Quanterix CTO converts 159 RSUs to shares

Quanterix Corp (QTRX) reported insider equity activity by Chief Technology Officer Michael Francis Miller.

Rhea-AI Filing Summary

Quanterix Corp (QTRX) reported insider equity activity by Chief Technology Officer Michael Francis Miller. On August 31, 2026, 159 restricted stock units converted into 159 shares of common stock, and 48 of those shares were delivered or withheld at $2.67 per share for payment of exercise price or tax liability. The RSU award referenced in this filing was part of a 6,278-unit grant originally awarded on September 23, 2022, with vesting over four years.

Insider Trade Summary

159 shares exercised/converted

Exercise 3 txns

Insider Miller Michael Francis

Role Chief Technology Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Unit F2	159	$0.00	$0.00
Exercise	Common Stock F1	159	--	--
Exercise Price or Tax Liability	Common Stock	48	$2.67	$128.16

Holdings After Transaction: Restricted Stock Unit — 0 contracts (Direct); Common Stock — 37,361 shares (Direct)

Footnotes (2)

1. F1. Restricted stock units convert into common stock on a one-for-one basis.
2. F2. On September 23, 2022, the reporting person was granted 6,278 restricted stock units, vesting 25% on the first anniversary of the grant date, with the remaining 75% vesting in 36 equal monthly installments on the last day of each month thereafter.

Key Figures

RSUs converted: 159 restricted stock units Common shares acquired on conversion: 159 shares Shares delivered or withheld: 48 shares +4 more

7 metrics

RSUs converted 159 restricted stock units Converted into common stock on August 31, 2026

Common shares acquired on conversion 159 shares Issued upon RSU conversion on August 31, 2026

Shares delivered or withheld 48 shares Used for payment of exercise price or tax liability

Per-share amount for tax or exercise payment $2.67 per share Applied to 48 shares under transaction code F

Original RSU grant size 6,278 restricted stock units Granted on September 23, 2022 with four-year vesting schedule

Initial cliff vesting portion 25% Of 6,278 RSUs vesting on first anniversary of grant date

Remaining vesting installments 36 monthly installments Covering remaining 75% of the 6,278 RSUs

Key Terms

Restricted Stock Unit, Exercise or conversion of derivative security, Payment of exercise price or tax liability, vesting in 36 equal monthly installments

4 terms

Restricted Stock Unit financial

"The reporting person held "Restricted Stock Unit" awards that converted"

A restricted stock unit is a promise from a company to give an employee shares of stock after certain conditions are met, like staying with the company for a set amount of time. It’s like earning a bonus that turns into company stock once you’ve proven your commitment, making it a way to motivate and reward employees.

Exercise or conversion of derivative security financial

"Transaction code M is described as "Exercise or conversion of derivative security""

Payment of exercise price or tax liability financial

"Transaction code F is "Payment of exercise price or tax liability by delivering""

vesting in 36 equal monthly installments financial

"The RSU grant vests 25% on the first anniversary, with the remaining 75% vesting "in 36 equal monthly installments""

FAQ

What did Quanterix (QTRX) CTO Michael Francis Miller report in this Form 4?

He reported the conversion of 159 restricted stock units into 159 shares of Quanterix common stock on August 31, 2026, with 48 shares delivered or withheld to cover exercise price or tax liability at $2.67 per share.

How many Quanterix (QTRX) RSUs were converted in this transaction?

A total of 159 restricted stock units were converted into 159 shares of Quanterix common stock on August 31, 2026, on a one-for-one basis under the terms of the RSU award.

What portion of the Quanterix (QTRX) shares were used for tax or exercise payments?

Out of the 159 common shares issued upon RSU conversion, 48 shares were delivered or withheld to pay the exercise price or tax liability at $2.67 per share, as reported under transaction code F.

What is the origin of the RSUs in this Quanterix (QTRX) Form 4?

The RSUs came from a grant of 6,278 restricted stock units awarded on September 23, 2022, vesting 25% on the first anniversary and the remaining 75% in 36 equal monthly installments thereafter.

Does this Quanterix (QTRX) Form 4 indicate an open-market stock sale by the CTO?

No. The transactions reflect RSU conversion into common stock and 48 shares delivered or withheld for payment of exercise price or tax liability, rather than an open-market purchase or sale.

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Available on EDGAR 09/01/2026 - 04:07 PM Accepted by SEC EDGAR 09/01/2026 - 04:07 PM Learn about SEC filing dates

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).

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^*

Miller Michael Francis

(Last) (First) (Middle)

C/O QUANTERIX CORPORATION

900 MIDDLESEX TURNPIKE

(Street)

BILLERICA MASSACHUSETTS 01821

(City) (State) (Zip)

UNITED STATES

(Country)

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 Technology Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/31/2026

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

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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

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	08/31/2026		M		159	A	(1)	37,409	D
Common Stock	08/31/2026		F		48	D	$2.67	37,361	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
Restricted Stock Unit	$0.00	08/31/2026		M			159	(2)	(2)	Common Stock	159	$0.00	0.00	D

Explanation of Responses:

1. Restricted stock units convert into common stock on a one-for-one basis.

2. On September 23, 2022, the reporting person was granted 6,278 restricted stock units, vesting 25% on the first anniversary of the grant date, with the remaining 75% vesting in 36 equal monthly installments on the last day of each month thereafter.

Remarks:

	/s/ Meghan Shevlin, Attorney-in-Fact	09/01/2026
	** 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.
* Form 4: SEC 1474 (03-26)