investment income		(0.49	)		(0.84	)		(0.85	)		(0.93	)		(1.01	)		(1.00	)
Net asset value, end of period	$	13.63		$	12.78		$	13.60		$	15.08		$	15.82		$	15.75
Market price, end of period	$	13.54		$	13.45		$	13.27		$	15.05		$	17.22		$	15.73
Total Investment Return2
Based on net asset value		10.57	%3		1.54	%		(4.15	)%		1.02	%		7.04	%		17.56	%
Based on market price		4.36	%3		9.52	%		(6.29	)%		(7.38	)%		16.66	%		20.95	%
Ratios to Average Net Assets Applicable to Common Shareholders
Total expenses4		1.17	%6		1.36	%		1.24	%		1.12	%		1.18	%		1.17	%
Total expenses after fees waived and before fees paid indirectly4		1.09	%6		1.19	%		1.07	%		0.90	%		0.94	%		0.93	%
Total expenses after fees waived and paid indirectly4		1.09	%6		1.19	%		1.07	%		0.89	%		0.94	%		0.93	%
Total expenses after fees waived and paid indirectly and excluding interest expense and fees4,5		1.01	%6		1.05	%		1.00	%		0.89	%		0.94	%		0.93	%
Net investment income4		8.10	%6		9.69	%		8.09	%		7.43	%		7.66	%		8.00	%
Dividends to Preferred Shareholders		0.20	%6		1.07	%		2.04	%		2.01	%		1.78	%		1.15	%
Net investment income to Common Shareholders		7.90	%6		8.62	%		6.05	%		5.42	%		5.88	%		6.85	%
Supplemental Data
Net assets applicable to Common Shareholders, end of period (000)	$	316,483		$	296,070		$	314,889		$	347,563		$	362,608		$	359,020
Preferred Shares outstanding at $25,000 liquidation preference, end of period (000)	$	151,300		$	151,300		$	166,050		$	205,550		$	205,550		$	205,550
Portfolio turnover		18	%		19	%		21	%		12	%		68	%		49	%
Asset coverage per Preferred Share at $25,000 liquidation preference, end of period	$	77,295		$	73,923		$	72,419		$	67,279		$	69,110		$	68,672

1	Based on average shares outstanding.
2	Total investment returns based on market value, which can be significantly greater or lesser than the net asset value, may result in substantially different returns. Where applicable, total investment returns exclude the effects of sales charges and include the reinvestment of dividends and distributions.
3	Aggregate total investment return.
4	Do not reflect the effect of dividends to Preferred Shareholders.
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	FEBRUARY 28, 2010	49

Financial Highlights BlackRock MuniHoldings Insured Investment Fund (MFL)

	Six Months Ended February 28, 2010 (Unaudited)
				Year Ended August 31,
				2009			2008			2007			2006			2005
Per Share Operating Performance
Net asset value, beginning of period	$	13.57		$	13.50		$	14.09		$	14.75		$	15.32		$	15.37
Net investment income1		0.47			0.94			1.01			1.07			1.04			1.09
Net realized and unrealized gain (loss)		0.30			(0.03	)		(0.61	)		(0.66	)		(0.47	)		0.05
Dividends to Preferred Shareholders from net investment income		(0.01	)		(0.13	)		(0.32	)		(0.35	)		(0.30	)		(0.18	)
Net increase from investment operations		0.76			0.78			0.08			0.06			0.27			0.96
Dividends to Common Shareholders from net investment income		(0.41	)		(0.71	)		(0.67	)		(0.72	)		(0.84	)		(1.01	)
Net asset value, end of period	$	13.92		$	13.57		$	13.50		$	14.09		$	14.75		$	15.32
Market price, end of period	$	13.08		$	12.63		$	11.61		$	12.86		$	14.37		$	15.75
Total Investment Return2
Based on net asset value		5.82	%3		7.36	%		1.16	%		0.59	%		2.10	%		6.49	%
Based on market price		6.84	%3		16.19	%		(4.68	)%		(5.76	)%		(3.24	)%		13.39	%
Ratios to Average Net Assets Applicable to Common Shareholders
Total expenses4		1.17	%5		1.32	%		1.54	%		1.54	%		1.46	%		1.41	%
Total expenses after fees waived and before fees paid indirectly4		1.10	%5		1.20	%		1.42	%		1.46	%		1.38	%		1.35	%
Total expenses after fees waived and paid indirectly4		1.10	%5		1.20	%		1.42	%		1.46	%		1.38	%		1.35	%
Total expenses after fees waived and paid indirectly and excluding interest expense and fees4,6		1.03	%5		1.07	%		1.13	%		1.12	%		1.12	%		1.11	%
Net investment income4		6.89	%5		7.48	%		7.23	%		7.30	%		7.08	%		7.11	%
Dividends to Preferred Shareholders		0.21	%5		1.05	%		2.31	%		2.40	%		2.00	%		1.15	%
Net investment income to Common Shareholders		6.65	%5		6.43	%		4.92	%		4.90	%		5.08	%		5.96	%
Supplemental Data
Net assets applicable to Common Shareholders, end of period (000)	$	524,440		$	511,013		$	508,698		$	530,903		$	555,494		$	576,931
Preferred Shares outstanding at $25,000 liquidation preference, end of period (000)	$	274,650		$	274,650		$	296,125		$	363,250		$	363,250		$	363,250
Portfolio turnover		24	%		40	%		25	%		22	%		43	%		26	%
Asset coverage per Preferred Share at $25,000 liquidation preference, end of period	$	72,738		$	71,516		$	67,958		$	61,555	7	$	63,240	7	$	64,711	7

