INTERNAL CONTROL RPT

REPORT OF INDEPENDENT REGISTERED PUBLIC
ACCOUNTING FIRM

To the Shareholders and Board of Trustees/Directors of
BlackRock Municipal Bond Trust, BlackRock Municipal
Income Investment Quality Trust, BlackRock Municipal
Income Quality Trust, BlackRock Municipal Income Trust
II, BlackRock MuniHoldings Investment Quality Fund, and
BlackRock MuniVest Fund, Inc.:

In planning and performing our audits of the financial
statements of BlackRock Municipal Bond Trust, BlackRock
Municipal Income Investment Quality Trust, BlackRock
Municipal Income Quality Trust, BlackRock Municipal Income
Trust II, BlackRock MuniHoldings Investment Quality Fund,
and BlackRock MuniVest Fund, Inc. (the "Funds"), as of and
for the year ended August 31, 2019, in accordance with the
standards of the Public Company Accounting Oversight Board
(United States) (PCAOB), we considered the Funds' internal
control over financial reporting, including controls over
safeguarding securities, as a basis for designing our auditing
procedures for the purpose of expressing our opinion on the
financial statements and to comply with the requirements of
Form N-CEN, but not for the purpose of expressing an opinion
on the effectiveness of the Funds' internal control over
financial reporting. Accordingly, we express no such opinion.

The management of the Funds is responsible for establishing
and maintaining effective internal control over financial
reporting. In fulfilling this responsibility, estimates and
judgments by management are required to assess the expected
benefits and related costs of controls. A company's internal
control over financial reporting is a process designed to provide
reasonable assurance regarding the reliability of financial
reporting and the preparation of financial statements for
external purposes in accordance with generally accepted
accounting principles. A company's internal control over
financial reporting includes those policies and procedures that
(1) pertain to the maintenance of records that, in reasonable
detail, accurately and fairly reflect the transactions and
dispositions of the assets of the company; (2) provide
reasonable assurance that transactions are recorded as necessary
to permit preparation of financial statements in accordance with
generally accepted accounting principles, and that receipts and
expenditures of the company are being made only in
accordance with authorizations of management and directors of
the company; and (3) provide reasonable assurance regarding
prevention or timely detection of unauthorized acquisition, use,
or disposition of a company's assets that could have a material
effect on the financial statements.

Because of its inherent limitations, internal control over
financial reporting may not prevent or detect misstatements.
Also, projections of any evaluation of effectiveness to future
periods are subject to the risk that controls may become
inadequate because of changes in conditions or that the degree
of compliance with the policies or procedures may deteriorate.

A deficiency in internal control over financial reporting exists
when the design or operation of a control does not allow
management or employees, in the normal course of performing
their assigned functions, to prevent or detect misstatements on a
timely basis. A material weakness is a deficiency, or a
combination of deficiencies, in internal control over financial
reporting, such that there is a reasonable possibility that a
material misstatement of the company's annual or interim
financial statements will not be prevented or detected on a
timely basis.

Our consideration of the Funds' internal control over financial
reporting was for the limited purpose described in the first
paragraph and would not necessarily disclose all deficiencies in
internal control that might be material weaknesses under
standards established by the PCAOB. However, we noted no
deficiencies in the Funds' internal control over financial
reporting and its operation, including controls for safeguarding
securities, that we consider to be a material weakness, as
defined above, as of August 31, 2019.

This report is intended solely for the information and use of
management and the Board of Trustees/Directors of the Funds
and the Securities and Exchange Commission and is not
intended to be and should not be used by anyone other than
these specified parties.

/s/ Deloitte & Touche LLP
Boston, Massachusetts
October 22, 2019

MATERIAL AMENDMENTS

 

BLACKROCK MUNICIPAL BOND TRUST

AMENDMENT TO
STATEMENT OF PREFERENCES OF
VARIABLE RATE MUNI TERM PREFERRED SHARES
(“VMTP PREFERRED SHARES”)
DATED DECEMBER 15, 2011
(THE “STATEMENT OF PREFERENCES”)

The undersigned officer of BlackRock Municipal Bond Trust (the “Trust”), a Delaware statutory trust, hereby certifies as follows:

1.The Board of Trustees of the Trust (with the consent of the Holders (as defined in the Statement of Preferences) of the VMTP Preferred Shares required under Section 5 of the Statement of Preferences) has adopted resolutions to amend the Statement of Preferences as follows as of January 2, 2019:

