ONE STOP SYSTEMS (OSS) CEO forfeits shares for taxes after RSU conversion

Rhea-AI Filing Summary

ONE STOP SYSTEMS, INC. CEO Michael Knowles reported a routine tax-related share forfeiture. On 12/31/2025 he forfeited 19,075 shares of common stock at $7.18 per share to cover tax withholdings when an aggregate 50,000 vested restricted stock units converted into common stock.

After this transaction, he beneficially owned 566,144 shares of common stock, including 368,173 unvested restricted stock units that remain subject to vesting conditions. The filing indicates the holdings are reported as directly owned.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider KNOWLES MICHAEL

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	19,075	$7.18	$137K

Holdings After Transaction: Common Stock — 566,144 shares (Direct)

Footnotes (1)

1. The Reporting Person forfeited 19,075 shares of common stock upon conversion of an aggregate 50,000 vested and outstanding restricted stock units into shares of common stock to cover tax withholdings, using the market price of the issuer's common stock at the time of forfeiture. These restricted stock units were part of the grant reported in Table I of the Form 4 filed by the Reporting Person with the Securities and Exchange Commission on June 6, 2023. Includes 368,173 unvested restricted stock units held by the Reporting Person, all of which remain subject to certain vesting conditions.

Form 4 Insider Transactions: What Each Field Means →

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
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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^*

KNOWLES MICHAEL

(Last) (First) (Middle)

2235 ENTERPRISE STREET, SUITE 110

(Street)

ESCONDIDO CA 92029

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
ONE STOP SYSTEMS, INC. [ OSS ]

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

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Executive Officer

3. Date of Earliest Transaction (Month/Day/Year)
12/31/2025

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
Common Stock	12/31/2025		F		19,075(1)	D	$7.18	566,144(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. The Reporting Person forfeited 19,075 shares of common stock upon conversion of an aggregate 50,000 vested and outstanding restricted stock units into shares of common stock to cover tax withholdings, using the market price of the issuer's common stock at the time of forfeiture. These restricted stock units were part of the grant reported in Table I of the Form 4 filed by the Reporting Person with the Securities and Exchange Commission on June 6, 2023.

2. Includes 368,173 unvested restricted stock units held by the Reporting Person, all of which remain subject to certain vesting conditions.

	/s/ Michael Knowles	01/05/2026
	** 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 OSS CEO Michael Knowles report on this Form 4?

He reported forfeiting 19,075 shares of ONE STOP SYSTEMS, INC. common stock on 12/31/2025 to cover tax withholdings tied to restricted stock units.

What does the forfeiture of 19,075 OSS shares by the CEO represent?

The 19,075-share forfeiture represents shares withheld to pay taxes upon conversion of an aggregate 50,000 vested restricted stock units into common stock, not an open-market sale.

How many OSS shares does the CEO own after this reported transaction?

Following the transaction, Michael Knowles beneficially owned 566,144 shares of OSS common stock, reported as directly held.

How many unvested restricted stock units does the OSS CEO still hold?

He holds 368,173 unvested restricted stock units, all of which remain subject to specified vesting conditions.

What was the price used for the OSS CEO’s tax withholding share forfeiture?

The forfeited 19,075 shares were valued at $7.18 per share, using the market price of ONE STOP SYSTEMS, INC. common stock at the time of forfeiture.

Is this OSS Form 4 filing for a direct or indirect ownership transaction?

The filing reports the CEO’s post-transaction holdings of 566,144 shares as direct ownership of ONE STOP SYSTEMS, INC. common stock.