1	Based on average shares outstanding.
2	Total investment returns based on market value, which can be significantly greater or lesser than the net asset value, may result in substantially different returns. Where applicable, total investment returns exclude the effects of any sales charges and include the reinvestment of dividends and distributions.
3	Aggregate total investment return.
4	Do not reflect the effect of dividends to Preferred Shareholders.
5	Annualized.
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	Prior year amounts have been recalculated to conform with current period presentation.

See Notes to Financial Statements.
50	SEMI-ANNUAL REPORT	FEBRUARY 28, 2010

Financial Highlights BlackRock MuniVest Fund, Inc. (MVF)

	Six Months Ended February 28, 2010 (Unaudited)
				Year Ended August 31,
				2009			2008			2007			2006			2005
Per Share Operating Performance
Net asset value, beginning of period	$	8.98		$	8.91		$	9.39		$	9.93		$	10.23		$	9.91
Net investment income1		0.36			0.70			0.67			0.73			0.70			0.74
Net realized and unrealized gain (loss)		0.45			(0.03	)		(0.45	)		(0.55	)		(0.23	)		0.35
Dividends to Preferred Shareholders from net investment income		(0.01	)		(0.06	)		(0.18	)		(0.20	)		(0.17	)		(0.10	)
Net increase (decrease) from investment operations		0.80			0.61			0.04			(0.02	)		0.30			0.99
Dividends to Common Shareholders from net investment income		(0.32	)		(0.54	)		(0.52	)		(0.52	)		(0.60	)		(0.67	)
Net asset value, end of period	$	9.46		$	8.98		$	8.91		$	9.39		$	9.93		$	10.23
Market price, end of period	$	9.64		$	8.91		$	8.33		$	9.35		$	9.66		$	10.15
Total Investment Return2
Based on net asset value		8.97	%3		8.18	%		0.51	%		(0.30	)%		3.27	%		10.64	%
Based on market price		11.91	%3		14.81	%		(5.63	)%		2.05	%		1.26	%		16.97	%
Ratios to Average Net Assets Applicable to Common Shareholders
Total expenses4		1.22	%5		1.53	%		1.58	%		1.66	%		1.60	%		1.45	%
Total expenses after fees waived and before fees paid indirectly4		1.22	%5		1.50	%		1.58	%		1.66	%		1.60	%		1.45	%
Total expenses after fees waived and paid indirectly and excluding interest expense and fees4,6		1.04	%5		1.14	%		1.10	%		1.02	%		1.04	%		1.02	%
Net investment income4		7.81	%5		8.74	%		7.34	%		7.33	%		7.11	%		7.38	%
Dividends to Preferred Shareholders		0.17	%5		0.78	%		1.94	%		1.98	%		1.72	%		1.02	%
Net investment income to Common Shareholders		7.64	%5		7.96	%		5.40	%		5.35	%		5.39	%		6.36	%
Supplemental Data
Net assets applicable to Common Shareholders, end of period (000)	$	588,413		$	555,889		$	551,027		$	579,079		$	609,612		$	627,562
Preferred Shares outstanding at $25,000 liquidation preference, end of period (000)	$	243,825		$	243,825		$	275,700		$	334,000		$	334,000		$	334,000
Portfolio turnover		23	%		31	%		41	%		39	%		56	%		49	%
Asset coverage per Preferred Share at $25,000 liquidation preference, end of period	$	85,334		$	81,999		$	74,993		$	68,380	7	$	70,654	7	$	71,973	7

1	Based on average shares outstanding.
2	Total investment returns based on market value, which can be significantly greater or lesser than the net asset value, may result in substantially different returns. Where applicable, total investment returns exclude the effects of sales charges and include the reinvestment of dividends and distributions.
3	Aggregate total investment return.
4	Do not reflect the effect of dividends to Preferred Shareholders.
5	Annualized.
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	Prior year amounts have been recalculated to conform with current period presentation.

