Alexander Cumbo - 29 Jan 2026 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
Issuer symbol
SLDB
Transactions as of
29 Jan 2026
Net transactions value
-$516,613
Form type
4
Filing time
02 Feb 2026, 20:16:31 UTC
Previous filing
04 Dec 2025
Next filing
06 Feb 2026
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 02 Feb 2026 0001685994

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction SLDB Common Stock Options Exercise +169,401 +208% 250,789 29 Jan 2026 Direct F1
transaction SLDB Common Stock Options Exercise +100,400 +40% 351,189 31 Jan 2026 Direct F2
transaction SLDB Common Stock Sale $516,613 -80,258 -23% $6.44 270,931 02 Feb 2026 Direct F3, F4

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 Performance Stock Units Options Exercise $0 -169,401 -100% $0.000000 0 29 Jan 2026 Common Stock 169,401 Direct F1, F5
transaction SLDB Employee Stock Option (Right to Buy) Award $0 +509,850 $0.000000 509,850 29 Jan 2026 Common Stock 509,850 $6.60 Direct F6
transaction SLDB Restricted Stock Units Award $0 +254,900 $0.000000 254,900 29 Jan 2026 Common Stock 254,900 Direct F2, F7
transaction SLDB Restricted Stock Units Options Exercise $0 -100,400 -25% $0.000000 301,200 31 Jan 2026 Common Stock 100,400 Direct F2, F8
* 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 performance stock unit ("PSUs") converts to common stock on a one-for-one basis.
F2 Each restricted stock unit ("RSUs") converts to common stock on a one-for-one basis.
F3 This sale was made to cover withholding taxes following the vesting of previously granted PSUs pursuant to a durable automatic sale 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 price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.295 to $6.580, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (4) to this Form.
F5 The PSUs were granted on June 11, 2024 and provide for the vesting of 25% of the target number of underlying RSUs granted upon the achievement of each of four independent performance milestones predetermined by the Board ("Performance Milestones"), subject to the grantee's continued service with the Company (the "Approval Conditions"). The Performance Milestones are tied to the achievement of certain business objectives, as certified by the Board on specified evaluation dates, and are non-market and non-financial in nature. The performance criteria specified for the first Performance Milestone was determined to be met on January 29, 2026 (the "2026 Grant Date") resulting in the vesting of the PSUs as to 25% of the underlying shares.
F6 This option was granted on the 2026 Grant Date and vests over four years, with 25% of the original number of shares vesting on the first anniversary of the 2026 Grant Date and 2.0833% of the original number of shares monthly thereafter until the fourth such anniversary.
F7 The RSUs were granted on the 2026 Grant Date and vest over four years, with 25% of the original number of shares vesting on each anniversary of the 2026 Grant Date until the fourth such anniversary.
F8 On January 31, 2025 (the "2025 Grant Date"), the reporting person was granted 401,600 RSUs, with 25% of the original number of shares vesting on each anniversary of the 2025 Grant Date until the fourth such anniversary.