Was the 341-share disposition by System1 (SST) insider Weinrot an open-market sale?

No, it was not an open-market sale. The 341 shares were withheld by the company to cover Weinrot’s tax withholding obligation arising from the vesting of 670 RSUs, a routine administrative equity compensation process.

System1 (NYSE: SST) counsel has 341 shares withheld in RSU tax event

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

Form Type

Rhea-AI Filing Summary

System1, Inc. General Counsel & Secretary Daniel J. Weinrot reported a routine tax-related share disposition. When 670 restricted stock units (RSUs) vested, the company withheld 341 shares of Class A Common Stock at $2.26 per share to cover his tax withholding obligation.

After this non-market transaction, Weinrot directly holds 69,053 shares of Class A Common Stock, which include 54,510 unvested RSUs. The filing reflects compensation-related equity vesting rather than an open-market purchase or sale.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Weinrot Daniel J

Role General Counsel & Secretary

Type	Security	Shares	Price	Value
Tax Withholding	Class A Common Stock	341	$2.26	$770.66

Holdings After Transaction: Class A Common Stock — 69,053 shares (Direct)

Footnotes (1)

Upon the vesting of 670 restricted stock units ("RSUs") previously granted to the reporting person, the Company withheld 341 shares to cover the reporting person's tax withholding obligation with respect to the vesting of such RSUs. Includes 54,510 unvested RSUs.

Key Figures

Shares withheld for taxes: 341 shares RSUs vested: 670 RSUs Shares held after transaction: 69,053 shares +2 more

5 metrics

Shares withheld for taxes 341 shares Withheld to cover tax obligation on RSU vesting at $2.26

RSUs vested 670 RSUs Restricted stock units vesting triggered tax withholding

Shares held after transaction 69,053 shares Direct holdings after tax-withholding disposition, includes unvested RSUs

Unvested RSUs included in holdings 54,510 RSUs Unvested restricted stock units remaining after the transaction

Price per share for withholding $2.26 per share Value used for 341 shares withheld for tax obligation

Key Terms

restricted stock units ("RSUs"), tax withholding obligation, unvested RSUs, Class A Common Stock

4 terms

restricted stock units ("RSUs") financial

"Upon the vesting of 670 restricted stock units ("RSUs") previously granted"

Restricted stock units (RSUs) are a company promise to give an employee shares of stock (or cash equivalent) in the future, but only after certain conditions—usually staying with the company for a set time or hitting performance goals—are met. Investors watch RSUs because when they vest they increase the number of shares outstanding and can lead insiders to sell shares, affecting share price, company dilution and the true cost of employee pay.

tax withholding obligation financial

"the Company withheld 341 shares to cover the reporting person's tax withholding obligation"

unvested RSUs financial

"Includes 54,510 unvested RSUs."

Class A Common Stock financial

"security_title": "Class A Common Stock""

Class A common stock is a category of a company’s shares that carries a specific set of ownership rights—most commonly defined voting power and claims on dividends—set out in the company’s charter. For investors it matters because the class determines how much influence you have over corporate decisions, the share’s likely dividend and trading behavior, and how it compares in value to other share classes, like choosing a particular seat with different privileges at the company’s decision-making table.

Form 4 Insider Transactions: What Each Field Means →

04/17/2026 - 08:31 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^*

Weinrot Daniel J

(Last)

(First)

(Middle)

4235 REDWOOD AVE

(Street)

LOS ANGELES

CALIFORNIA

90066

(City)

(State)

(Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
System1, Inc. [ SST ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	General Counsel & Secretary

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)
Class A Common Stock	04/15/2026		F		341⁽¹⁾	D	$2.26	69,053⁽²⁾	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)

Explanation of Responses:

1. Upon the vesting of 670 restricted stock units ("RSUs") previously granted to the reporting person, the Company withheld 341 shares to cover the reporting person's tax withholding obligation with respect to the vesting of such RSUs.

2. Includes 54,510 unvested RSUs.

Remarks:

	/s/ Daniel J Weinrot	04/17/2026
	** 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 did System1 (SST) insider Daniel J. Weinrot report in this Form 4?

Daniel J. Weinrot reported a tax-withholding disposition of 341 shares. The company withheld these shares when 670 RSUs vested to cover his tax obligation, a standard compensation-related equity event rather than an open-market trade.

How many System1 (SST) shares were withheld for taxes from Weinrot’s RSU vesting?

The company withheld 341 shares of Class A Common Stock for taxes. This occurred upon vesting of 670 previously granted restricted stock units, satisfying Weinrot’s tax withholding obligation tied to that RSU vesting event.

What are Daniel J. Weinrot’s holdings in System1 (SST) after the reported transaction?

Following the transaction, Weinrot directly holds 69,053 shares of Class A Common Stock. This amount includes 54,510 unvested restricted stock units, reflecting both currently owned shares and equity awards that continue to vest over time.

What role does Daniel J. Weinrot hold at System1 (SST) in this Form 4 filing?

Daniel J. Weinrot is identified as General Counsel & Secretary of System1, Inc. His reported equity activity relates to his compensation, specifically RSU vesting and associated tax withholding, rather than discretionary stock market trading.