See Notes to Financial Statements.
SEMI-ANNUAL REPORT	FEBRUARY 28, 2010	51

Notes to Financial Statements (Unaudited)

1. Organization and Significant Accounting Policies:

BlackRock Insured Municipal Income Trust (“BYM”), BlackRock Insured Municipal Income Investment Trust (“BAF”) (collectively the “Insured Trusts”), BlackRock Municipal Bond Trust (“BBK”), BlackRock Municipal Bond Investment Trust (“BIE”) (collectively the “Bond Trusts”) and BlackRock Municipal Income Trust II (“BLE”) are organized as Delaware statutory trusts. BlackRock MuniHoldings Insured Investment Fund (“MFL”) and BlackRock MuniVest Fund, Inc. (“MVF”) (all, collectively the “Trusts”) are organized as a Massachusetts business trust and as a Maryland corporation, respectively. BYM, BBK and BLE are registered under the Investment Company Act of 1940, as amended (the “1940 Act”) as diversified, closed-end management investment companies. BAF, BIE, MFL and MVF are registered under the 1940 Act as non-diversified, closed-end management investment companies. The Trusts’ financial statements are prepared in conformity with accounting principles generally 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 Boards of Directors and the Boards of Trustees of the Trusts are referred to throughout this report as the “Board of Trustees” or the “Board.” The Trusts determine and make available for publication the net asset value of their Common Shares on a daily basis.

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

Valuation: The Trusts’ policy is to fair value their financial instruments at market value. Municipal investments (including commitments 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 Trust’s 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 securities with remaining maturities of 60 days or less may be valued at amortized cost, which approximates fair value. Investments in open-end investment companies are valued at net asset value each business day.

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 or is not available, the investment will be valued by a method approved by each Trust’s Board as reflecting fair value (“Fair Value Assets”). When determining the price for Fair Value Assets, the investment advisor and/or the sub-advisor seeks to determine the price that each Trust 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 sub-advisor deems relevant. The pricing of all Fair Value Assets is subsequently reported to the Board or a committee thereof.

Forward Commitments and When-Issued Delayed Delivery Securities: Each Trust 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 Trusts may purchase securities under such conditions 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 Trusts 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 purchasing a security on a delayed delivery basis, the Trusts assume the rights and risks of ownership of the security, including the risk of price and yield fluctuations. In the event of default by the counterparty, the Trusts’ maximum amount of loss is the unrealized gain of the commitment, which is shown on the Schedules of Investments, if any.

Municipal Bonds Transferred to Tender Option Bond Trusts: The Trusts 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 bonds. Other funds managed by the investment advisor may also contribute municipal bonds to a TOB into which a Trust has contributed bonds. 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 Trust include the right of the Trust (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 bonds from the TOB to the Trust. The TOB may also be terminated without the consent of the Trust upon the occurrence of certain events as defined in the TOB agreements. Such termination events may include the bankruptcy or default of the municipal bond, a substantial downgrade in credit quality of the municipal bond, the inability of the TOB to obtain quarterly or annual renewal of the liquidity support agreement, a substantial decline in market value of the municipal bond or the inability to remarket the short-term floating rate certificates to third party investors.

The cash received by the TOB from the sale of the short-term floating rate certificates, less transaction expenses, is paid to the Trust, which typically invests the cash in additional municipal bonds. Each Trust’s transfer of the municipal bonds to a TOB is accounted for as a secured borrowing, therefore the municipal bonds deposited into a TOB are presented in the Trusts’ Schedules of Investments and the proceeds from the issuance of the short-term floating rate certificates are shown as trust certificates in the Statements of Assets and Liabilities.

Interest income from the underlying security is recorded by the Trusts 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 Trusts. 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 February 28, 2010, the aggregate value of the underlying municipal bonds

52 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

Notes to Financial Statements (continued)

transferred to TOBs, the related liability for trust certificates and the range of interest rates on the liability for trust certificates were as follows:

	Underlying Municipal Bonds Transferred to TOBs		Liability for Trust Certificates		Range of Interest Rates
BYM	$	118,433,828	$	63,475,997	0.19% – 0.34%
BAF	$	48,980,189	$	28,697,356	0.21% – 0.34%
BBK	$	11,716,983	$	5,899,148	0.22% – 0.31%
BIE	$	22,624,414	$	11,821,747	0.16% – 0.25%
BLE	$	64,626,461	$	35,563,189	0.16% – 0.31%
MFL	$	95,036,947	$	49,760,534	0.21% – 0.64%
MVF	$	246,652,387	$	129,183,699	0.19% – 0.38%

For the six months ended February 28, 2010, the Trusts’ average trust certificates outstanding and the daily weighted average interest rate, including fees, were as follows:

	Average Trust Certificates Outstanding			Daily Weighted Average Interest Rate
BYM		$	61,011,909	0.72	%
BAF		$	28,697,356	0.65	%
BBK		$	5,899,148	0.69	%
BIE		$	11,821,747	0.73	%
BLE		$	35,563,189	0.68	%
MFL		$	48,326,609	0.77	%
MVF		$	154,417,199	0.65	%

Should short-term interest rates rise, the Trusts’ investments in TOBs may adversely affect the Trusts’ investment income and distributions to Common Shareholders. Also, fluctuations in the market value of municipal bonds deposited into the TOB may adversely affect the Trusts’ net asset value per share.

Zero-Coupon Bonds: Each Trust 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 Trusts either deliver collateral or segregate assets in connection with certain investments (e.g., financial futures contracts), each Trust will, consistent with SEC rules and/or certain interpretive letters issued by the SEC, segregate collateral or 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, each party has requirements to deliver/deposit securities as collateral for certain investments.