(a)The section titled “Designation” in the Statement of Preferences is hereby deleted and replaced in its entirety with the following:

Series W-7: A series of 799 preferred shares of beneficial interest in the Trust, par value $0.001 per share, liquidation preference $100,000 per share, is hereby authorized and designated “Series W-7 VMTP Preferred Shares”. Each Series W-7 VMTP Preferred Share shall be issued on a date or dates determined by the Board of Trustees of the Trust or pursuant to their delegated authority; have an Applicable Rate commencing on January 3, 2019 equal to the sum of 0.79% per annum plus 75% of the one-month LIBOR Rate (as defined herein); and have such other preferences, voting powers, restrictions, limitations as to dividends and distributions, qualifications and terms and conditions of redemption, required by Applicable Law and that are expressly set forth in this Statement of Preferences and the Declaration of Trust. The Series W-7 VMTP Preferred Shares shall constitute a separate series of preferred shares of beneficial interest in the Trust and each Series W-7 VMTP Preferred Share shall be identical. Except as otherwise provided with respect to any additional Series of VMTP Preferred Shares, the terms and conditions of this Statement of Preferences apply to each Series of VMTP Preferred Shares.

(b)The definitions of “SIFMA” and “SIFMA Municipal Swap Index” in the “Definitions” section of the Statement of Preferences are hereby deleted.

(c)The definition of “Applicable Base Rate” in the Definitions section of the Statement of Preferences is hereby deleted and replaced in its entirety with the following:

“Applicable Base Rate” means 75% of the one-month LIBOR Rate on the applicable Rate Determination Date.

(d)The definition of “Ratings Spread” in the Definitions section of the Statement of Preferences is hereby deleted and replaced in its entirety with the following:

31753614.1

“Ratings Spread” means, with respect to any Rate Period for any Series of VMTP Preferred Shares, the percentage per annum set forth opposite the highest applicable credit rating assigned to such Series, unless the lowest applicable rating is at or below A1/A+, in which case it shall mean the percentage per annum set forth opposite the lowest applicable credit rating assigned to such Series, by either Moody’s (if Moody’s is then rating the VMTP Preferred Shares at the request of the Trust), Fitch (if Fitch is then rating the VMTP Preferred Shares at the request of the Trust) or Other Rating Agency (if such Other Rating Agency is then rating the VMTP Preferred Shares at the request of the Trust) in the table below on the Rate Determination Date for such Rate Period:

Moody’s/Fitch*	Proposed Percentage
Aa2/AA to Aaa/AAA	0.79%
Aa3/AA-	0.95%
A1/A+	1.30%
A2/A	1.55%
A3/A-	1.70%
Baa1/BBB+	2.05%
Baa2/BBB	2.30%
Baa3/BBB-	2.80%
Non-investment grade or NR	3.30%

*And/or the equivalent ratings of an Other Rating Agency then rating the VMTP Preferred Shares at the request of the Trust.

(e)The definition of “LIBOR Rate” in the Definitions section of the Statement of Preferences is hereby deleted and replaced in its entirety with the following:

