[144] Syndax Pharmaceuticals, Inc. SEC Filing

Rhea-AI Filing Summary

Form 144 notice for SNDX reports a proposed sale of 43,200 shares of common stock through Morgan Stanley Smith Barney LLC on 08/14/2025, with an aggregate market value of $581,040.00. The shares were acquired the same day by exercise of stock options and paid for in cash. The filing lists 86,141,862 shares outstanding, and there are no reported sales by the same person in the prior three months.

The notice confirms the seller represents they have no undisclosed material adverse information and follows Rule 144 procedures for the proposed sale.

Positive

• Full procedural disclosure of broker, number of shares, acquisition method, payment method, and aggregate value
• No sales in the prior three months reported, suggesting this is not part of a pattern of recent disposals

Negative

• Proposed sale filed under Rule 144 indicates restricted or previously unregistered shares are being sold, which may prompt monitoring by investors
• Seller identity not disclosed in the provided content, limiting context on whether the sale is by management, an option holder, or another party

Insights

Securities Analyst

TL;DR: A relatively small Rule 144 sale of newly exercised shares, executed through Morgan Stanley, appears routine and likely has limited market impact.

The filing documents a proposed sale of 43,200 shares valued at $581,040 executed the same day as exercise of stock options and paid in cash. Compared with the 86.14 million shares outstanding, the proposed sale represents roughly 0.05% of the outstanding share base, which is immaterial from a dilution or supply perspective. The absence of sales in the prior three months reduces the appearance of ongoing disposal, and use of a major broker indicates a standard orderly execution channel. Materiality for investors is low unless the seller is a high-profile insider or signals broader planned disposals, neither of which is stated in the filing.

Corporate Governance Specialist

TL;DR: The notice complies with Rule 144 disclosure norms; documentation of option exercise and immediate sale is routine governance activity.

The filer discloses acquisition by option exercise and immediate proposed sale, with payment in cash and broker details provided, meeting procedural expectations for publicly reporting restricted-share disposition. The representation that no undisclosed material adverse information exists is included, as required. There is no information about the seller's identity, insider status, or any trading plan dates, so governance implications are limited to procedural transparency rather than signaling management intent.

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
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	43200	581040.00	86141862	08/14/2025	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 *
Common	08/14/2025	Exercise of Stock Options	Issuer			43200	08/14/2025	Cash

* 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

Nothing to Report

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

What does the SNDX Form 144 disclose about the number of shares to be sold?

The filing discloses a proposed sale of 43,200 shares of common stock.

When is the approximate date of the proposed sale in the SNDX Form 144?

The filing lists the approximate date of sale as 08/14/2025.

How were the 43,200 SNDX shares acquired according to the Form 144?

The shares were acquired on 08/14/2025 by exercise of stock options and paid for in cash.

What is the aggregate market value and who is the broker for the proposed SNDX sale?

Aggregate market value is $581,040.00 and the broker is Morgan Stanley Smith Barney LLC.

How large is the proposed sale relative to SNDX outstanding shares?

The filing lists 86,141,862 shares outstanding; 43,200 shares represent roughly 0.05% of that total.