Investment Transactions and Investment Income: For financial reporting purposes, investment transactions are recorded on the dates the transactions are entered into (the trade dates). Realized gains and losses on investment transactions are determined on the identified cost basis. Dividend income is recorded on the ex-dividend dates. Interest income is recognized on the accrual basis. Each Trust amortizes all premiums and discounts on debt securities.

Dividends and Distributions: Dividends from net investment income are declared 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 6.

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

Each Trust files US federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Trusts’ US federal tax returns remain open for the four years ended August 31, 2009. The statutes of limitations on the Trusts’ state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Recent Accounting Standards: In June 2009, amended guidance was issued by the Financial Accounting Standards Board (“FASB”) for transfers of financial assets. This guidance is intended to improve the relevance, representational faithfulness and comparability of the information that a reporting entity provides in its financial statements about a transfer of financial assets; the effects of a transfer on its financial position, financial performance, and cash flows; and a transferor’s continuing involvement, if any, in transferred financial assets. The amended guidance is effective for financial statements for fiscal years and interim periods beginning after November 15, 2009. Earlier application is prohibited. The recognition and measurement provisions of this guidance must be applied to transfers occurring on or after the effective date. Additionally, the enhanced disclosure provisions of the amended guidance should be applied to transfers that occurred both before and after the effective date of this guidance. The impact of this guidance on the Trusts’ financial statements and disclosures, if any, is currently being assessed.

In January 2010, the FASB issued amended guidance to improve disclosure about fair value measurements which will require additional disclosures about transfers into and out of Levels 1 and 2 and separate disclosures about purchases, sales, issuances and settlements in the reconciliation for fair value measurements using significant unobservable inputs (Level 3). It also clarifies existing disclosure requirements relating to the levels of disaggregation for fair value measurement and inputs and valuation techniques used to measure fair value. The amended guidance is effective for financial statements for fiscal years and interim periods beginning after December 15, 2009 except for

SEMI-ANNUAL REPORT FEBRUARY 28, 2010 53

Notes to Financial Statements (continued)

disclosures about purchases, sales, issuances and settlements in the rollfor-ward of activity in Level 3 fair value measurements, which are effective for fiscal years beginning after December 15, 2010 and for interim periods within those fiscal years. The impact of this guidance on the Trusts’ financial statements and disclosures is currently being assessed.

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

The deferred compensation plan is not funded and obligations thereunder represent general unsecured claims against the general assets of each Trust. Each Trust may, however, elect to invest in common shares of other certain BlackRock Closed-End Funds selected by the Independent Trustees in order to match its deferred compensation obligations. Investments to cover each Trust’s deferred compensation liability, if any, are included in other assets in the Statements of Assets and Liabilities. Dividends and distributions from the BlackRock Closed-End Funds investments under the plan are included in income — affiliated in the Statements of Operations.

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

2. Derivative Financial Instruments:

The Trusts may engage in various portfolio investment strategies both to increase the return of the Trusts and to economically hedge, or protect, exposure to certain risks such as interest rate risk. Losses may arise if the value of the contract decreases due to an unfavorable change in the price of the underlying instrument or if the counterparty does not perform under the contract. To the extent amounts due to the Trust from its counterparties are not fully collateralized contractually or otherwise, the Trust bears the risk of loss from counterparty non-performance. See Note 1 “Segregation and Collateralization” for information with respect to collateral practices. Counterparty risk related to exchange-traded financial futures contracts is minimal because of the protection against default provided by the exchanges on which they trade.

Financial Futures Contracts: The Trusts may purchase or sell financial futures contracts and options on financial futures contracts to gain exposure to, or economically hedge against, changes in interest rates (interest rate risk). Financial futures contracts are contracts for delayed delivery of securities at a specific future date and at a specific price or yield. Pursuant to the contract, the Trusts 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 payments are known as margin variation and are recognized by the Trusts as unrealized gains or losses. When the contract is closed, the Trusts 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 financial futures transactions involves the risk of an imperfect correlation in the movements in the price of financial futures contracts, interest rates and the underlying assets.

Derivative Instruments Categorized by Risk Exposure:

The Effect of Derivative Instruments on the Statements of Operations Six Months Ended February 28, 2010
Net Realized Gain (Loss) from
	BYM		BAF		BBK			BIE		BLE		MFL		MVF
Interest rate contracts:
Financial futures contracts	$	122,947	$	9,956	$	(6,131	)	$	2,987	$	175,372	$	35,842	$	335,746
For the six months ended February 28, 2010, the average quarterly balance of outstanding derivative financial instruments was as follows:
	BYM		BAF		BBK			BIE		BLE		MFL		MVF
Financial futures contracts:
Average number of contracts purchased		11		5		5			2		9		18		22
Average number of contracts sold		63		—		34			—		54		—		118
Average notional value of contracts purchased	$	1,265,024	$	575,011	$	517,510		$	172,503	$	977,519	$	2,070,040	$	2,472,547
Average notional value of contracts sold	$	7,489,136		—	$	3,997,012			—	$	6,428,139		—	$	13,987,156

54 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

Notes to Financial Statements (continued)

3. Investment Advisory Agreement and Other Transactions with Affiliates:

The PNC Financial Services Group, Inc. (“PNC”), Bank of America Corporation (“BAC”) and Barclays Bank PLC (“Barclays”) are the largest stockholders of BlackRock, Inc. (“BlackRock”). Due to the ownership structure, PNC is an affiliate for 1940 Act purposes, but BAC and Barclays are not.

