Sec Form 4 Filing - Colby Craig @ OneStream, Inc. - 2024-12-13

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 Colby Craig 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 X __ Officer (give title below) _____ Other (specify below) President (Last) (First) (Middle) C/O ONESTREAM, INC., 191 N. CHESTER STREET 3. Date of Earliest Transaction (MM/DD/YY) 12/13/2024 (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 12/13/2024 M 280,000 A $ 10.65 280,000 D Class A Common Stock 12/13/2024 S( 1 ) 208,194 D $ 29.47 ( 2 ) 71,806 D Class A Common Stock 12/13/2024 S( 1 ) 71,806 D $ 30.4 ( 3 ) 0 D Class A Common Stock 12/13/2024 C( 4 ) 167,821 A 167,821 I See Footnote ( 5 )

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 Stock Option (right to buy) $ 10.65 12/13/2024 M 140,000 ( 6 ) 12/04/2031 Class A Common Stock 140,000 $ 0 169,917 D Stock Option (right to buy) $ 10.65 12/13/2024 M 140,000 ( 7 ) 03/05/2033 Class A Common Stock 140,000 $ 0 368,753 D Common Units ( 8 ) 12/13/2024 C( 8 ) 167,821 ( 9 ) ( 9 ) Class D Common Stock 167,821 $ 0 7,304 I See Footnote ( 5 ) Class D Common Stock ( 8 ) 12/13/2024 C( 8 ) 167,821 ( 10 ) ( 10 ) Class A Common Stock 167,821 $ 0 167,821 I See Footnote ( 5 ) Class D Common Stock ( 4 ) 12/13/2024 C( 4 ) 167,821 ( 10 ) ( 10 ) Class A Common Stock 167,821 $ 0 0 I See Footnote ( 5 ) Class D Common Stock ( 10 ) ( 10 ) ( 10 ) Class A Common Stock 6,894,697 6,894,697 D Class D Common Stock ( 10 ) ( 10 ) ( 10 ) Class A Common Stock 3,353,799 3,353,799 I See Footnote ( 11 ) Class D Common Stock ( 10 ) ( 10 ) ( 10 ) Class A Common Stock 1,675,503 1,675,503 I See Footnote ( 12 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Colby Craig C/O ONESTREAM, INC. 191 N. CHESTER STREET BIRMINGHAM, MI48009 X President Signatures /s/ Holly Koczot, attorney-in-fact 12/17/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 13, 2024. ( 2 )Represents the weighted average share price of an aggregate total of 208,194 shares sold in the price range of $29.06 to $30.04 by the Reporting Person. The Reporting Person undertakes to provide upon request by the Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price. ( 3 )Represents the weighted average share price of an aggregate total of 71,806 shares sold in the price range of $30.07 to $30.77 by the Reporting Person. The Reporting Person undertakes to provide upon request by the Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price. ( 4 )The Class A Common Stock was acquired upon the conversion, at the holder's election, of Class D Common Stock held by the holder on a 1:1 basis. ( 5 )The shares are held of record by CCICU Corp. CCICU Corp. is a subchapter S corporation of which the Reporting Person is the sole owner and maintains control. ( 6 )One-fourth of the shares subject to the option vested on February 15, 2023, 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. ( 7 )One-fourth of the shares subject to the option vested on February 15, 2024, 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. ( 8 )On December 13, 2024, the holder redeemed 167,821 Common Units of OneStream Software LLC, and 167,821 shares of the holder's Class C Common Stock were cancelled, in exchange for 167,821 shares of Class D Common Stock. ( 9 )The Common Units may be redeemed by the holder for shares of Class D Common Stock on a 1:1 basis, and an equal number of the holder's shares of Class C Common Stock (which have no economic rights) will be cancelled in connection with the redemption. The Common Units have no expiration date. ( 10 )The Class D Common Stock is 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 upon the earlier of (i) any transfer, whether or not for value, except for certain transfers exempted by the Issuer's amended and restated certificate of incorporation, (ii) death or incapacity (if the holder is a natural person), and (iii) the first trading day following the seventh anniversary of the Issuer's initial public offering. ( 11 )The shares are held of record by the 2023 Trust for Kelly and Katharine Colby and Their Descendants dated April 27, 2023, of which the Reporting Person serves as the investment trustee. ( 12 )The shares are held of record by the Trust for Jake A. Colby and Descendants dated December 28, 2019, of which the Reporting Person serves as the investment trustee.

Remarks: Since the date of the Reporting Person's last Form 4, the Reporting Person resigned as trustee of the 2023 Trust for Kristen M. Colby dated April 27, 2023. Accordingly, the Reporting Person no longer has investment control over, and therefore is not deemed to beneficially own, any of the shares held by the 2023 Trust for Kristen M. Colby dated April 27, 2023.

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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