Sec Form 4 Filing - Fugere Peter @ OneStream, Inc. - 2024-07-25

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Fugere Peter 2. Issuer Name and Ticker or Trading Symbol OneStream, Inc. [ OS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O ONESTREAM, INC., 191 N. CHESTER STREET 3. Date of Earliest Transaction (MM/DD/YY) 07/25/2024 (Street) BIRMINGHAM, MI48009 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 Class A Common Stock 07/25/2024 S 175,831 D $ 18.85 0 D Class A Common Stock 07/25/2024 S 37,699 D $ 18.85 0 I The Fugere Grantor Retained Annuity Trust 1 ( 1 ) Class A Common Stock 07/25/2024 S 39,584 D $ 18.85 0 I The Fugere Grantor Retained Annuity Trust 2 ( 1 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 Common Units $ 0 07/25/2024 S( 2 ) 65,217 ( 3 ) ( 3 ) Class A Common Stock 65,217 $ 18.85 273,696 I Fugere Holding LLC ( 4 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Fugere Peter C/O ONESTREAM, INC. 191 N. CHESTER STREET BIRMINGHAM, MI48009 X Signatures /s/ Peter Fugere 07/29/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Mr. Fugere and Debra Silberstein serve together as the co-trustees for The Fugere Grantor Retained Annuity Trust 1 and The Fugere Grantor Retained Annuity Trust 2, each has shared voting and investment power over these shares. ( 2 )As described in the Issuer's prospectus dated July 23, 2024, filed with the Securities and Exchange Commission on July 24, 2024, the Issuer used a portion of the net proceeds from its initial public offering of Class A Common Stock to purchase Common Units of OneStream Software LLC held by certain of OneStream Software LLC's pre-IPO equityholders, including the Reporting Person, at a price of $18.85 per Common Unit. For every Common Unit sold, the Reporting Person also forfeited one share of the Issuer's Class C Common Stock, which was canceled for no consideration. ( 3 )The Common Units may be redeemed by the Reporting Person for shares of Class D Common Stock on a 1:1 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. The Class D Common Stock is in turn convertible at any time, at the holder's election, into Class A Common Stock on a 1:1 basis. Each outstanding share of Class D Common Stock will automatically convert into one share of Class A Common Stock on the first trading day following the seventh anniversary of the Issuer's initial public offering. The Common Units have no expiration date. ( 4 )Mr. Fugere has sole voting and investment power over the shares held by Fugere Holding LLC.

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).

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