Harvard Bioscience (HBIO) director buys 10,000 shares in open market

Rhea-AI Filing Summary

Harvard Bioscience director Stephen J. Denelsky bought 10,000 shares of common stock in an open-market transaction at $4.87 per share. After this purchase on March 17, 2026, he directly holds 21,000 shares, including 11,000 restricted stock units scheduled to fully vest on September 5, 2026.

The footnotes also note that on March 13, 2026, Harvard Bioscience completed a 10-for-1 reverse stock split, and the 11,000 restricted stock units were adjusted from a previously reported 110,000 units to reflect this split.

Insider Trade Summary

Net Buyer: 10,000 shares ($48,700)

Net Buy 1 txn

Insider DENELSKY STEPHEN J

Role Director

Bought 10,000 shs ($49K)

Type	Security	Shares	Price	Value
Purchase	Common Stock	10,000	$4.87	$49K

Holdings After Transaction: Common Stock — 21,000 shares (Direct)

Footnotes (1)

1. Includes (a) 10,000 shares of common stock purchased on March 17, 2026 and (b) 11,000 restricted stock units that fully vest on September 5, 2026. On March 13, 2026, the common stock of Harvard Bioscience, Inc. underwent a reverse stock split in a ratio of 10-for-1. The 11,000 restricted stock units referenced in Footnote 1(b) were previously reported as covering 110,000 restricted stock units. These numbers have been adjusted to reflect the stock split that occurred on March 13, 2026.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

DENELSKY STEPHEN J

(Last) (First) (Middle)

C/O HARVARD BIOSCIENCE, INC.

84 OCTOBER HILL ROAD

(Street)

HOLLISTON MASSACHUSETTS 01746

(City) (State) (Zip)

UNITED STATES

(Country)

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
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/17/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction 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	03/17/2026		P		10,000	A	$4.87	21,000(1)(2)	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction 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 (Month/Day/Year)		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: 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. Includes (a) 10,000 shares of common stock purchased on March 17, 2026 and (b) 11,000 restricted stock units that fully vest on September 5, 2026.

2. On March 13, 2026, the common stock of Harvard Bioscience, Inc. underwent a reverse stock split in a ratio of 10-for-1. The 11,000 restricted stock units referenced in Footnote 1(b) were previously reported as covering 110,000 restricted stock units. These numbers have been adjusted to reflect the stock split that occurred on March 13, 2026.

	/s/ Stephen DeNelsky	03/18/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Harvard Bioscience (HBIO) report on this Form 4?

Harvard Bioscience reported that director Stephen J. Denelsky bought 10,000 shares of common stock in an open-market purchase at $4.87 per share. The transaction occurred on March 17, 2026, and increased his directly held position in the company.

How many Harvard Bioscience (HBIO) shares does the director hold after this trade?

After the March 17, 2026 purchase, Stephen J. Denelsky holds 21,000 shares directly. This figure includes 11,000 restricted stock units that are scheduled to fully vest on September 5, 2026, according to the Form 4 footnote disclosure.

At what price did the Harvard Bioscience (HBIO) director buy shares?

Stephen J. Denelsky bought 10,000 Harvard Bioscience common shares at $4.87 per share in an open-market transaction. This price reflects what he paid per share on March 17, 2026, as disclosed in the Form 4 filing.

What does the restricted stock unit vesting mean for Harvard Bioscience (HBIO) director holdings?

The director’s total 21,000-share holding includes 11,000 restricted stock units that fully vest on September 5, 2026. Once these units vest, they convert into common shares, increasing his freely usable equity stake, subject to any applicable company or regulatory restrictions.

How did Harvard Bioscience’s recent reverse stock split affect reported restricted stock units?

Harvard Bioscience completed a 10-for-1 reverse stock split on March 13, 2026. As a result, the director’s restricted stock units were adjusted from 110,000 previously reported units to 11,000 units, aligning the equity awards with the new post-split share count.

Is this Harvard Bioscience (HBIO) insider transaction a purchase or a sale?

This Form 4 reflects an open-market purchase by director Stephen J. Denelsky, not a sale. He acquired 10,000 shares of Harvard Bioscience common stock, increasing his overall direct holdings as disclosed in the filing data.