OSS CEO forfeits shares to cover tax on RSUs

KNOWLES MICHAEL reported disposition transactions in this Form 4 filing.

Rhea-AI Filing Summary

KNOWLES MICHAEL reported disposition transactions in this Form 4 filing.

ONE STOP SYSTEMS, INC. CEO Michael Knowles reported a routine tax-related share forfeiture tied to vested equity compensation. He forfeited 19,675 shares of common stock at a value of $16.89 per share to cover tax withholdings when 50,000 vested restricted stock units converted into shares.

After this transaction, he directly holds 607,383 shares of common stock, which includes 333,311 unvested restricted stock units that remain subject to vesting conditions. The filing reflects compensation and tax mechanics rather than an open-market purchase or sale decision.

Insider Trade Summary

Exercise Price or Tax Liability: 19,675 shares

Exercise Price or Tax Liability 1 txn

Insider KNOWLES MICHAEL

Role Chief Executive Officer

Type	Security	Shares	Price	Value
Exercise Price or Tax Liability	Common Stock	19,675	$16.89	$332K

Holdings After Transaction: Common Stock — 607,383 shares (Direct)

Footnotes (2)

1. F1. The Reporting Person forfeited 19,675 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. F2. Includes 333,311 unvested restricted stock units held by the Reporting Person, all of which remain subject to certain vesting conditions.

Key Figures

Shares forfeited for taxes: 19,675 shares Implied share value: $16.89 per share RSUs converted: 50,000 units +2 more

5 metrics

Shares forfeited for taxes 19,675 shares Tax-withholding disposition on vested RSUs

Implied share value $16.89 per share Value used to cover tax withholdings

RSUs converted 50,000 units Vested restricted stock units converted to shares

Shares held after transaction 607,383 shares Direct holdings following tax-withholding forfeiture

Unvested RSUs remaining 333,311 units Unvested restricted stock units subject to vesting conditions

Key Terms

restricted stock units, tax withholdings, vesting conditions, Form 4

4 terms

restricted stock units financial

"These restricted stock units were part of the grant reported in Table I"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

tax withholdings financial

"to cover tax withholdings, using the market price of the issuer's common stock"

vesting conditions financial

"Includes 333,311 unvested restricted stock units held by the Reporting Person, all of which remain subject to certain vesting conditions"

Vesting conditions are the rules that determine when someone earning company stock or stock options actually gains the right to keep or sell them, typically based on staying with the company for a set time or meeting performance targets. Think of it like keys that unlock gradually — some unlock by calendar date, others only after agreed milestones. Investors care because vesting shapes management incentives, the timing of share sales, and the number of shares that can enter the market, which can affect a company's valuation and ownership mix.

Form 4 regulatory

"Form 4 filed by the Reporting Person with the Securities and Exchange Commission on June 6, 2023"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did OSS CEO Michael Knowles report?

Michael Knowles reported forfeiting 19,675 OSS common shares to cover tax withholdings. The shares were withheld when 50,000 vested restricted stock units converted into stock, reflecting compensation and tax mechanics rather than an open-market trade.

Was the OSS CEO’s Form 4 a stock sale on the open market?

No, the Form 4 shows a tax-withholding disposition, not an open-market sale. Shares were forfeited to satisfy tax obligations when restricted stock units vested and converted, which is a common administrative step for equity compensation.

How many OSS shares does CEO Michael Knowles hold after this transaction?

Following the transaction, Michael Knowles holds 607,383 OSS common shares directly. This total includes both already issued shares and 333,311 unvested restricted stock units that are still subject to future vesting conditions.

What triggered the tax-withholding disposition in the OSS Form 4?

The disposition was triggered when 50,000 vested and outstanding restricted stock units converted into OSS common shares. To cover related tax withholdings, 19,675 of those shares were forfeited using the market price at the time of forfeiture.

Do all 333,311 OSS restricted stock units held by the CEO vest immediately?

No, the 333,311 restricted stock units held by the CEO remain unvested and are subject to vesting conditions. They represent potential future OSS share ownership if vesting requirements are met over time under the applicable equity plan.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/12/2026 - 05:21 PM Learn about SEC filing dates

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^*

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)
06/05/2026

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)

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	06/05/2026		F		19,675(1)	D	$16.89	607,383(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 19,675 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 333,311 unvested restricted stock units held by the Reporting Person, all of which remain subject to certain vesting conditions.

	/s/ Michael Knowles	06/12/2026
	** 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)