[Form 4] Quanterix Corp Insider Trading Activity

Rhea-AI Filing Summary

Sriram Vandana, Chief Financial Officer of Quanterix Corporation (QTRX), reported a sale of common stock on 09/15/2025. The filing shows 229 shares disposed at a price of $4.97 per share, marked with code F and explained as shares withheld by the company to cover tax obligations arising from the vesting of 777 restricted stock units (RSUs). After the transaction, the reporting person beneficially owned 86,971 shares, which the filing notes includes 71,670 RSUs. The form is signed by an attorney-in-fact on behalf of the reporting person and reflects a routine tax-withholding disposition rather than an open-market sale for cash.

Positive

• Transaction is routine and compliance-driven, reflecting tax withholding on RSU vesting rather than opportunistic selling.
• Detailed disclosure provided including number of RSUs (777 vested), shares withheld (229), and post-transaction beneficial ownership (86,971).

Negative

• Minor reduction in direct shares held by the CFO due to withholding (229 shares disposed).

Insights

Corporate Governance Expert

TL;DR: Routine tax-withholding disposition on RSU vesting; no material change to governance or control.

This Form 4 documents a customary tax-withholding action tied to the vesting of 777 RSUs where the company withheld 229 shares to cover tax obligations. The transaction is labeled with code F, consistent with shares withheld rather than a voluntary market sale. The post-transaction beneficial ownership of 86,971 shares (including 71,670 RSUs) indicates continued significant equity exposure by the CFO. From a governance perspective, this is a standard administrative filing and does not signal a change in control, unusual insider liquidity, or a governance concern.

Securities Analyst

TL;DR: Small, routine disposition tied to RSU vesting; immaterial to share count and valuation.

The reported disposal of 229 shares at $4.97 per share reflects withholding to satisfy tax obligations on vested RSUs (777 units). The filing discloses that 71,670 RSUs remain included in the reporting person's beneficial holdings, and total beneficial ownership is 86,971 shares after the withholding. Given the small size of the withheld block relative to total outstanding shares typically seen for public companies, this transaction is unlikely to materially affect the company's float, valuation, or market dynamics. It is a compliance-driven filing rather than a directional insider trade.

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Sriram Vandana

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

3. Date of Earliest Transaction (Month/Day/Year)
09/15/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	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	09/15/2025		F		229(1)	D	$4.97	86,971(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. Shares withheld by Quanterix Corporation solely to cover tax obligations upon the vesting of 777 Restricted Stock Units.

2. Includes 71,670 Restricted Stock Units.

Remarks:

	/s/ Brian Keane, as Attorney-in-Fact	09/17/2025
	** 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.

FAQ

What transaction did the Quanterix (QTRX) filing report?

The Form 4 reports the disposal of 229 common shares on 09/15/2025 at $4.97 per share, marked as code F (shares withheld for taxes).

Why were shares disposed in the QTRX Form 4 by the CFO?

The filing explains the 229 shares were withheld by Quanterix to cover tax obligations arising from the vesting of 777 restricted stock units.

How many shares does the reporting person own after the transaction?

Following the reported transaction, the reporting person beneficially owned 86,971 shares, which the filing states includes 71,670 Restricted Stock Units.

Does the Form 4 indicate a market sale or an administrative withholding?

The transaction is reported with code F and explicitly described as shares withheld to cover taxes, indicating an administrative withholding rather than an open-market sale.

Who signed the Form 4 for the reporting person?

The form is signed by /s/ Brian Keane, as Attorney-in-Fact on behalf of the reporting person, dated 09/17/2025.