Quanterix CTO converts RSUs, withholds 39 shares

Quanterix Corp Chief Technology Officer Michael Francis Miller reported the conversion of 130 restricted stock units into an equal number of common shares on July 31, 2026, from a 6,278-unit grant awarded September 23, 2022.

Rhea-AI Filing Summary

Quanterix Corp Chief Technology Officer Michael Francis Miller reported the conversion of 130 restricted stock units into an equal number of common shares on July 31, 2026, from a 6,278-unit grant awarded September 23, 2022. In a related transaction, 39 common shares were disposed of at $3.48 per share as payment of exercise price or tax liability. The filing does not affirm these transactions as made under a Rule 10b5-1 trading plan.

Insider Trade Summary

130 shares exercised/converted

Exercise 3 txns

Insider Miller Michael Francis

Role Chief Technology Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units F2	130	$0.00	$0.00
Exercise	Common Stock F1	130	--	--
Exercise Price or Tax Liability	Common Stock	39	$3.48	$135.72

Holdings After Transaction: Restricted Stock Units — 159 contracts (Direct); Common Stock — 36,159 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: 130 shares Shares disposed for obligations: 39 shares Disposition price: $3.48 per share +3 more

6 metrics

RSUs converted 130 shares Restricted stock units converting into common stock on July 31, 2026

Shares disposed for obligations 39 shares Common shares delivered or withheld to pay exercise price or tax liability

Disposition price $3.48 per share Price for disposition of 39 common shares classified under code F

RSU grant size 6,278 units Restricted stock units granted to Miller on September 23, 2022

Initial vesting portion 25 % Portion of 6,278 RSUs vesting on the first anniversary of the grant date

Remaining vesting installments 36 installments Remaining 75% of RSUs vest in 36 equal monthly installments

Key Terms

Restricted stock units, derivative security, exercise price or tax liability, Common Stock

4 terms

Restricted stock units financial

"On September 23, 2022, the reporting person was granted 6,278 restricted stock units"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

derivative security financial

"Exercise or conversion of derivative security"

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

exercise price or tax liability financial

"Payment of exercise price or tax liability by delivering or withholding securities"

Common Stock financial

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

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did Quanterix (QTRX) CTO Michael Francis Miller report?

Miller reported 130 restricted stock units converting into common stock and a related disposition of 39 common shares at $3.48 per share as payment of exercise price or tax liability, all dated July 31, 2026.

How many Quanterix (QTRX) restricted stock units vested and converted into shares?

A total of 130 restricted stock units converted into 130 common shares on July 31, 2026. The RSUs convert on a one-for-one basis, as specified, tying directly to a prior equity grant.

What was the original Quanterix (QTRX) RSU grant and vesting schedule for Miller?

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

How many Quanterix (QTRX) shares were disposed of to cover obligations, and at what price?

Miller had 39 common shares disposed of at $3.48 per share. The transaction is classified as payment of exercise price or tax liability by delivering or withholding securities, rather than an open-market sale.

Were the Quanterix (QTRX) insider transactions made under a Rule 10b5-1 trading plan?

The filing’s Rule 10b5-1 checkbox is not marked as affirmative, so the transactions are not affirmed as being executed under a pre-arranged Rule 10b5-1 trading plan for Miller.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/04/2026 - 04:45 PM Accepted by SEC EDGAR 08/04/2026 - 04:45 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)
07/31/2026

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	07/31/2026		M		130	A	(1)	36,198	D
Common Stock	07/31/2026		F		39	D	$3.48	36,159	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 Units	$0.00	07/31/2026		M			130	(2)	(2)	Common Stock	130	$0.00	159	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	08/04/2026
	** 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)