Quanterix (NASDAQ: QTRX) — Ameriprise reports 3,542,374 shared votes

Rhea-AI Filing Summary

Ameriprise Financial, Inc. filed Amendment No. 5 to a Schedule 13G/A reporting shared voting and dispositive power over 3,542,374 shares of Quanterix Corp common stock (CUSIP 74766Q101), representing 7.5% of the class. The filing states that AFI disclaims beneficial ownership of the shares reported and incorporates the cover‑page rows by reference.

Insights

Institutional Ownership Analyst

Ameriprise reports a meaningful passive stake with shared control rights.

Ameriprise discloses shared voting and shared dispositive power over 3,542,374 shares, equal to 7.5% of Quanterix common stock. The schedule is an amendment (No. 5) to prior 13G filings and updates the reporting cover‑page rows.

Because AFI disclaims beneficial ownership, this filing signals institutional involvement via shared authority rather than an explicit ownership claim; subsequent filings would show any changes in position or voting arrangements.

Securities Compliance Counsel

Filing is a routine Section 13 disclosure updating power/percent data and preserving compliance.

The Schedule 13G/A format and signature by an authorized officer meet disclosure obligations: name, address, CUSIP 74766Q101, and the reported rows for voting/dispositive power are incorporated by reference. The signature block is signed by Michael G. Clarke.

Qualifiers such as the disclaimer of beneficial ownership are material to legal attribution; the document preserves the reporting record without asserting direct beneficial ownership.

Key Figures

Reported shared voting power: 3,542,374 shares Reported shared dispositive power: 3,542,374 shares Percent of class: 7.5% +1 more

4 metrics

Reported shared voting power 3,542,374 shares cover‑page rows incorporated in Schedule 13G/A

Reported shared dispositive power 3,542,374 shares cover‑page rows incorporated in Schedule 13G/A

Percent of class 7.5% reported on the Schedule 13G/A cover page

CUSIP 74766Q101 Quanterix Corp common stock identifier on the filing

Key Terms

Schedule 13G/A, shared dispositive power, disclaims beneficial ownership

3 terms

Schedule 13G/A regulatory

"Amendment No. 5 to a Schedule 13G/A reporting beneficial ownership"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

shared dispositive power regulatory

"Shared Dispositive Power 3,542,374.00"

disclaims beneficial ownership regulatory

"AFI disclaims beneficial ownership of any shares reported on this Schedule"

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Accepted by SEC EDGAR 05/15/2026 - 10:36 AM Learn about SEC filing dates

FAQ

What stake does Ameriprise Financial report in Quanterix (QTRX)?

Ameriprise reports shared voting and dispositive power over 3,542,374 shares, representing 7.5% of Quanterix common stock. The figure is taken from the cover‑page rows incorporated into the Schedule 13G/A amendment.

Does Ameriprise claim beneficial ownership of the reported Quanterix shares?

No. The filing explicitly states that Ameriprise disclaims beneficial ownership of the shares reported on this Schedule, while still reporting shared voting and dispositive powers in the cover rows.

Which document and amendment reports this disclosure for QTRX?

The disclosure appears on a Schedule 13G/A (Amendment No. 5) filed by Ameriprise Financial, Inc., which incorporates the cover‑page rows (voting, dispositive power, percent) by reference.

Who signed the Schedule 13G/A amendment for Ameriprise?

The filing is signed by /s/ Michael G. Clarke, Senior Vice President, North America Head of Operations & Investor Services, with contact details for Charles Chiesa, VP Fund Treasurer.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 5)

Quanterix Corp

(Name of Issuer)

Common Stock

(Title of Class of Securities)

74766Q101

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 74766Q101

1

Names of Reporting Persons

Ameriprise Financial, Inc.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 3,542,374.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,542,374.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,542,374.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

7.5 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Quanterix Corp
(b)	Address of issuer's principal executive offices: 900 Middlesex Turnpike, Billerica, MA 01821
Item 2.
(a)	Name of person filing: Ameriprise Financial, Inc. ("AFI")
(b)	Address or principal business office or, if none, residence: 145 Ameriprise Financial Center, Minneapolis, MN 55474
(c)	Citizenship: Delaware
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 74766Q101
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: Incorporated by reference to Items (5)-(9) and (11) of the cover page pertaining to the reporting person. AFI disclaims beneficial ownership of any shares reported on this Schedule.
(b)	Percent of class: The information required by Item 4(b) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: The information required by Item 4(c) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person.
	(ii) Shared power to vote or to direct the vote: The information required by Item 4(c) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person.
	(iii) Sole power to dispose or to direct the disposition of: The information required by Item 4(c) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person.
	(iv) Shared power to dispose or to direct the disposition of: The information required by Item 4(c) is set forth in Rows (5)-(9) and (11) of the cover page for the Reporting Person hereto and is incorporated herein by reference for the Reporting Person.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Ameriprise Financial, Inc.

Signature:	/s/ Michael G. Clarke
Name/Title:	Michael G. Clarke, Senior Vice President, North America Head of Operations & Investor Services
Date:	05/15/2026

Comments accompanying signature: Contact Information Charles Chiesa VP Fund Treasurer Global Operations and Investor Services Telephone: 617-385-9593