[Form 4] Solid Biosciences Inc. Insider Trading Activity

Rhea-AI Filing Summary

Form 4 highlights: On 07/06/2025, Solid Biosciences Inc. (SLDB) director Ian F. Smith acquired 4,573 common shares through the mandatory conversion (Code M) of previously granted restricted stock units (RSUs). The RSUs, issued on 01/06/2025, vest in four equal quarterly tranches and convert to common stock on a 1-for-1 basis. Following the transaction, Smith now directly owns 122,119 common shares and retains 9,146 unvested RSUs. The RSUs will accelerate in full if the Executive Chair Agreement terminates early or upon a change in control of the company. No shares were sold, suggesting continued insider exposure to SLDB’s equity. The filing was signed on 07/08/2025.

Positive

• Director increased direct ownership by 4,573 shares, bringing total holdings to 122,119 shares with no dispositions.
• No shares were sold, which can be read as a mild confidence signal from the insider.

Negative

• None.

Insights

Securities Analyst

TL;DR Small RSU conversion adds 4,573 shares; no sale—neutral to mildly positive insider signal.

The transaction is routine in size and structure: 4,573 RSUs vested and converted, costing $0 and increasing the director’s direct holdings to 122,119 shares. Because no stock was sold, the filing can be interpreted as a modest vote of confidence, but the share count is not large enough to materially affect ownership percentages or governance dynamics. Acceleration clauses tied to a change in control are standard and do not imply any pending corporate action. Overall impact on valuation or float is negligible.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a 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). See Instruction 10.

1. Name and Address of Reporting Person^*

SMITH IAN F

(Last) (First) (Middle)

C/O SOLID BIOSCIENCES INC.

500 RUTHERFORD AVENUE, THIRD FLOOR

(Street)

CHARLESTOWN MA 02129

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Solid Biosciences Inc. [ SLDB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
07/06/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	07/06/2025		M		4,573	A	(1)	122,119	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units	(1)	07/06/2025		M			4,573	(2)	(2)	Common Stock	4,573	$0.00	9,146	D

Explanation of Responses:

1. Restricted stock units convert to common stock on a one-for-one basis.

2. The restricted stock units were granted on January 6, 2025 (the "Grant Date") and vest in equal quarterly installments beginning three months from the Grant Date, with the final installment vesting the date that is 12 months from the Grant Date; provided that in the event of the early termination of the Third Amendment to Executive Chair Agreement between the Issuer and the reporting person (the "Smith Agreement") prior to the expiration of the Term (as defined in the Smith Agreement) and/or a change in control of the Issuer, the restricted stock units shall accelerate in full.

	/s/ David Tyronne Howton as attorney-in-fact for Ian F. Smith	07/08/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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FAQ

How many SLDB shares did Director Ian F. Smith acquire?

He acquired 4,573 common shares via RSU conversion on 07/06/2025.

What is Ian F. Smith’s total direct ownership after the transaction?

He now directly holds 122,119 common shares of Solid Biosciences Inc.

Were any shares sold in this Form 4 filing for SLDB?

No. The filing reports only an acquisition; no dispositions occurred.

How many RSUs remain outstanding for the director?

After conversion, 9,146 RSUs are still outstanding.

What triggers accelerated vesting of these RSUs?

Accelerated vesting occurs if the Executive Chair Agreement ends early or if there is a change in control of SLDB.