Each Trust entered into an Investment Advisory Agreement with BlackRock Advisors, LLC (the “Manager”), the Trusts’ investment advisor, an indirect, wholly owned subsidiary of BlackRock, to provide investment advisory and administration services.

The Manager is responsible for the management of each Trust’s portfolio and provides the necessary personnel, facilities, equipment and certain other services necessary to the operations of each Trust. For such services, each Trust pays the Manager a monthly fee of the Trust’s average weekly (daily for MFL and MVF) net assets. Average daily or weekly net assets are the average daily or weekly value of each Trust’s total assets minus the sum of its accrued liabilities. Fees accrue at the following annual rates:

BYM	0.55	%
BAF	0.55	%
BBK	0.65	%
BIE	0.65	%
BLE	0.55	%
MFL	0.55	%
MVF	0.50	%

The Manager has voluntarily agreed to waive a portion of the investment advisory fee with respect to the Insured Trusts at an annual rate of 0.05% of average weekly value of net assets through October 2010. With respect to the Bond Trusts, the waiver, as a percentage of average weekly net assets is 0.15% through April 2010, 0.10% through April 2011 and 0.05% through April 2012. With respect to BLE, the waiver, as a percentage of average weekly assets, is 0.05% through July 2012. With respect to MFL, the Manager waived its investment advisory fees on the proceeds of Preferred Shares and TOBs that exceed 35% of the average daily net assets. For the six months ended February 28, 2010, the Manager waived the following amounts, which are included in fees waived by advisor in the Statements of Operations:

	Fees Waived by Manager
BYM		$	187,185
BAF		$	65,252
BBK		$	170,391
BIE		$	58,145
BLE		$	106,606
MFL		$	182,830

The Manager has voluntarily agreed to waive its advisory fees by the amount of investment advisory fees each Trust pays to the Manager indirectly through its investment in affiliated money market funds; however, the Manager does not waive its advisory fees by the amount of investment advisory fees through its investment in other affiliated investment companies. These amounts are included in fees waived by advisor in the Statements of Operations. For the six months ended February 28, 2010, the amounts waived were as follows:

	Fees Waived by Manager
BYM		$	851
BAF		$	2,948
BBK		$	879
BIE		$	1,065
BLE		$	19,510
MFL		$	5,166
MVF		$	3,697

The Manager has entered into a separate sub-advisory agreement with BlackRock Financial Management, Inc. (“BFM”), an affiliate of the Manager, with respect to the Insured Trusts, Bond Trusts and BLE, and BlackRock Investment Management, LLC (“BIM”), an affiliate of the Manager, with respect to MFL and MVF, under which the Manager pays BFM and BIM for services they provide, a monthly fee that is a percentage of the investment advisory fee paid by the Trust to the Manager.

For the six months ended February 28, 2010, certain Trusts reimbursed the Manager for certain accounting services, which are included in accounting services in the Statements of Operations.

	Reimbursement
BYM		$	5,638
BAF		$	1,957
BBK		$	2,244
BIE		$	781
BLE		$	4,985
MFL		$	7,965
MVF		$	9,184

Certain officers and/or trustees of the Trusts are officers and/or directors of BlackRock or its affiliates. The Trusts reimburse the Manager for compensation paid to the Trusts’ Chief Compliance Officer.

4. Investments:

Purchases and sales of investments, excluding short-term securities, for the six months ended February 28, 2010 were as follows:

	Purchases		Sales
BYM	$	55,476,868	$	52,703,520
BAF	$	24,275,424	$	23,656,740
BBK	$	45,750,070	$	49,205,138
BIE	$	19,748,855	$	19,956,937
BLE	$	84,492,907	$	79,095,478
MFL	$	223,138,362	$	184,208,785
MVF	$	241,370,132	$	219,736,015

5. Concentration, Market and Credit Risk:

Each Trust invests a substantial amount of its assets in issuers located in a single state or limited number of states. Please see the Schedules of Investments for concentrations in specific states.

SEMI-ANNUAL REPORT FEBRUARY 28, 2010 55

Notes to Financial Statements (continued)

Many municipalities insure repayment of their bonds, which may reduce the potential for loss due to credit risk. 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 obligation.

In the normal course of business, the Trusts invest in securities and enter into transactions where risks exist due to fluctuations in the market (market risk) or failure of the issuer of a security to meet all its obligations (credit risk). The value of securities held by the Trusts may decline in response to certain events, including those directly involving the issuers whose securities are owned by the Trusts; conditions affecting the general economy; overall market changes; local, regional or global political, social or economic instability; and currency and interest rate and price fluctuations. Similar to credit risk, the Trusts may be exposed to counterparty risk, or the risk that an entity with which the Trusts have unsettled or open transactions may default. Financial assets, which potentially expose the Trusts to credit and counterparty risks, consist principally of investments and cash due from counterparties. The extent of the Trusts’ exposure to credit and counterparty risks with respect to these financial assets is generally approximated by their value recorded in the Trusts’ Statements of Assets and Liabilities, less any collateral held by the Trusts.