“LIBOR Rate” means, on any Rate Determination Date, (i) the one-month LIBOR rate for deposits in United States dollars, which appears on Reuters display page LIBOR01 (“Page LIBOR01”) (or such other page as may replace that page on that service, or such other service as may be selected by the LIBOR Dealer or its successors that are LIBOR Dealers) as of 11:00 a.m. London, England time, on the day that is the London Business Day preceding the Rate Determination Date (the “LIBOR Determination Date”), or (ii) if such rate does not appear on Page LIBOR01 or such other page as may replace such Page LIBOR01, (A) the LIBOR Dealer shall determine the arithmetic mean of the offered quotations of the Reference Banks to leading banks in the London interbank market for deposits in U.S. dollars for the designated Rate Period in an amount determined by such LIBOR Dealer by reference to requests for quotations as of approximately 11:00 a.m. (London, England time) on such date made by such LIBOR Dealer to the Reference Banks, (B) if at least two of the Reference Banks provide such quotations, the LIBOR Rate shall equal such arithmetic mean of such quotations, (C) if only one or none of the Reference Banks provide such quotations, the LIBOR Rate shall be deemed to be the arithmetic mean of the offered quotations that leading banks in The City of New York, New York selected by the LIBOR Dealer (after obtaining the Trust’s approval) are quoting on the relevant LIBOR Determination Date for deposits in United States dollars for the designated Rate Period in an amount determined by the LIBOR Dealer (after obtaining the Trust’s approval) that is representative of a single transaction in such market at such time by reference to the principal London, England offices of leading banks in the London interbank market; provided, however, that if one of the LIBOR Dealers does not quote a rate required to determine the LIBOR Rate, the LIBOR Rate will be determined on the basis of the quotation or quotations furnished by any Substitute LIBOR Dealer or Substitute LIBOR Dealers selected by the Trust to provide such rate or rates not being supplied by the LIBOR Dealer. Notwithstanding the foregoing, if (A) the one month LIBOR Rate determined as set forth above would otherwise be less than zero (0), the one-month LIBOR Rate for such Rate Determination Date will be deemed to be zero (0), and (B) the one-month LIBOR Rate no longer appears or is not otherwise calculable as provided above (the “LIBOR Unavailability Date”), then the one-month LIBOR Rate shall mean (i) the “Federal Funds Rate,” which appears on Bloomberg display page FEDL01 (“Page FEDL01”) (or such other page as may replace that page on that service, or such other service as may be selected by the LIBOR Dealer or its successors that are LIBOR Dealers) as of 5:00 p.m. New York City time plus the positive difference, if any, between the average one-month LIBOR Rate and the average Federal Funds Rate for the one year period prior to the LIBOR Unavailability Date, or (ii) if such rate does not appear on Page FEDL01 or such other page as may replace such Page FEDL01 (the date on which such rate no longer appears on such page, the “Fed Funds Unavailability Date”), the Board of Trustees shall in good faith select a reasonably comparable index, which such other index shall be subject to the prior written consent of the Total Holders (the “Replacement”). If applicable, the one-month LIBOR Rate from the latter of (i) the LIBOR Unavailability Date and (ii) the Fed Funds Unavailability Date to the date the Replacement becomes effective with the prior written consent of the Total Holders as provided above, shall be equal to the one-month LIBOR Rate as in effect immediately prior to the latter of (i) the LIBOR Unavailability Date and (ii) the Fed Funds Unavailability Date.

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31753614.1

(f)The definition of “Overconcentration Amount” in the Definitions Section of the Statement of Preferences is hereby deleted and replaced in its entirety with the following:

“Overconcentration Amount” means as of any date of calculation of the Effective Leverage Ratio, an amount equal to the sum of: (i) the Market Value of the Trust’s assets in a single state or territory in excess of 20%; (ii) the Market Value of the Trust’s assets in a single state or territory rated lower than A2 by Moody’s or A by S&P or Fitch in excess of 15%; (iii) the Market Value of the Trust’s assets in a single state or territory rated lower than Baa3 by Moody’s or BBB- by S&P or Fitch in excess of 10%; (iv) the Market Value of the Trust’s assets that constitute tobacco obligations (excluding tobacco obligations that are Defeased Securities and tobacco obligations backed by state appropriation) in excess of 10%; (v) the Market Value of the Trust’s assets paying less frequently than semi-annually in excess of 20%; (vi) the Market Value of the Trust’s assets that constitute tobacco obligations backed by state appropriation in excess of 10%; in each case, as a percentage of the Market Value of the Trust’s Managed Assets and (vii) the Market Value of the Trust’s Deferred Compensation Hedge Assets and Deferred Compensation Plan Assets in excess of 0%.

2.Except as amended hereby, the Statement of Preferences remains in full force and effect.

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31753614.1

3.An original copy of this amendment shall be lodged with the records of the Trust and filed in such places as the Trustees deem appropriate.

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31753614.1

IN WITNESS WHEREOF, BlackRock Municipal Bond Trust has caused these presents to be signed as of December 28, 2018 in its name and on its behalf by its Vice President and attested by its Secretary. Said officers of the Trust have executed this amendment as officers and not individually, and the obligations and rights set forth in this amendment are not binding upon any such officers, or the trustees or shareholders of the Trust, individually, but are binding only upon the assets and property of the Trust.

BLACKROCK MUNICIPAL BOND TRUST

By:   /s/ Jonathan Diorio                                      

Name:   Jonathan Diorio

Title:     Vice President

ATTEST:

/s/ Janey Ahn                                                     
Name:   Janey Ahn

Title:     Secretary

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