[Form 4] Quanterix Corp Insider Trading Activity

Rhea-AI Filing Summary

Quanterix Corporation director Walt David R received 2,594 shares of common stock on 10/01/2025 as compensation in lieu of cash for third‑quarter 2025 board and committee fees, at the Nasdaq closing price of $5.54 per share. After the grant, the reporting person beneficially owns 1,871,675 shares, which include 7,435 restricted stock units. The Form 4 was signed by an attorney‑in‑fact on 10/03/2025. The filing discloses a single non‑derivative acquisition and explains the grant source and price; no options, dispositions, or additional derivative transactions are reported.

Positive

• Director accepted 2,594 shares in lieu of cash, increasing alignment with shareholders
• Total beneficial ownership of 1,871,675 shares disclosed, providing transparency

Negative

• None.

Insights

Corporate Governance Expert

Director received equity in lieu of cash, increasing insider stake.

Receiving 2,594 shares as board compensation converts cash costs to equity, aligning the director's interests with shareholders by increasing ownership without a cash payout.

The filing shows total beneficial ownership of 1,871,675 shares, including 7,435 RSUs, which is a concrete disclosure of insider exposure to company performance. This Form 4 contains no sales or derivative activity that would indicate immediate liquidity events.

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
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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^*

WALT DAVID R

(Last) (First) (Middle)

C/O QUANTERIX CORPORATION,

900 MIDDLESEX TURNPIKE

(Street)

BILLERICA MA 01821

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Quanterix Corp [ QTRX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
10/01/2025

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

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. 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	10/01/2025		A		2,594(1)	A	$5.54(2)	1,871,675(3)	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. Consists of stock granted in lieu of cash fees for service on the Company's Board of Directors and committees thereof for the third quarter of 2025.

2. Closing price of the Company's common stock on the Nasdaq Global Market on October 1, 2025.

3. Includes 7,435 restricted stock units.

Remarks:

	/s/ Brian Keane, as Attorney-in-Fact	10/03/2025
	** 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.

FAQ

What did Quanterix (QTRX) director Walt David R receive on 10/01/2025?

He received 2,594 shares of common stock as compensation in lieu of cash for Q3 2025 board and committee service.

At what price were the shares recorded on the Form 4 for QTRX?

The shares were recorded at the Nasdaq closing price of $5.54 per share on 10/01/2025.

How many shares does the reporting person beneficially own after the transaction?

The Form 4 reports beneficial ownership of 1,871,675 shares, which includes 7,435 restricted stock units.

Does the Form 4 report any sales or derivative transactions by the reporting person?

No. The filing reports a single non‑derivative acquisition and no dispositions or derivative transactions.

Who signed the Form 4 and when was it signed?

The Form 4 was signed by Brian Keane, as Attorney‑in‑Fact on 10/03/2025.