6. Capital Share Transactions:

The Insured Trusts, the Bond Trusts and BLE are authorized to issue an unlimited number of shares, including Preferred Shares, par value $0.001 per share, all of which were initially classified as Common Shares. Each Trust’s Board is authorized, however, to reclassify any unissued shares without approval of Common Shareholders.

MFL is authorized to issue an unlimited number of shares, including 1 million Preferred Shares, par value $0.10 per share.

MVF is authorized to issue 160 million shares, 150 million of which were initially classified as Common Shares, par value $0.10 per share and 10 million of which were classified as Preferred Shares, par value $0.10 per share.

Common Shares

During the six months ended February 28, 2010 and the year ended August 31, 2009, shares issued and outstanding increased by the following amounts as a result of dividend reinvestment:

	Six Months Ended February 28, 2010	Year Ended August 31, 2009
BYM	8,697	11,216
BBK	29,889	32,485
BLE	48,811	23,758
MVF	240,436	60,788

Shares issued and outstanding remained constant during the six months ended February 28, 2010 and the year ended August 31, 2009 for BAF, BIE and MFL.

Preferred Shares

The Preferred Shares are redeemable at the option of each Trust, in whole or in part, on any dividend payment date at their liquidation preference per share plus any accumulated and unpaid dividends whether or not declared. The Preferred Shares are also subject to mandatory redemption at their liquidation preference plus any accumulated and unpaid dividends, whether or not declared, if certain requirements relating to the composition of the assets and liabilities of a Trust, as set forth in each Trust’s Articles Supplementary/Statement of Preferences/Certificate of Designation (the “Governing Instrument”), are not satisfied.

From time to time in the future, each Trust that has issued Preferred Shares may effect repurchases of such shares at prices below their liquidation preference as agreed upon by the Trust and seller. Each Trust also may redeem such shares from time to time as provided in the applicable Governing Instrument. Each Trust intends to effect such redemptions and/or repurchases to the extent necessary to maintain applicable asset coverage requirements or for such other reasons as the Board may determine.

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 Trustees for each Trust. In addition, the 1940 Act requires that along with approval by shareholders that might otherwise be required, 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 a Trust’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 investment company.

The Trusts had the following series of Preferred Shares outstanding, effective yields and reset frequency at February 28, 2010:

	Series		Preferred Shares	Effective Yield		Reset Frequency Days
BYM		M-7	1,830	0.37	%	7
		R-7	1,830	0.32	%	7
		F-7	1,830	0.37	%	7
BAF		M-7	1,691	0.37	%	7
BBK		T-7	1,598	0.35	%	7
		R-7	1,598	0.32	%	7
BIE		W-7	714	0.32	%	7
BLE		M-7	1,513	0.37	%	7
		T-7	1,513	0.35	%	7
		W-7	1,513	0.32	%	7
		R-7	1,513	0.32	%	7
MFL		A	1,584	0.35	%	7
		B	2,642	0.37	%	7
		C	2,601	0.37	%	7
		D	1,633	0.32	%	7
		E	2,526	0.32	%	7
MVF		A	1,460	0.19	%	28
		B	1,460	0.21	%	28
		C	1,460	0.17	%	28
		D	1,460	0.19	%	28
		E	2,190	0.17	%	7
		F	1,723	1.42	%	7

56 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

Notes to Financial Statements (continued)

Dividends on seven-day Preferred Shares are cumulative at a rate which is reset every seven days based on the results of an auction. If the Preferred Shares fail to clear the auction on an auction date, the affected Trust is required to pay the maximum applicable rate on the Preferred Shares to holders of such shares for successive dividend periods until such time as the shares are successfully auctioned. The maximum applicable rate on all series of Preferred Shares (except for MVF) is the higher of 110% of AA commercial paper rate or 110% of 90% of the Kenney S&P 30-Day High Grade Index rate divided by 1.00 minus the marginal tax rate. The maximum applicable rate on the Preferred Shares for MVF for Series A, B, C, D and E is 110% of the interest equivalent of the 60-day commercial paper rate and for Series F is the higher of 110% plus or times (i) the Telerate/BBA LIBOR or (ii) 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 for each Trust for the six months ended February 28, 2010 were as follows:

