STOCK TITAN

Quanterix (QTRX) CTO exercises 1,558 RSUs; 467 shares withheld for taxes

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Quanterix Corp Chief Technology Officer Michael Francis Miller reported routine equity compensation activity on June 15, 2026. He exercised derivative awards for a total of 1,558 common shares and used 467 shares, valued at $3.10 each, to cover tax obligations. Following these transactions, he directly holds 33,851 shares of common stock, and restricted stock units continue to vest over time under previously granted awards.

Positive

  • None.

Negative

  • None.
Insider Miller Michael Francis
Role Chief Technology Officer
Type Security Shares Price Value
Exercise Restricted Stock Unit 81 $0.00 --
Exercise Restricted Stock Unit 136 $0.00 --
Exercise Restricted Stock Unit 135 $0.00 --
Exercise Restricted Stock Unit 372 $0.00 --
Exercise Restricted Stock Unit 834 $0.00 --
Exercise Common Stock 81 $0.00 --
Tax Withholding Common Stock 25 $3.10 $77.50
Exercise Common Stock 136 $0.00 --
Tax Withholding Common Stock 41 $3.10 $127.10
Exercise Common Stock 135 $0.00 --
Tax Withholding Common Stock 41 $3.10 $127.10
Exercise Common Stock 372 $0.00 --
Tax Withholding Common Stock 111 $3.10 $344.10
Exercise Common Stock 834 $0.00 --
Tax Withholding Common Stock 249 $3.10 $771.90
Holdings After Transaction: Restricted Stock Unit — 679 shares (Direct, null); Common Stock — 33,876 shares (Direct, null)
Footnotes (1)
  1. Restricted stock units convert into common stock on a one-for-one basis. On February 6, 2023, the reporting person was granted 3,929 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 15th day of each month thereafter. On March 15, 2023, the reporting person was granted 6,566 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 15th day of each month thereafter. On February 2, 2024, the reporting person was granted 6,494 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 15th day of each month thereafter. On May 21, 2024, the reporting person was granted 17,878 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 15th day of each month thereafter. On February 4, 2025, the reporting person was granted 40,036 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 15th day of each month thereafter.
Shares acquired via exercises 1,558 shares Common stock from derivative exercises on June 15, 2026
Shares withheld for taxes 467 shares at $3.10 Tax-withholding dispositions on June 15, 2026
Common shares held after transactions 33,851 shares Direct ownership following June 15, 2026 activity
RSUs exercised (single grant example) 834 units Restricted stock units converting one-for-one into common stock
Earliest RSU grant cited 3,929 units Grant on February 6, 2023 with staged vesting
Largest RSU grant cited 40,036 units Grant on February 4, 2025 with 25% cliff and monthly vesting
Remaining RSUs (smallest balance shown) 679 units Restricted stock units outstanding after one grant’s conversions
Restricted stock unit financial
"Restricted stock units convert into common stock on a one-for-one basis."
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.
tax-withholding disposition financial
"Payment of exercise price or tax liability by delivering securities."
A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.
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.
vesting financial
"Vesting 25% on the first anniversary, remaining 75% in 36 monthly installments."
Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.
exercise or conversion financial
"Exercise or conversion of derivative security."
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SEC Form 4
FORM 4UNITED 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)
Director10% Owner
XOfficer (give title below)Other (specify below)
Chief Technology Officer
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/15/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock06/15/2026M81A(1)33,876D
Common Stock06/15/2026F25D$3.133,851D
Common Stock06/15/2026M136A(1)33,987D
Common Stock06/15/2026F41D$3.133,946D
Common Stock06/15/2026M135A(1)34,081D
Common Stock06/15/2026F41D$3.134,040D
Common Stock06/15/2026M372A(1)34,412D
Common Stock06/15/2026F111D$3.134,301D
Common Stock06/15/2026M834A(1)35,135D
Common Stock06/15/2026F249D$3.134,886D
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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Restricted Stock Unit$0.0006/15/2026M81 (2) (2)Common Stock81$0.00679D
Restricted Stock Unit$0.0006/15/2026M136 (3) (3)Common Stock136$0.001,253D
Restricted Stock Unit$0.0006/15/2026M135 (4) (4)Common Stock135$0.002,711D
Restricted Stock Unit$0.0006/15/2026M372 (5) (5)Common Stock372$0.008,573D
Restricted Stock Unit$0.0006/15/2026M834 (6) (6)Common Stock834$0.0026,691D
Explanation of Responses:
1. Restricted stock units convert into common stock on a one-for-one basis.
2. On February 6, 2023, the reporting person was granted 3,929 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 15th day of each month thereafter.
3. On March 15, 2023, the reporting person was granted 6,566 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 15th day of each month thereafter.
4. On February 2, 2024, the reporting person was granted 6,494 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 15th day of each month thereafter.
5. On May 21, 2024, the reporting person was granted 17,878 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 15th day of each month thereafter.
6. On February 4, 2025, the reporting person was granted 40,036 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 15th day of each month thereafter.
Remarks:
/s/ Meghan Shevlin, Attorney-in-Fact06/16/2026
** Signature of Reporting PersonDate
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)

FAQ

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

Michael Miller reported routine equity compensation activity. He exercised derivative awards for 1,558 common shares and used 467 shares to satisfy tax obligations at $3.10 per share, with no open-market buying or selling disclosed.

How many Quanterix (QTRX) shares does the CTO hold after these Form 4 transactions?

After the reported transactions, Michael Miller directly holds 33,851 shares of Quanterix common stock. This total reflects net shares following derivative exercises and share withholdings used to cover related tax liabilities on June 15, 2026.

Were Quanterix (QTRX) shares sold on the open market in this Form 4?

No open-market sales are indicated. The Form 4 shows tax-withholding dispositions coded “F,” meaning 467 shares were delivered at $3.10 per share to cover tax obligations tied to equity awards, not discretionary market selling.

What derivative securities did the Quanterix (QTRX) CTO exercise in this filing?

The CTO exercised restricted stock units and related derivative awards that convert one-for-one into common stock. In total, 1,558 common shares were acquired through these exercises, reflecting vesting of previously granted restricted stock units on June 15, 2026.

How are Quanterix (QTRX) restricted stock units structured for the CTO?

Restricted stock units convert into common stock on a one-for-one basis. Grants made between February 2023 and February 2025 typically vest 25% on the first anniversary of grant, with the remaining 75% vesting in 36 equal monthly installments.

Does this Quanterix (QTRX) Form 4 indicate large insider selling activity?

The filing reflects routine tax-withholding and vesting, not large discretionary selling. Dispositions totaled 467 shares for taxes, while 1,558 shares were acquired through derivative exercises, leaving the CTO with 33,851 common shares directly held.