Solid Biosciences insider plans 48,913-share sale

Solid Biosciences insider Alexander Cumbo has filed a Form 144 indicating an intention to sell 48,913 shares of common stock through E*TRADE, with an aggregate market value of $315,079.69.

Rhea-AI Filing Summary

Solid Biosciences insider Alexander Cumbo has filed a Form 144 indicating an intention to sell 48,913 shares of common stock through E*TRADE, with an aggregate market value of $315,079.69. The planned sale date is listed as 02/04/2026, on the NASDAQ market, and the filing notes 82,569,192 shares outstanding.

The shares to be sold were acquired on 02/04/2026 through settlement of vested restricted stock units as compensation from the issuer. Over the past three months, Cumbo has sold 10,808 shares for $55,228.88 on 12/03/2025 and 80,258 shares for $516,612.72 on 02/02/2026.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does the Form 144 filing for Solid Biosciences (SLDB) disclose?

The filing discloses a planned insider sale of Solid Biosciences shares. Alexander Cumbo intends to sell 48,913 common shares through E*TRADE, with an aggregate market value of $315,079.69, and the planned sale is listed for February 4, 2026 on NASDAQ.

How many Solid Biosciences (SLDB) shares is the insider planning to sell?

The insider plans to sell 48,913 shares of Solid Biosciences common stock. The Form 144 states these shares have an aggregate market value of $315,079.69 and are expected to be sold on NASDAQ on or around February 4, 2026.

How were the Solid Biosciences (SLDB) shares in the Form 144 acquired?

The shares were acquired through vested restricted stock units. The filing explains that on February 4, 2026, 48,913 common shares were obtained from the issuer as compensation when restricted stock units settled, and those shares are now the subject of the planned sale.

What prior sales by the Solid Biosciences (SLDB) insider are reported?

The filing lists two prior sales in the past three months. Alexander Cumbo sold 10,808 shares for $55,228.88 on December 3, 2025, and 80,258 shares for $516,612.72 on February 2, 2026, both involving Solid Biosciences common stock.

Who is the broker for the planned Solid Biosciences (SLDB) share sale?

ETRADE Financial Corporation is the designated broker. The Form 144 lists E*TRADE Financial Corporation, located in Alpharetta, Georgia, as handling the planned sale of 48,913 Solid Biosciences common shares on the NASDAQ market.

How many Solid Biosciences (SLDB) shares are outstanding in this Form 144?

The Form 144 reports 82,569,192 shares outstanding. This figure provides context for the planned sale of 48,913 shares by insider Alexander Cumbo, as disclosed in the filing related to Solid Biosciences common stock.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 02/04/2026 - 07:44 PM Learn about SEC filing dates

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	0001685994
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Solid Biosciences Inc.
SEC File Number	001-38360
Address of Issuer	500 Rutherford Avenue Charlestown MASSACHUSETTS 02129
Phone	(617)-337-4680
Name of Person for Whose Account the Securities are To Be Sold	Cumbo Alexander
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	Officer
Relationship to Issuer	Director

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 Stock	ETRADE FINANCIAL CORPORATION 3 EDISON DRIVE ALPHARETTA GA 30005	48913	315079.69	82569192	02/04/2026	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 Stock	02/04/2026	Settlement of vested restricted stock units	Issuer			48913	02/04/2026	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
Cumbo Alexander C/O SOLID BIOSCIENCES INC. 500 Rutherford Ave Charlestown MA 02129	Common Stock	12/03/2025	10808	55228.88
Cumbo Alexander C/O SOLID BIOSCIENCES INC. 500 Rutherford Ave Charlestown MA 02129	Common Stock	02/02/2026	80258	516612.72

144: Remarks and Signature

Remarks	The sale reported on this Form 144 was made to cover witholding taxes following the vesting of previously granted performance stock units pursuant to a durable sale instruction letter adopted by Mr. Cumbo on August 18, 2024 effecting the sell-cover-election. The sale does not represent a discretionary trade by Mr. Cumbo.
Date of Notice	02/04/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	08/18/2024
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	/s/ Kimberly Cornwell as attorney-in-fact for Alexander Cumbo
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)