System1 (NYSE: SST) GC logs 377-share tax withholding on RSU vesting

Rhea-AI Filing Summary

System1, Inc. officer Daniel J. Weinrot, General Counsel & Secretary, reported a tax-related share withholding tied to restricted stock unit (RSU) vesting. On January 15, 2026, 377 shares of Class A common stock were withheld by the company at a price of $4.40 per share to cover his tax obligation when 670 RSUs vested. After this transaction, he beneficially owns 69,605 shares of Class A common stock, which includes 55,555 unvested RSUs. The filing is made as a Form 4 for a single reporting person.

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

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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 CA 90066

(City) (State) (Zip)

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

3. Date of Earliest Transaction (Month/Day/Year)
01/15/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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
Class A Common Stock	01/15/2026		F		377(1)	D	$4.4	69,605(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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Upon the vesting of 670 restricted stock units ("RSUs") previously granted to the reporting person, the Company withheld 377 shares to cover the reporting person's tax withholding obligation with respect to the vesting of such RSUs.

2. Includes 55,555 unvested RSUs.

Remarks:

	/s/ Daniel J Weinrot	01/16/2026
	** 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.

FAQ

What insider transaction did SST officer Daniel Weinrot report on this Form 4?

Daniel J. Weinrot, General Counsel & Secretary of System1, Inc. (SST), reported that on January 15, 2026 the company withheld 377 shares of Class A common stock at $4.40 per share to satisfy his tax withholding obligation related to vested restricted stock units.

Was the 377-share SST transaction a market sale by Daniel Weinrot?

No. The 377 shares of System1 Class A common stock were withheld by the company to cover Daniel Weinrot’s tax withholding on the vesting of 670 RSUs, rather than being sold on the open market.

What does transaction code "F" mean in Daniel Weinrot’s SST Form 4?

Transaction code "F" indicates a tax withholding transaction, where shares are withheld by the issuer to pay taxes due upon the vesting or exercise of equity awards, such as the 670 RSUs that vested for Daniel Weinrot.

How many SST shares does Daniel Weinrot own after this reported transaction?

After the tax withholding of 377 shares, Daniel Weinrot beneficially owns 69,605 shares of System1 Class A common stock, which the filing notes includes 55,555 unvested RSUs.

What RSU holdings are disclosed for Daniel Weinrot in this SST filing?

The filing explains that 670 RSUs vested, triggering the tax withholding, and that Daniel Weinrot’s reported beneficial ownership includes 55,555 unvested RSUs that remain subject to vesting conditions.

Is Daniel Weinrot a director or a 10% owner of System1, Inc. (SST)?

No. The Form 4 identifies Daniel J. Weinrot solely as an officer of System1, Inc., with the title General Counsel & Secretary, and does not mark him as a director or 10% owner.