Jonathan D Mariner Form 3 OneStream / JONATHAN D MARINER ownership change

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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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1. Name and Address of Reporting Person^*

MARINER JONATHAN D

(Last) (First) (Middle)

C/O ONESTREAM, INC.

191 N. CHESTER STREET

(Street)

BIRMINGHAM MI 48009

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
07/24/2024

3. Issuer Name and Ticker or Trading Symbol
OneStream, Inc. [ OS ]

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

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

5. 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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Common Units	(1)	(1)	Class A Common Stock	325,233	0	D
Common Units	(1)	(1)	Class A Common Stock	46,079	0	I	See footnote(2)
Common Units	(1)	(1)	Class A Common Stock	46,079	0	I	See footnote(3)
Stock Option (right to buy)	(4)	06/21/2034	Class A Common Stock	50,000	16.4	D
Stock Option (right to buy)	(5)	07/22/2034	Class A Common Stock	134,913	20	D

Explanation of Responses:

1. The Common Units may be redeemed by the Reporting Person at any time on or following the closing of the Initial Public Offering for shares of Class A Common Stock on a 1-to-1 basis, and a corresponding number of shares of Class C Common Stock will be forfeited in connection with the redemption. The Common Units have no expiration date.

2. The Common Units held of record by the Jonathan D. Mariner Revocable Trust, or the Mariner Revocable Trust, of which the Reporting Person is a trustee. By virtue of his relationship, the Reporting Person may be deemed to hold voting and dispositive power with respect to the Common Units held by the Mariner Revocable Trust.

3. The Common Units held of record by the Mariner Family Equity Trust, of which the Reporting Person is trustee. By virtue of his relationship, the Reporting Person may be deemed to hold voting and dispositive power with respect to the Common Units held by the Mariner Family Equity Trust.

4. One-fourth of the shares subject to the option shall vest on May 31, 2025, and 1/48th of the shares subject to the option shall vest each month thereafter, subject to the Reporting Person continuing to be a service provider through the applicable vesting date.

5. One-sixteenth of the shares subject to the option shall vest October 23, 2024, and one-sixteenth of the shares subject to the option shall vest every three months thereafter, subject to the Reporting Person continuing to be a service provider through the applicable vesting date.

	/s/ Holly Koczot, attorney-in-fact	07/24/2024
	** 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 5 (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.
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