Quanterix (QTRX) CFO reports 274 shares withheld for RSU tax obligations

Rhea-AI Filing Summary

Quanterix Corporation’s Chief Financial Officer, Sriram Vandana, reported an automatic share withholding related to equity compensation. On 01/15/2026, 274 shares of Quanterix common stock were withheld by the company at a price of $7.95 per share solely to cover tax obligations upon the vesting of 777 restricted stock units (RSUs).

Following this tax withholding, Vandana beneficially owned 86,013 shares of Quanterix common stock, which includes 68,562 RSUs. The company’s year-end reconciliation identified a variance of 310 shares, and the corrected balance is reflected in the reported holdings.

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

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)
01/16/2026

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	01/15/2026	01/16/2026	F		274(1)	D	$7.95	86,013(2)(3)	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 vesting of 777 restricted stock units (RSUs).

2. Includes 68,562 RSUs.

3. QTRX year-end reconciliation revealed a variance of 310 shares. Corrected balance as shown

Remarks:

	/s/ Bonnie McManus, as Attorney-in-Fact	01/20/2026
	** 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.

FAQ

What insider transaction did Quanterix (QTRX) report in this Form 4?

The Form 4 reports that Chief Financial Officer Sriram Vandana had 274 shares of Quanterix common stock withheld by the company to cover tax obligations tied to vesting restricted stock units.

Was the Quanterix (QTRX) CFO’s Form 4 transaction an open market sale?

No. The filing states that 274 shares were withheld by Quanterix Corporation solely to cover tax obligations upon vesting of 777 RSUs, rather than sold in an open market transaction.

How many Quanterix (QTRX) shares does the CFO beneficially own after this transaction?

After the tax withholding, Chief Financial Officer Sriram Vandana beneficially owned 86,013 shares of Quanterix common stock.

How many restricted stock units (RSUs) are included in the Quanterix CFO’s holdings?

The filing notes that Vandana’s reported holdings include 68,562 restricted stock units (RSUs) as part of the total beneficial ownership.

What does the year-end reconciliation note in the Quanterix (QTRX) Form 4 mean?

The Form 4 explains that a QTRX year-end reconciliation revealed a variance of 310 shares, and the corrected balance of 86,013 shares is shown as the updated beneficial ownership.

What does Transaction Code "F" indicate in this Quanterix (QTRX) Form 4?

Transaction Code "F" indicates that the reported shares were withheld by the issuer to cover tax obligations associated with an equity award, in this case vesting RSUs.