William P. Donnelly - 20 Nov 2025 Form 4 Insider Report for Quanterix Corp (QTRX)

Role: Executive Chair, Director
Signature: /s/ Bonnie McManus, as Attorney-in-Fact
Issuer symbol: QTRX
Transactions as of: 20 Nov 2025
Net transactions value: $0
Form type: 4
Filing time: 24 Nov 2025, 19:07:14 UTC
Previous filing: 03 Oct 2025
Next filing: 02 Jan 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
DONNELLY WILLIAM P	Executive Chair, Director	C/O QUANTERIX CORPORATION, 900 MIDDLESEX TURNPIKE, BILLERICA	/s/ Bonnie McManus, as Attorney-in-Fact	24 Nov 2025	0001207928

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	QTRX	Stock Options (Right to buy)	Award	$0	+70,091		$0.000000	70,091	20 Nov 2025	Common Stock	70,091	$5.91	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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.