ONE STOP SYSTEMS, INC. — Director's Dealing 2026

Mar 2, 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ONE STOP SYSTEMS, INC. (OSS)
CIK: 0001394056
Period of Report: 2026-02-07

Reporting Person: Ison James (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-02-07	Common Stock	A	34313	—	Acquired	155836	Direct
2026-02-07	Common Stock	F	6546	$9.24	Disposed	149290	Direct
2026-02-07	Common Stock	G	8213	—	Disposed	141077	Direct
2026-02-07	Common Stock	G	8213	—	Acquired	226885	Indirect
2026-02-15	Common Stock	F	3120	$8.70	Disposed	146170	Direct
2026-02-15	Common Stock	G	4263	—	Disposed	141907	Direct
2026-02-15	Common Stock	G	4263	—	Acquired	231148	Indirect

Footnotes

F1: Represents 34,313 restricted stock units granted to the Reporting Person under the Company's 2017 Equity Incentive Plan (the "Plan") in connection with the Reporting Person's ongoing service of the executive management team.

F2: Includes 148,076 unvested restriced stock units held by the Reporting Person, all of which remain subject to certain vesting conditions.

F3: The Reporting Person forfeited 6,546 shares of common stock upon conversion of 14,759 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 February 7, 2025.

F4: Includes 133,317 unvested restricted stock units held by the Reporting Person, all of which remain subject to certain vesting conditions.

F5: On February 7, 2026 the Reporting Person transferred 8,213 shares of common stock to the James J. Ison Jr. & Sha-Marie A Ison TR UA 06 04 2020 James J. Ison Jr. & Shah-Marie A Ison Inter Vivos Revocable Trust (the "Trust"), of which the Reporting Person is trustee. The Reporting Person and members of his immediate family are the sole beneficiaries of the Trust.

F6: These shares are owned directly by the Trust, and indirectly by James Ison as trustee of the Trust.

F7: The Reporting Person forfeited 3,120 shares of common stock upon conversion of 7,383 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 July 1, 2024.

F8: Includes 125,934 unvested restricted stock units held by the Reporting Person, all of which remain subject to certain vesting conditions.

F9: On February 15, 2026 the Reporting Person transferred 4,263 shares of common stock to the James J. Ison Jr. & Sha-Marie A Ison TR UA 06 04 2020 James J. Ison Jr. & Shah-Marie A Ison Inter Vivos Revocable Trust (the "Trust"), of which the Reporting Person is trustee. The Reporting Person and members of his immediate family are the sole beneficiaries of the Trust.