Quanterix (NASDAQ: QTRX) CFO nets shares after RSU vesting and tax withholding

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

Form Type

Rhea-AI Filing Summary

Quanterix Corp Chief Financial Officer Sriram Vandana reported routine equity compensation activity involving restricted stock units that converted into common stock. On April 15, 2026, restricted stock units converted into common stock on a one-for-one basis, delivering 263, 514 and 1,056 shares in separate tranches.

Related common stock entries show 263, 514 and 1,056-share acquisitions at a price of $0.00 per share. To satisfy tax obligations, 79, 154 and 315 shares of common stock were withheld at $3.60 per share as tax-withholding dispositions, rather than open-market sales.

Following these transactions, the filing shows Sriram Vandana directly holding 28,713 shares of Quanterix common stock. The derivative section lists no remaining restricted stock units tied to these specific conversions, underscoring that the reported activity reflects compensation vesting and associated tax withholding.

Insider Trade Summary

1,833 shares exercised/converted

Mixed 9 txns

Insider Sriram Vandana

Role Chief Financial Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Unit	263	$0.00	--
Exercise	Restricted Stock Unit	514	$0.00	--
Exercise	Restricted Stock Unit	1,056	$0.00	--
Exercise	Common Stock	263	$0.00	--
Tax Withholding	Common Stock	79	$3.60	$284.40
Exercise	Common Stock	514	$0.00	--
Tax Withholding	Common Stock	154	$3.60	$554.40
Exercise	Common Stock	1,056	$0.00	--
Tax Withholding	Common Stock	315	$3.60	$1K

Holdings After Transaction: Restricted Stock Unit — 4,208 shares (Direct); Common Stock — 27,691 shares (Direct)

Footnotes (1)

Restricted stock units convert into common stock on a one-for-one basis. On August 21, 2023, the reporting person was granted 12,624 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 24,675 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 50,712 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.

Key Figures

RSU conversions: 263, 514, 1,056 shares Tax-withholding shares: 79, 154, 315 shares Tax-withholding price: $3.60 per share +3 more

6 metrics

RSU conversions 263, 514, 1,056 shares Restricted stock units converting into common stock on April 15, 2026

Tax-withholding shares 79, 154, 315 shares Common stock withheld at $3.60 per share for tax obligations

Tax-withholding price $3.60 per share Price used to value common shares withheld for taxes

Direct holdings after transactions 28,713 shares Quanterix common stock directly owned by CFO after April 15, 2026 activity

Exercise transactions 3 entries, 1,833 shares Derivative exercises/conversions summarized in transaction data

Tax-withholding summary 3 entries, 548 shares Shares delivered to satisfy tax liabilities on vesting

Key Terms

Restricted Stock Unit, tax-withholding disposition, derivative security, vest, +1 more

5 terms

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.

vest financial

"vesting 25% on the first anniversary of the grant date"

A vest is the process by which an employee earns the right to receive certain benefits or ownership interests, such as stock or retirement funds, over time. It’s similar to earning a reward gradually, ensuring that the benefit becomes fully yours only after a set period or meeting specific conditions. This makes it important for investors because it determines when they can actually claim or use those benefits.

monthly installments financial

"the remaining 75% vesting in 36 equal monthly installments"

Monthly installments are regular, fixed payments made each month to gradually pay off a larger amount, such as a loan or purchase. Think of it like paying for a big item in small, manageable parts instead of all at once. For investors, understanding installment payments helps gauge how debts are structured and how they might affect financial stability or cash flow over time.

Form 4 Insider Transactions: What Each Field Means →

04/17/2026 - 04:58 PM

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^*

Sriram Vandana

(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 Financial Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/15/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	04/15/2026		M		263	A	⁽¹⁾	27,691	D
Common Stock	04/15/2026		F		79	D	$3.6	27,612	D
Common Stock	04/15/2026		M		514	A	⁽¹⁾	28,126	D
Common Stock	04/15/2026		F		154	D	$3.6	27,972	D
Common Stock	04/15/2026		M		1,056	A	⁽¹⁾	29,028	D
Common Stock	04/15/2026		F		315	D	$3.6	28,713	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Restricted Stock Unit	$0.00	04/15/2026		M			263	⁽²⁾	⁽²⁾	Common Stock	263	$0.00	4,208	D
Restricted Stock Unit	$0.00	04/15/2026		M			514	⁽³⁾	⁽³⁾	Common Stock	514	$0.00	11,311	D
Restricted Stock Unit	$0.00	04/15/2026		M			1,056	⁽⁴⁾	⁽⁴⁾	Common Stock	1,056	$0.00	35,922	D

Explanation of Responses:

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

2. On August 21, 2023, the reporting person was granted 12,624 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 February 2, 2024, the reporting person was granted 24,675 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 4, 2025, the reporting person was granted 50,712 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/ Bonnie McManus, as Attorney-in-Fact	04/16/2026
	** 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)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transactions did Quanterix (QTRX) CFO report on April 15, 2026?

Quanterix CFO Sriram Vandana reported restricted stock units converting into common stock on April 15, 2026. The filing lists 263, 514 and 1,056 RSUs converting one-for-one into common shares as part of routine equity compensation vesting.

How many Quanterix (QTRX) shares were acquired through RSU conversions?

The filing shows three RSU tranches converting into common stock: 263, 514 and 1,056 shares. Each restricted stock unit converts into one share of common stock, reflecting scheduled vesting of previously granted equity awards to the CFO.

Were any Quanterix (QTRX) shares sold by the CFO in this Form 4?

The transactions include tax-withholding dispositions, not open-market sales. The filing shows 79, 154 and 315 shares of common stock withheld at $3.60 per share to cover tax obligations tied to the restricted stock unit vesting.

What is the Quanterix (QTRX) CFO’s direct shareholding after these transactions?

After the reported transactions, the Form 4 shows CFO Sriram Vandana directly holding 28,713 shares of Quanterix common stock. This figure reflects net holdings after the RSU conversions and the related tax-withholding share dispositions.

How do Quanterix (QTRX) restricted stock units convert into common stock?

The filing states that Quanterix restricted stock units convert into common stock on a one-for-one basis. As tranches vest, each RSU delivers one share of common stock, subject to tax withholding obligations satisfied by delivering a portion of the shares.

What vesting schedules apply to the Quanterix (QTRX) CFO’s RSU grants?

The CFO received RSU grants on August 21, 2023, February 2, 2024, and February 4, 2025, each vesting 25% on the first anniversary. The remaining 75% vests in 36 equal monthly installments on the 15th day of each month thereafter.