HBIO Harvard Bioscience Inc

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 * Green James W	2. Issuer Name and Ticker or Trading Symbol HARVARD BIOSCIENCE INC [ HBIO ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director                    _____ 10% Owner __X__ Officer (give title below)    _____ Other (specify below) Chief Executive Officer
(Last)          (First)          (Middle) C/O HARVARD BIOSCIENCE, INC., 84 OCTOBER HILL ROAD	3. Date of Earliest Transaction (MM/DD/YYYY) 5/21/2021
(Street) HOLLISTON, MA 01746 (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	5/21/2021		M		24312	A	$2.63	2304090 (1)	D
Common Stock	5/21/2021		S		24312	D	$7.14 (2)	2279778 (3)	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
Stock option (right to buy)	$2.63	5/21/2021		M			24312	(4)	6/11/2027	Common Stock	24312	$0	352690	D

Explanation of Responses:
(1)	Includes (a) an award of 194,698 restricted stock units that will vest in three equal installments on December 31, 2021, 2022 and 2023, subject to the terms set forth in an award agreement between the Issuer and the Reporting Person, (b) 163,606 remaining restricted stock units that will vest on December 31, 2021, 2022 and 2023, (c) 243,072 restricted stock units that will fully vest on July 8, 2021, (d) 209,180 remaining restricted stock units that will vest on January 1, 2022 and 2023, (e) 823,176 restricted stock units with performance based vesting conditions tied to relative total shareholder return, and (f) 670,358 shares of common stock beneficially owned by the Reporting Person.
(2)	This transaction was executed in multiple trades at prices ranging from $7.04 to $7.20, inclusive. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transaction was effected.
(3)	Includes (a) the shares and awards described in footnote (1) above, less (b) the disposition of shares reported in footnote (2) above.
(4)	The options vest in four equal installments on December 31, 2020, 2021, 2022 and 2023.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Green James W C/O HARVARD BIOSCIENCE, INC. 84 OCTOBER HILL ROAD HOLLISTON, MA 01746	X		Chief Executive Officer

Signatures
/s/ David Sirois, by power of attorney		5/25/2021
**Signature of Reporting Person		Date