BBK BlackRock Municipal Bond Trust

FORM 4 [ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).         
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES                                                                                   
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940                       

1. Name and Address of Reporting Person * HUBBARD ROBERT GLENN	2. Issuer Name and Ticker or Trading Symbol BLACKROCK MUNICIPAL BOND TRUST [ BBK ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director                    _____ 10% Owner _____ Officer (give title below)    _____ Other (specify below)
(Last)          (First)          (Middle) 55 EAST 52ND STREET	3. Date of Earliest Transaction (MM/DD/YYYY) 3/8/2021
(Street) NEW YORK, NY 10055 (City)        (State)        (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. Code (Instr. 8)		4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	3/8/2021		J(1)		275.1	D	(1)	0	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

(1)

Effective as of March 8, 2021, BlackRock Municipal Bond Trust (the "Target Fund") was reorganized into BlackRock MuniHoldings Fund, Inc. (the "Acquiring Fund"). In the Reorganization, common shareholders of the Target Fund received common shares of the Acquiring Fund having a value equal to the aggregate NAV of the Target Fund common shares surrendered as determined at the close of business on March 5, 2021, less the costs of the Reorganization. As of March 5, 2021, the Target Fund reported a NAV per share of $16.4314 and the Acquiring Fund reported a NAV per share of $16.9927. The conversion ratio for the Target Fund's common shares was 0.96696817. In the Reorganization, R. Glenn Hubbard received 266 common shares (and cash for fractional shares, if any) of the Acquiring Fund in exchange for his 275.10 common shares of the Target Fund.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
HUBBARD ROBERT GLENN 55 EAST 52ND STREET NEW YORK, NY 10055	X

Signatures
/s/ Dean A. Caruvana as Attorney-in-Fact		3/10/2021
**Signature of Reporting Person		Date