Alexander Cumbo - Dec 2, 2025 Form 4 Insider Report for Solid Biosciences Inc. (SLDB)

Role
President and CEO, Director
Signature
/s/ Kimberly Cornwell as attorney-in-fact for Alexander Cumbo
Stock symbol
SLDB
Transactions as of
Dec 2, 2025
Transactions value $
-$55,229
Form type
4
Date filed
12/4/2025, 04:20 PM
Previous filing
Aug 18, 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Cumbo Alexander President and CEO, Director C/O SOLID BIOSCIENCES INC., 500 RUTHERFORD AVENUE, THIRD FLOOR, CHARLESTOWN /s/ Kimberly Cornwell as attorney-in-fact for Alexander Cumbo 2025-12-04 0001685994

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction SLDB Common Stock Options Exercise +28.6K +45% 92.2K Dec 2, 2025 Direct F1, F2
transaction SLDB Common Stock Sale -$55.2K -10.8K -11.72% $5.11 81.4K Dec 3, 2025 Direct F3

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction SLDB Restricted Stock Units Options Exercise $0 -28.6K -50% $0.00 28.6K Dec 2, 2025 Common Stock 28.6K Direct F1, 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 Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock (the "RSUs").
F2 Includes 2,866 shares of common stock acquired under the Solid Biosciences Inc. Employee Stock Purchase Plan on May 30, 2025.
F3 This sale was made to cover withholding taxes following the vesting of the previously granted RSUs pursuant to a durable automatic sales instruction letter adopted by Mr. Cumbo on August 18, 2024 effecting the sell-to-cover election. The sale does not represent a discretionary trade by Mr. Cumbo.
F4 The RSUs were granted on December 2, 2022 (the "Grant Date") and vest over four years, with 25% of the original number of shares vesting on each anniversary of the Grant Date until the fourth such anniversary.