SEC FORM 4

SEC FORM 4SEC 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^*

Shea Thomas Anthony

(Last)

(First)

(Middle)

C/O ONESTREAM, INC.

191 N. CHESTER STREET

(Street)

BIRMINGHAM

MICHIGAN

48009

(City)

(State)

(Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/01/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Class A Common Stock	04/01/2026		D⁽¹⁾		80,023	D	⁽²⁾	0	D
Class A Common Stock	04/01/2026		D⁽¹⁾		379,963	D	⁽³⁾	0	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Units	⁽⁴⁾	04/01/2026		D⁽¹⁾			325,232	⁽⁴⁾	⁽⁴⁾	Class D Common Stock	325,232	⁽⁴⁾	0	I	See footnote⁽⁵⁾
Class D Common Stock	⁽⁶⁾	04/01/2026		D⁽¹⁾			4,313,836	⁽⁶⁾	⁽⁶⁾	Class A Common Stock	4,313,836	⁽⁶⁾	0	D
Class D Common Stock	⁽⁶⁾	04/01/2026		D⁽¹⁾			2,814,351	⁽⁶⁾	⁽⁶⁾	Class A Common Stock	2,814,351	⁽⁶⁾	0	I	See footnote⁽⁷⁾
Class D Common Stock	⁽⁸⁾	04/01/2026		D⁽¹⁾			9,041,667	⁽⁸⁾	⁽⁸⁾	Class A Common Stock	9,041,667	⁽⁸⁾	0	I	See footnote⁽⁷⁾
Stock Option (right to buy)	$10.65	04/01/2026		D⁽¹⁾			619,835	⁽⁹⁾	12/04/2031	Class A Common Stock	619,835	⁽⁹⁾	0	D
Stock Option (right to buy)	$10.65	04/01/2026		D⁽¹⁾			504,472	⁽⁹⁾	03/05/2033	Class A Common Stock	504,472	⁽⁹⁾	0	D
Stock Option (right to buy)	$10.65	04/01/2026		D⁽¹⁾			149,979	⁽¹⁰⁾	03/05/2033	Class A Common Stock	149,979	⁽¹⁰⁾	0	D
Stock Option (right to buy)	$14.51	04/01/2026		D⁽¹⁾			473,008	⁽⁹⁾	03/10/2034	Class A Common Stock	473,008	⁽⁹⁾	0	D
Stock Option (right to buy)	$14.51	04/01/2026		D⁽¹⁾			435,161	⁽¹⁰⁾	03/10/2034	Class A Common Stock	435,161	⁽¹⁰⁾	0	D
Stock Option (right to buy)	$20	04/01/2026		D⁽¹⁾			55,795	⁽⁹⁾	07/22/2034	Class A Common Stock	55,795	⁽⁹⁾	0	D
Stock Option (right to buy)	$20	04/01/2026		D⁽¹⁾			92,992	⁽¹⁰⁾	07/22/2034	Class A Common Stock	92,992	⁽¹⁰⁾	0	D

Explanation of Responses:

1. Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated January 6, 2026, by and among OneStream, Inc. ("Issuer"), OneStream Software LLC, a subsidiary of Issuer ("Company LLC"), Onward AcquireCo Inc. ("Parent"), Onward Merger Sub 2, LLC ( "Merger Sub I") and Onward Merger Sub, Inc. ("Merger Sub II"), on April 1, 2026, Merger Sub 1 merged with and into Company LLC (the "First Merger"), with Company LLC surviving the First Merger and becoming a subsidiary of Parent, and Merger Sub II merged with and into Issuer (the "Second Merger" and together with the First Merger, the "Mergers"), with Issuer surviving the Second Merger and becoming a subsidiary of Parent.

2. Pursuant to the Merger Agreement, at the effective time of the Mergers (the "Effective Time"), each share of Issuer Class A Common Stock was cancelled and converted into the right to receive $24.00 per share in cash (the "Per Share Price") without interest, less applicable withholding taxes.

3. Represents an equal number of restricted stock units ("RSUs"). At the Effective Time, each unvested RSU award was cancelled and converted into the contingent right to receive a cash award, without interest, equal to the product of (a) the Per Share Price multiplied by (b) the total number of shares of Issuer's Class A Common Stock covered by such RSU award, less applicable withholding taxes. The vesting terms and conditions applicable to the unvested RSU awards as of immediately prior to the Mergers will remain in effect following the Mergers.

4. At the Effective Time, each Common Unit was cancelled and converted into the right to receive an amount in cash, without interest, equal to the Per Share Price, less applicable withholding taxes. Each corresponding share of Class C Common Stock was cancelled and converted into the right to receive $0.0001 in cash, without interest, less applicable withholding taxes.

5. Shares held of record by the TSICU Corp. TSICU Corp. is a subchapter S corporation controlled by the Reporting Person, who has sole voting and dispositive power over the shares held by it.

6. Pursuant to the Merger Agreement, at the Effective Time, each share of Class D Common Stock was cancelled and converted into the right to receive the Per Share Price, without interest, less applicable withholding taxes.

7. Shares held of record by the Shea Family Trust dated December 25, 2019 (the "2019 Shea Family Trust"). The Reporting Person's spouse serves as the co-trustee for the 2019 Shea Family Trust. By virtue of his relationship, the Reporting Person may be deemed to share voting and dispositive power with respect to the shares held by the 2019 Shea Family Trust.

8. At the Effective Time, the shares of Class D Common Stock were reinvested into Issuer, as a privately held entity following the Mergers, and were exchanged for equity interests in an entity that controls Parent.

9. At the Effective Time, each vested option was cancelled and converted into the right to receive an amount in cash, without interest, equal to the product of (a) the total number of shares of Class A Common Stock subject to the option multiplied by (b) the excess, if any, of the Per Share Price over the exercise price per share of the option, less applicable withholding taxes.

10. At the Effective Time, each unvested option was cancelled and converted into the contingent right to receive a cash award, without interest, equal to the product of (a) the total number of shares of Class A Common Stock subject to the option multiplied by (b) the excess, if any, of the Per Share Price over the exercise price per share of such option, less applicable withholding taxes. The vesting terms and conditions applicable to the unvested option as of immediately prior to the Mergers will remain in effect following the Mergers.

	/s/ Holly Koczot, attorney-in-fact	04/02/2026
	** 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)

SEC Form 4 filed by Shea Thomas Anthony