[Form 4] Quanterix Corp Insider Trading Activity

Rhea-AI Filing Summary

Quanterix Corporation (QTRX)70,091 shares of Quanterix common stock at an exercise price of $5.91 per share. These options expire on 11/20/2035.

The options vest monthly over two years in 24 equal installments, as long as the Executive Chair continues providing service to Quanterix on each vesting date. Following this transaction, the reporting person beneficially owns 70,091 derivative securities directly.

11/24/2025 - 07:07 PM

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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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^*

DONNELLY WILLIAM P

(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
X	Officer (give title below)		Other (specify below)
	Executive Chair

3. Date of Earliest Transaction (Month/Day/Year)
11/20/2025

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

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
Stock Options (Right to buy)	$5.91	11/20/2025		A		70,091		(1)	11/20/2035	Common Stock	70,091	$0.00	70,091	D

Explanation of Responses:

1. The stock options vest monthly over two years in 24 equal installments, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

Remarks:

	/s/ Bonnie McManus, as Attorney-in-Fact	11/24/2025
	** 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) disclose in this Form 4 filing?

Quanterix disclosed that its Executive Chair and Director received stock options on 11/20/2025 to purchase 70,091 shares of common stock at an exercise price of $5.91 per share, expiring on 11/20/2035.

Who is the reporting person in the Quanterix (QTRX) Form 4 filing?

The reporting person is a Director and Officer of Quanterix, serving as Executive Chair, and files the form as a single reporting person.

What are the key terms of the Quanterix (QTRX) stock options granted?

The derivative security is a stock option (right to buy) with an exercise price of $5.91 per share, covering 70,091 shares of Quanterix common stock and expiring on 11/20/2035.

How do the Quanterix (QTRX) stock options vest for the Executive Chair?

The stock options vest monthly over two years in 24 equal installments, subject to the Executive Chair continuing to provide service to Quanterix on each vesting date.

How many derivative securities does the Quanterix (QTRX) insider own after this transaction?

After the reported transaction, the insider beneficially owns 70,091 derivative securities directly, representing the stock options described.

Is this Quanterix (QTRX) Form 4 filing about non-derivative or derivative securities?

This filing reports derivative securities, specifically stock options to buy Quanterix common stock, listed in Table II of the form.