Miller Michael Francis 4

4 · Quanterix Corp · Filed Mar 17, 2026

AI-generated summary of this filing

Updated Mar 17, 2026

Quanterix (QTRX) COO Michael Miller Converts RSUs, Nets 1,009 Shares

What Happened

Michael Francis Miller, Chief Operating Officer of Quanterix (QTRX), had restricted stock units (RSUs) vest/convert on March 15, 2026. A total of 1,558 RSUs converted into common shares.
Of those, 549 shares were withheld to satisfy tax withholding at $4.72 per share (total tax withholding reported $2,592), leaving 1,009 net shares issued to Miller.
This was a routine vesting/settlement event (conversion of RSUs), not an open-market purchase or sale.

Key Details

Transaction date: March 15, 2026; Form 4 filed March 17, 2026 (appears timely—filed two days after the transactions).
Reported entries: several M-code conversions (derivative conversions of RSUs) totaling 1,558 shares acquired and matching derivative cancellations; F-code disposals (tax withholding) totaling 549 shares at $4.72/share, $2,592 total.
Net new shares received by Miller: 1,009 shares (1,558 converted − 549 withheld).
Shares owned after the transaction: not specified in the information provided on this filing.
Relevant footnotes: the converted RSUs came from multiple grants (see grant dates and sizes in the filing): Feb 6, 2023 (3,929 RSUs), Mar 15, 2023 (6,566 RSUs), Feb 2, 2024 (6,494 RSUs), May 21, 2024 (17,878 RSUs), Feb 4, 2025 (40,036 RSUs). Each award vests 25% at the first anniversary, then monthly installments on the 15th thereafter.

Context

These entries reflect routine RSU vesting and conversion into common stock. The F-code "disposals" are withholding of shares to cover tax obligations (a common practice), not open-market sales that would signal a cash exit.
Transaction codes: M = exercise/conversion of derivative (RSU conversion); F = payment of exercise price or tax liability (share withholding).
For retail investors: vesting conversions are standard compensation events and do not by themselves imply a change in the insider’s view of the company.

Form 4

Period: 2026-03-15

Chief Operating Officer

Transactions

Exercise/Conversion
Common Stock
[F1]
2026-03-15+81→ 30,343 total
Tax Payment
Common Stock
2026-03-15$4.72/sh−29$137→ 30,314 total
Exercise/Conversion
Common Stock
[F1]
2026-03-15+136→ 30,450 total
Tax Payment
Common Stock
2026-03-15$4.72/sh−48$227→ 30,402 total
Exercise/Conversion
Common Stock
[F1]
2026-03-15+135→ 30,537 total
Tax Payment
Common Stock
2026-03-15$4.72/sh−48$227→ 30,489 total
Exercise/Conversion
Common Stock
[F1]
2026-03-15+372→ 30,861 total
Tax Payment
Common Stock
2026-03-15$4.72/sh−131$618→ 30,730 total
Exercise/Conversion
Common Stock
[F1]
2026-03-15+834→ 31,564 total
Tax Payment
Common Stock
2026-03-15$4.72/sh−293$1,383→ 31,271 total
Exercise/Conversion
Restricted Stock Unit
[F2]
2026-03-15−81→ 922 total
Exercise: $0.00→ Common Stock (81 underlying)
Exercise/Conversion
Restricted Stock Unit
[F3]
2026-03-15−136→ 1,661 total
Exercise: $0.00→ Common Stock (136 underlying)
Exercise/Conversion
Restricted Stock Unit
[F4]
2026-03-15−135→ 3,116 total
Exercise: $0.00→ Common Stock (135 underlying)
Exercise/Conversion
Restricted Stock Unit
[F5]
2026-03-15−372→ 9,689 total
Exercise: $0.00→ Common Stock (372 underlying)
Exercise/Conversion
Restricted Stock Unit
[F6]
2026-03-15−834→ 8,855 total
Exercise: $0.00→ Common Stock (834 underlying)

Footnotes (6)

[F1]Restricted stock units convert into common stock on a one-for-one basis.
[F2]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.
[F3]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.
[F4]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.
[F5]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.
[F6]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.

Signature

/s/ Bonnie McManus, Attorney-in-Fact|2026-03-17

2 files