As of November 10, 2026, Quanterix Corp is a publicly traded company (Nasdaq: QTRX); its largest reported holder is Ameriprise, with 7.5% on Schedule 13G/A of May 15, 2026, then BlackRock (7.3%). The largest insider holding is David R. Walt, a director, with 1,872,890 shares (3.9% of shares outstanding), per Form 4 of January 6, 2026 (Schedule 13G/A, May 15, 2026).
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Is Quanterix Corp a real, registered company?
- Quanterix Corp files with the SEC under CIK 1503274 (its SEC filings).
- Its shares are listed under the ticker QTRX on Nasdaq (SEC company record).
- Incorporated in Delaware; business address in Billerica, Massachusetts, as its SEC filings state.
- Court and bankruptcy records: see Before you sign or pay below.
Before you sign or pay
- Court and bankruptcy: No federal court case or bankruptcy filing found under Quanterix Corp in our court records and SEC 8-K records (as of 2026-11-10).
- Leadership changes: the latest reported is Jason Faessler, Chief Financial Officer (Form 8-K filed 2026-06-09). Check you are dealing with the people now in charge.
- Ownership: 5%+ holders are reported on Schedule 13D or 13G; the latest names First Eagle Investment Management, LLC (filed 2026-08-06).
Who are Quanterix Corp's owners and officers?
Quanterix Corp: incorporated in Delaware; business address in Billerica, Massachusetts; industry Laboratory Analytical Instruments (Schedule 13G/A, 2026-08-14).
| Report | Holder | Share |
|---|---|---|
| Schedule 13G/A, 2026-08-14 | Portolan Capital Management, LLC | 4.02% |
| Schedule 13G, 2026-08-06 | First Eagle Investment Management, LLC | 5.8% |
| Schedule 13G/A, 2026-05-15 | Portolan Capital Management, LLC | 6.25% |
| Schedule 13G/A, 2026-05-15 | Ameriprise Financial, Inc. | 7.5% |
| Schedule 13G/A, 2026-05-07 | Ameriprise Financial, Inc. | 2.1% |
| Schedule 13G/A, 2026-03-27 | The Vanguard Group | 0% |
| Schedule 13G/A, 2026-02-17 | Ameriprise Financial, Inc. | 10.7% |
| Schedule 13G, 2025-11-19 | Telegraph Hill Partners Iii, L.P. | 5.4% |
| Schedule 13G/A, 2025-11-14 | Ameriprise Financial, Inc. | 9.1% |
| Schedule 13G/A, 2025-08-13 | Portolan Capital Management, LLC | 9.36% |
| Schedule 13G/A, 2025-07-17 | Blackrock, Inc. | 7.3% |
| Schedule 13D/A, 2025-07-15 | Kent Lake Pr LLC | 4.5% |
Questions about who owns Quanterix Corp
Who owns Quanterix Corp?
On this page, 4 holders' latest ownership filings report 5% or more of Quanterix Corp: Ameriprise Financial, Inc. (7.5%, Schedule 13G/A, filed 2026-05-15), Blackrock, Inc. (7.3%, Schedule 13G/A, filed 2025-07-17), First Eagle Investment Management, LLC (5.8%, Schedule 13G, filed 2026-08-06) and Telegraph Hill Partners Iii, L.P. (5.4%, Schedule 13G, filed 2025-11-19).
Who are the largest shareholders of Quanterix Corp?
By the share each holder's latest filing reports, the largest holders of Quanterix Corp on this page are Ameriprise Financial, Inc. (7.5%), Blackrock, Inc. (7.3%) and First Eagle Investment Management, LLC (5.8%).
When did Ameriprise Financial, Inc. buy into Quanterix Corp?
The filings give report dates, not purchase dates. The earliest filing from Ameriprise Financial, Inc. on this page is the Schedule 13G/A, filed 2025-11-14, reporting 9.1%; its latest, Schedule 13G/A filed 2026-05-15, reports 7.5%. That earliest filing is itself an amendment, which updates an earlier report.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 12 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
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| Filed | Person | Role | Change | Effective |
|---|---|---|---|---|
| Form 8-K, 2026-06-09 | Jason Faessler | Chief Financial Officer | appointed | |
| Form 8-K, 2026-05-26 | Anthony Catalano | Chief Operating Officer | appointed |
Which insiders own Quanterix Corp shares?
Directors, officers and holders of 10% or more report their shares on Forms 3, 4 and 5. Each line is the latest such report, largest holding first.
- , a director: 1,872,890 shares (3.9% of shares outstanding) (Form 4, 2026-01-06).
- , the chief executive and president: 507,310 shares (1.1% of shares outstanding) (Form 4, 2026-01-20).
- , a director: 313,253 shares (0.66% of shares outstanding) (Form 4, 2026-01-15).
- , a director: 291,541 shares (0.61% of shares outstanding), 36,908 held directly and 254,633 indirectly (Form 4, 2025-01-06).
- , a director: 169,365 shares (0.36% of shares outstanding) (Form 4, 2026-10-02).
Shares outstanding: 47,478,422 as of 2026-11-02, from the company's latest SEC cover page.
How much has Quanterix Corp raised?
No fundraising or offering filing from Quanterix Corp is on file with us.
Keep reading
More on Quanterix Corp and the records around it.
Quanterix Corp elsewhere on the record
- 5%+ stake filings Aug 2026
- Leadership changes Jun 2026
Companies that share a holder
- Kent Lake Partners LP also filed stake reports on 1 other company: UNIVERSAL ELECTRONICS INC (Nov 2025)
- Portolan Capital Management, LLC also filed stake reports on 13 other companies: LANTRONIX, INC. (Oct 2026), SILICOM LTD. (Sep 2026), Real Brokerage Inc (Aug 2026)
- First Eagle Investment Management, LLC also filed stake reports on 16 other companies: AMTECH SYSTEMS INC (Aug 2026), DENTSPLY SIRONA Inc. (Aug 2026), Warrior Met Coal Inc (Aug 2026)
Related pages
Filings, cases and notices link to their records. A not-found line names the records searched; it is not proof of absence.
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https://mentionfox.com/who-owns/quanterix