	Series	Low	High	Average
BYM	M-7	0.24%	0.56%	0.40%
	R-7	0.24%	0.56%	0.40%
	F-7	0.24%	0.56%	0.40%
BAF	M-7	0.24%	0.56%	0.40%
BBK	T-7	0.26%	0.52%	0.38%
	R-7	0.24%	0.56%	0.39%
BIE	W-7	0.26%	0.53%	0.39%
BLE	M-7	0.24%	0.56%	0.40%
	T-7	0.26%	0.53%	0.40%
	W-7	0.26%	0.53%	0.40%
	R-7	0.24%	0.54%	0.40%
MFL	A	0.26%	0.52%	0.40%
	B	0.24%	0.56%	0.40%
	C	0.43%	0.56%	0.40%
	D	0.26%	0.53%	0.40%
	E	0.24%	0.56%	0.40%
MVF	A	0.15%	0.20%	0.18%
	B	0.13%	0.21%	0.17%
	C	0.14%	0.22%	0.18%
	D	0.14%	0.19%	0.18%
	E	0.13%	0.33%	0.18%
	F	1.34%	1.57%	1.47%

Since February 13, 2008, the Preferred Shares of each Trust failed to clear any of their auctions. As a result, the Preferred Shares dividend rates were reset to the maximum applicable rate, which ranged from 0.13% to 1.57% for the six months ended February 28, 2010. A failed auction is not an event of default for the Trusts but it has a negative impact on the liquidity of Preferred Shares. A failed auction occurs when there are more sellers of a Trust’s auction rate preferred shares than buyers. A successful auction for each Trust’s Preferred Shares may not occur for some time, if ever, and even if liquidity does resume, Preferred Shareholders may not have the ability to sell the Preferred Shares at their liquidation preference.

The Trusts may not declare dividends or make other distributions on Common Shares or purchase any such shares if, at the time of the declaration, distribution or purchase, asset coverage with respect to the outstanding Preferred Shares is less than 200%.

The Trusts pay commissions of 0.25% on the aggregate principal amount of all shares that successfully clear their auctions and 0.15% on the aggregate principal amount of all shares that fail to clear their auctions. Certain broker dealers have individually agreed to reduce commissions for failed auctions.

During the year ended August 31, 2009, certain Trusts 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:

	Series		Redemption Date		Shares Redeemed	Aggregate Principal
BYM		M-7		7/14/09	169	$	4,225,000
		R-7		7/10/09	169	$	4,225,000
		F-7		7/13/09	169	$	4,225,000
BAF		M-7		7/14/09	84	$	2,100,000
BBK		T-7		7/08/09	12	$	300,000
		R-7		7/10/09	12	$	300,000
BIE		W-7		7/09/09	333	$	8,325,000
BLE		M-7		7/14/09	147	$	3,675,000
		T-7		7/08/09	148	$	3,700,000
		W-7		7/09/09	147	$	3,675,000
		R-7		7/10/09	148	$	3,700,000
MFL		A		7/08/09	124	$	3,100,000
		B		7/06/09	207	$	5,175,000
		C		7/07/09	203	$	5,075,000
		D		7/09/09	128	$	3,200,000
		E		7/06/09	197	$	4,925,000
MVF		A		6/29/09	191	$	4,775,000
		B		7/06/09	191	$	4,775,000
		C		7/13/09	191	$	4,775,000
		D		7/20/09	191	$	4,775,000
		E		6/29/09	286	$	7,150,000
		F		7/08/09	225	$	5,625,000

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

Preferred Shares issued and outstanding remained constant for the six months ended February 28, 2010 for all Trusts.

SEMI-ANNUAL REPORT FEBRUARY 28, 2010 57

Notes to Financial Statements (concluded)

7. Capital Loss Carryforwards:

As of August 31, 2009, the Trusts had capital loss carryforwards available to offset future realized capital gains through the indicated expiration dates:

Expires August 31,		BYM		BAF		BBK		BIE		BLE		MFL		MVF
2012		—		—		—		—	$	5,097,889	$	1,836,991		—
2013		—	$	178,996		—		—		—		7,986,138		—
2015	$	1,544,099		—		—	$	30,026		—		—		—
2016		3,217,765		250,838	$	1,160,689		—		1,648,836		—	$	5,453,226
2017		6,430,212		—		2,225,455		—		3,397,830		6,481,433		8,969,669
Total	$	11,192,076	$	429,834	$	3,386,144	$	30,026	$	10,144,555	$	16,304,562	$	14,422,895

8. Subsequent Events:

Management’s evaluation of the impact of all subsequent events on the Trusts’ financial statements was completed through the date the financial statements were issued and the following items were noted:

Each Trust paid a net investment income dividend on April 1, 2010 to Common Shareholders of record on March 15, 2010 as follows:

	Common Dividend Per Share
BYM	$    0.072000
BAF	$    0.073500
BBK	$    0.085000
BIE	$     0.078800
BLE	$    0.081000
MFL	$    0.073000
MVF	$    0.054500

The dividends declared on Preferred Shares for the period March 1, 2010 to March 31, 2010 were as follows:

	Series		Dividends Declared
BYM		M-7	$	13,600
		R-7	$	13,699
		F-7	$	13,513
BAF		M-7	$	12,567
BBK		T-7	$	11,976
		R-7	$	11,962
BIE		W-7	$	5,359
BLE		M-7	$	8,244
		T-7	$	11,339
		W-7	$	11,356
		R-7	$	11,183
MFL		A	$	3,601
		B	$	2,481
		C	$	1,628
		D	$	3,335
		E	$	4,744
MVF		A	$	3,960
		B	$	3,366
		C	$	2,860
		D	$	693
		E	$	1,040
		F	$	13,949

58 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

Officers and Trustees

Richard E. Cavanagh, Chairman of the Board and Trustee
Karen P. Robards, Vice Chair of the Board, Chair of the Audit Committee and Trustee
G. Nicholas Beckwith, III, Trustee
Richard S. Davis, Trust President¹ and Trustee
Frank J. Fabozzi, Trustee and Member of the Audit Committee
Kathleen F. Feldstein, Trustee
James T. Flynn, Trustee and Member of the Audit Committee
Henry Gabbay, Trustee
Jerrold B. Harris, Trustee
R. Glenn Hubbard, Trustee
W. Carl Kester, Trustee and Member of the Audit Committee
Anne Ackerley, Trust President² and Chief Executive Officer
Brendan Kyne, Vice President
Neal Andrews, Chief Financial Officer
Jay Fife, Treasurer
Brian Kindelan, Chief Compliance Officer of the Trusts
Howard Surloff, Secretary

1	Trust President for MFL.
2	Trust President for all Trusts except MFL.

Investment Advisor

BlackRock Advisors, LLC

Wilmington, DE 19809

Sub-Advisors

BlackRock Investment Management, LLC¹

Plainsboro, NJ 08536

BlackRock Financial Management, Inc.²

New York, NY 10055

Custodians

The Bank of New York Mellon¹

New York, NY 10286

State Street Bank and Trust Company²

Boston, MA 02111

Transfer Agents

Common Shares:

BNY Mellon Shareowner Services¹

Jersey City, NJ 07310

Computershare Trust Company, N.A.²

Providence, RI 02940

Auction Agents

Preferred Shares:

The Bank of New York Mellon

New York, NY 10286

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

Address of the Trusts

100 Bellevue Parkway

Wilmington, DE 19809

1	For MFL and MVF.
2	For BYM, BAF, BBK, BIE and BLE.

Effective January 1, 2010, Kent Dixon, a Trustee of the Trusts, retired.

Effective March 31, 2010, G. Nicholas Beckwith, III, a Trustee of the Trusts, resigned.

The Trusts’ Board of Trustees wishes both Mr. Dixon and Mr. Beckwith well.

SEMI-ANNUAL REPORT FEBRUARY 28, 2010 59

Additional Information

Dividend Policy

The Trusts’ 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 Trusts 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 Trusts for any particular month may be more or less than the amount of net investment income earned by the Trusts during such month. The Trusts’ 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.

60 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

Additional Information (continued)

General Information

Electronic Delivery

Electronic copies of most financial reports are available on the Trusts’ web-sites or shareholders can sign up for e-mail notifications of quarterly statements, annual and semi-annual reports by enrolling in the Trusts’ electronic delivery program.

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

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

Householding

The Trusts 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 is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call (800) 441-7762.

Availability of Quarterly Schedule of Investments

Each Trust files its complete schedule of portfolio holdings with the Securities and Exchange Commission (“SEC”) for the first and third quarters of each fiscal year on Form N-Q. The Trusts’ 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 (202) 551-8090. Each Trust’s Forms N-Q may also be obtained upon request and without charge by calling (800) 441-7762.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the Trusts use to determine how to vote proxies relating to portfolio securities is available (1) without charge, upon request, by calling (800) 441-7762; (2) at www.blackrock.com; and (3) on the SEC’s website at http://www.sec.gov.

Availability of Proxy Voting Record

Information about how the Trusts voted proxies relating to securities held in the Trusts’ portfolios 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 SEC’s website at http://www.sec.gov.

SEMI-ANNUAL REPORT FEBRUARY 28, 2010 61

Additional Information (concluded)

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 information 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 applications, forms or other documents; (ii) information about your transactions 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 information. 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.

62 SEMI-ANNUAL REPORT FEBRUARY 28, 2010

This report is transmitted to shareholders only. It is not a prospectus. Past performance results shown in this report should not be considered a representation of future performance. The Trusts have leveraged their Common Shares, which creates risks for Common Shareholders, including the likelihood 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 reduce the Common Shares’ yield. Statements and other information herein are as dated and are subject to change.
	#CEF-NTL-7-2/10

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 second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.
Item 12 –	Exhibits attached hereto
12(a)(1) –	Code of Ethics – 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 MuniHoldings Insured Investment Fund
	By:	/s/ Anne F. Ackerley
		Anne F. Ackerley
		Chief Executive Officer of
		BlackRock MuniHoldings Insured Investment Fund
	Date: April 28, 2010
	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/ Anne F. Ackerley
		Anne F. Ackerley
		Chief Executive Officer (principal executive officer) of
		BlackRock MuniHoldings Insured Investment Fund
	Date: April 28, 2010
	By:	/s/ Neal J. Andrews
		Neal J. Andrews
		Chief Financial Officer (principal financial officer) of
		BlackRock MuniHoldings Insured Investment Fund
	Date: April 28, 2010