OS Insider Files Form 144 to Sell 8,943 Shares After Vesting

Rhea-AI Filing Summary

OneStream, Inc. (OS) filed a Form 144 notifying the proposed sale of 8,943 Class A shares to be executed through Fidelity Brokerage Services on or about 09/15/2025 at an aggregate market value of $170,185.29. The shares were acquired on 09/10/2025 upon restricted stock vesting and are described as compensation for the holder.

The filing lists three prior Class A sales by the same person in the past three months: 9,354 shares on 06/16/2025 for $260,976.60, 25,000 shares on 06/25/2025 for $669,250.00, and 25,000 shares on 07/25/2025 for $625,000.00. Total outstanding Class A shares reported: 88,136,155.

Positive

• Disclosure compliance: The filer provided a Form 144 with broker, share count, and acquisition details consistent with Rule 144 requirements.
• Source of shares disclosed: Shares were acquired via restricted stock vesting and payment is labeled compensation.

Negative

• Insider sales activity: The filer reported substantial prior sales in the past three months totaling 59,354 shares for $1,555,226.60, which may signal ongoing insider monetization.

Insights

Securities Analyst

TL;DR: Insider plans a small sale after recent larger disposals; transaction stems from restricted stock vesting as compensation.

The Form 144 documents a proposed sale of 8,943 Class A shares valued at $170,185.29, acquired by restricted stock vesting on 09/10/2025 and designated as compensation. Recent reported disposals by the same person include three sales totaling 59,354 shares in June–July 2025 with combined gross proceeds of $1,555,226.60. Relative to the reported 88.1 million outstanding Class A shares, the current notice is immaterial to share count but is relevant for disclosure and insider liquidity transparency.

Corporate Governance Expert

TL;DR: Filing meets disclosure obligations; indicates routine insider monetization of vested compensation.

The notice shows the seller representing no undisclosed material information and identifies execution through a registered broker. The source of the shares is restricted stock vesting with payment classified as compensation, which aligns with typical insider reporting. The filing documents recent sales over the past three months, supporting transparency around insider transactions and compliance with Rule 144 reporting requirements.

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK
Filer CCC
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

Name of Person for Whose Account the Securities are To Be Sold

See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.

Relationship to Issuer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Class A	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	8943	170185.29	88136155	09/15/2025	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Class A	09/10/2025	Restricted Stock Vesting	Issuer			8943	09/10/2025	Compensation

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
William A. Koefoed Jr 191 N. Chester Street Birmingham MI 48009	Class A	06/16/2025	9354	260976.60
William A. Koefoed Jr 191 N. Chester Street Birmingham MI 48009	Class A	06/25/2025	25000	669250.00
William A. Koefoed Jr 191 N. Chester Street Birmingham MI 48009	Class A	07/25/2025	25000	625000.00

144: Remarks and Signature

Remarks

Date of Notice

Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1

ATTENTION:

The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.

Signature

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)

FAQ

How many OneStream (OS) Class A shares does the Form 144 propose to sell?

The notice proposes the sale of 8,943 Class A shares with an aggregate market value of $170,185.29.

When were the shares acquired and what was the nature of acquisition?

The shares were acquired on 09/10/2025 through restricted stock vesting and the payment is listed as compensation.

Through which broker will the proposed sale be executed?

The proposed sale is to be executed through Fidelity Brokerage Services LLC on or about 09/15/2025.

What insider sales by the same person occurred in the past three months?

Three prior Class A sales are listed: 9,354 shares on 06/16/2025 for $260,976.60, 25,000 shares on 06/25/2025 for $669,250.00, and 25,000 shares on 07/25/2025 for $625,000.00.

How many Class A shares are outstanding according to the filing?

The filing reports 88,136,155 Class A shares outstanding.