OSS (OSS) CEO amends Form 4 to fix 21,000 RSU grant error

Rhea-AI Filing Summary

KNOWLES MICHAEL reported acquisition or exercise transactions in this Form 4 filing.

ONE STOP SYSTEMS, INC. Chief Executive Officer Michael Knowles filed an amended insider ownership report to correct a prior clerical error. A previous Form 4 had incorrectly shown a grant of 21,000 restricted stock units on May 21, 2025. The amendment reduces the number of shares reported as beneficially owned following that transaction by 21,000 shares. According to the corrected disclosure, Knowles beneficially owns 627,058 shares as of March 16, 2026, and the amendment does not reflect any change in beneficial ownership other than this reporting adjustment.

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^*

KNOWLES MICHAEL

(Last) (First) (Middle)

2235 ENTERPRISE STREET, SUITE 110

(Street)

ESCONDIDO CALIFORNIA 92029

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/21/2025

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)
09/02/2025

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	05/21/2025		A		0(1)	A	$0	591,653(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. This Form 4/A amends the Form 4 filed on September 2, 2025, solely to correct a clerical error in the prior report, which incorrectly reflected the grant of 21,000 restricted stock units on May 21, 2025.

2. As a result of this update, the number of shares beneficially owned by the Reporting Person following such transaction has been correspondingly decreased by 21,000 shares. As of March 16, 2026, the Reporting Person beneficially owns 627,058 shares. This amendment does not reflect any change in beneficial ownership other than as described above.

	/s/ Michael Knowles	03/27/2026
	** 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)

FAQ

What does the OSS (OSS) Form 4/A filing disclose about Michael Knowles?

The Form 4/A shows that CEO Michael Knowles corrected a clerical error in a prior insider report. It adjusts a previously misreported 21,000 restricted stock unit grant and updates his disclosed beneficial share ownership accordingly.

Why did ONE STOP SYSTEMS (OSS) CEO file an amended Form 4/A?

The CEO filed the amendment solely to correct a clerical error in an earlier Form 4. That prior report had incorrectly reflected a grant of 21,000 restricted stock units dated May 21, 2025, requiring a revision to the reported holdings.

How did the Form 4/A change Michael Knowles’ reported share ownership in OSS?

The amendment decreases the number of shares previously reported as beneficially owned after the May 21, 2025 transaction by 21,000 shares. It aligns the disclosed holdings with the actual grant details described in the corrected filing.

How many ONE STOP SYSTEMS (OSS) shares does Michael Knowles now beneficially own?

The filing states that, as of March 16, 2026, Michael Knowles beneficially owns 627,058 shares. This figure reflects the correction of the earlier 21,000 restricted stock unit grant reporting error and includes no additional ownership changes.

Does the OSS Form 4/A reflect any new insider transactions by the CEO?

The amendment does not record new insider buying or selling activity. It specifically notes that it does not reflect any change in beneficial ownership other than the adjustment tied to the previously misreported 21,000 restricted stock units.