System1, Inc. Insider Trading Activity

Accepted by SEC EDGAR 07/30/2025 - 07:39 PM EDT Learn about SEC filing dates

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Sestanovich Elizabeth

Role Chief People Officer

Type	Security	Shares	Price	Value
Grant/Award	Class A Common Stock	40,000	$0.00	$0.00
Exercise Price or Tax Liability	Class A Common Stock	135	$7.51	$1K

Holdings After Transaction: Class A Common Stock — 60,317 shares (Direct)

Footnotes (4)

1. F1. Upon the vesting of 375 restricted stock units ("RSUs") previously granted to the reporting person, the Company withheld 135 shares to cover the reporting person's tax withholding obligation with respect to the vesting of such RSUs.
2. F2. Includes 4,770 unvested RSUs.
3. F3. The Reporting Person was granted 40,000 restricted stock units ("RSUs") in connection with his continued employment with System1, Inc. ("SST"). Each RSU represents the right to receive one share of SST Class A Common Stock upon vesting. Subject to the continued employment of Ms. Sestanovich through the applicable vesting date, one-third of the RSUs will vest on July 15, 2026, and the remaining two-thirds will vest in 8 substantially equal quarterly installments on each quarterly anniversary thereafter.
4. F4. Includes 44,770 unvested RSUs.

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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^*

Sestanovich Elizabeth

(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)
	Chief People Officer

3. Date of Earliest Transaction (Month/Day/Year)
07/28/2025

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	07/28/2025		F		135(1)	D	$7.51	20,317(2)	D
Class A Common Stock	07/29/2025		A		40,000(3)	A	$0	60,317(4)	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 375 restricted stock units ("RSUs") previously granted to the reporting person, the Company withheld 135 shares to cover the reporting person's tax withholding obligation with respect to the vesting of such RSUs.

2. Includes 4,770 unvested RSUs.

3. The Reporting Person was granted 40,000 restricted stock units ("RSUs") in connection with his continued employment with System1, Inc. ("SST"). Each RSU represents the right to receive one share of SST Class A Common Stock upon vesting. Subject to the continued employment of Ms. Sestanovich through the applicable vesting date, one-third of the RSUs will vest on July 15, 2026, and the remaining two-thirds will vest in 8 substantially equal quarterly installments on each quarterly anniversary thereafter.

4. Includes 44,770 unvested RSUs.

Remarks:

	/s/ Daniel Weinrot, Attorney-in-Fact for Elizabeth Sestanovich	07/30/2025
	** 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.