William P. Donnelly - 12 Aug 2026 Form 4 Insider Report for Quanterix Corp (QTRX)

Reporting relationship: Director
Issuer ticker: QTRX
Reported as of: 12 Aug 2026
Net transaction value: +$286,354
SEC form: 4
Accepted by SEC: 14 Aug 2026, 16:01:41 UTC
Prior SEC filing: 02 Jul 2026
Next SEC filing: 19 Aug 2026
Source filing: View source filing
Reporting owner signature: /s/ Meghan Shevlin, Attorney-in-Fact

Key filing fact

William P. Donnelly filed Form 4 for Quanterix Corp (QTRX) on 14 Aug 2026.

Key facts

This page summarizes William P. Donnelly's Form 4 filing for Quanterix Corp (QTRX).
2 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 14 Aug 2026, 16:01.

Change

Previous filing in this sequence was filed on 02 Jul 2026.
Current net transaction value: +$286,354.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001207928 Primary reporting owner

DONNELLY WILLIAM P

Relationship: Director
Address: C/O QUANTERIX CORPORATION, 900 MIDDLESEX TURNPIKE, BILLERICA
Signature: /s/ Meghan Shevlin, Attorney-in-Fact
Signature date: 14 Aug 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

QTRX transaction

Common Stock

Purchase

Transaction value: $74,676
Shares: +27,155
Change %
Price: $2.75
Shares after: 27,155
Date: 12 Aug 2026
Ownership: See footnote
Footnotes: F1, F2

QTRX transaction

Common Stock

Purchase

Transaction value: $211,678
Shares: +72,245
Change %: +266%
Price: $2.93
Shares after: 99,400
Date: 13 Aug 2026
Ownership: See Footnote
Footnotes: F2, F3

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 3 footnotes

Footnote F1

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.58 to $2.95, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote.

Footnote F2

Owned jointly by trusts established by the reporting person and his spouse.

Footnote F3

The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.85 to $3.13, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote.