SEC FORM 4 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
 
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checkbox unchecked Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
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1. Name and Address of Reporting Person*
Sachs Alan Bruce

(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)
checkbox checked Director 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
01/02/2026
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
checkbox checked 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
Common Stock 01/02/2026 A 23,372(1) A $0.00 70,099(2) D
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
Explanation of Responses:
1. Represents restricted stock units that vest as to 100% of the shares on January 2, 2027 granted pursuant to the Quanterix Corporation Amended and Restated Non-Employee Director Compensation Policy. Each restricted stock unit represents the right to receive one share of the Issuer's common stock.
2. Includes 70,099 restricted stock units.
Remarks:
/s/ Bonnie McManus, Attorney-in-Fact 01/06/2026
** 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.
LIMITED POWER OF ATTORNEY

The undersigned hereby constitutes and appoints Bonnie McManus of
Quanterix Corporation (the "Company") and David Engvall and William
Mastrianna of Covington & Burling LLP, and each of them, the
undersigned's true and lawful attorney-in-fact to:

execute for and on behalf of the undersigned, in the undersigned's
capacity as an officer and/or director of the Company, Forms 3, 4s and
5s in accordance with Section 16(a) of the Securities Exchange Act of
1934, as amended (the "Exchange Act"), and the rules and regulations
thereunder;

execute for and on behalf of the undersigned, in the undersigned's
capacity as an officer and/or director of the Company, Forms 3, 4s and
5s in accordance with Section 16(a) of the Securities Exchange Act of
1934, as amended (the "Exchange Act"), and the rules and regulations
thereunder;

do and perform any and all acts for and on behalf of the undersigned
that may be necessary or desirable to complete and execute any such
Forms 3, 4s and 5s and timely file such forms with the Securities and
Exchange Commission and any stock exchange or similar authority, if
required; and

do and perform any and all acts for and on behalf of the undersigned
that may be necessary or desirable to complete and execute any such
Forms 3, 4s and 5s and timely file such forms with the Securities and
Exchange Commission and any stock exchange or similar authority, if
required; and

take any other action of any type whatsoever in connection with the
foregoing that, in the opinion of such attorney-in-fact, may be of
benefit to, in the best interest of, or legally required by, the
undersigned, it being understood that the documents executed by such
attorney-in-fact on behalf of the undersigned pursuant to this Limited
Power of Attorney shall be in such form and shall contain such terms
and conditions as such attorney-in-fact may approve in such attorney-
in-fact's discretion.

take any other action of any type whatsoever in connection with the
foregoing that, in the opinion of such attorney-in-fact, may be of
benefit to, in the best interest of, or legally required by, the
undersigned, it being understood that the documents executed by such
attorney-in-fact on behalf of the undersigned pursuant to this Limited
Power of Attorney shall be in such form and shall contain such terms
and conditions as such attorney-in-fact may approve in such attorney-
in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact full power
and authority to do and perform each and every act and thing
whatsoever requisite, necessary or proper to be done in the exercise
of any of the rights and powers herein granted, as fully to all
intents and purposes as the undersigned might or could do if
personally present, with full power of substitution and revocation,
hereby ratifying and confirming all that each such attorney-in-fact,
or each such attorney-in-fact's substitute or substitutes, shall
lawfully do or cause to be done by virtue of this power of attorney
and the rights and powers herein granted.  The undersigned
acknowledges that each of the foregoing attorneys-in-fact, in serving
in such capacity at the request of the undersigned, is not assuming,
nor is the Company assuming, any of the undersigned's responsibilities
to comply with Section 16 of the Exchange Act.

The undersigned agrees that each such attorney-in-fact may rely
entirely on information furnished orally or in writing by the
undersigned to each such attorney-in-fact. The undersigned also agrees
to indemnify and hold harmless the Company and each such attorney-in-
fact against any losses, claims, damages or liabilities (or actions in
these respects) that arise out of or are based on any untrue statement
or omission of necessary facts in the information provided by the
undersigned to such attorney-in-fact for purposes of executing,
acknowledging, delivering and filing Forms 3, 4s or 5s (including
amendments thereto) and agrees to reimburse the Company and each such
attorney-in-fact for any legal or other expenses reasonably incurred
in connection with investigating or defending against any such loss,
claim, damage, liability or action.

This Limited Power of Attorney shall remain in full force and effect
until the undersigned is no longer required to file Forms 3, 4s and 5s
with respect to the undersigned's holdings of and transactions in
securities issued by the Company, unless earlier revoked by the
undersigned in a signed writing delivered to the foregoing attorneys-
in-fact.

IN WITNESS WHEREOF, the undersigned has caused this Limited Power of
Attorney to be executed as of November 18, 2025.

/s/ Alan Sachs Name: Alan Sachs