JONATHAN D. MARINER - 06 Jan 2026 Form 4 Insider Report for OneStream, Inc. (OS)

Role
Director
Signature
/s/ Holly Koczot, attorney-in-fact
Issuer symbol
OS
Transactions as of
06 Jan 2026
Net transactions value
-$185,436
Form type
4
Filing time
08 Jan 2026, 16:22:12 UTC
Previous filing
04 Dec 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
MARINER JONATHAN D Director C/O ONESTREAM, INC., 191 N. CHESTER STREET, BIRMINGHAM /s/ Holly Koczot, attorney-in-fact 08 Jan 2026 0001063663

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction OS Class A Common Stock Sale $54,724 -2,415 -16% $22.66 12,671 06 Jan 2026 Direct F1, F2, F3
transaction OS Class A Common Stock Sale $130,712 -5,541 -44% $23.59 7,130 06 Jan 2026 Direct F1, F3, F4
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

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).

Explanation of Responses:

Id Content
F1 The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on February 28, 2025.
F2 Represents the weighted average share price of an aggregate total of 2,415 shares sold in the price range of $22.375 to $23.275, inclusive, by the Reporting Person. The Reporting Person undertakes to provide upon request by the staff of the Securities and Exchange Commission, the issuer or any security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote in this Form 4.
F3 The shares reported include unvested restricted stock units.
F4 Represents the weighted average share price of an aggregate total of 5,541 shares sold in the price range of $23.555 to $23.635, inclusive, by the Reporting Person. The Reporting Person undertakes to provide upon request by the staff of the Securities and Exchange Commission, the issuer or any security holder of the issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote in this Form 4.