Solid Biosciences Inc. received an updated ownership disclosure from Adage Capital affiliates. Adage Capital Management, L.P., together with Robert Atchinson and Phillip Gross, reports beneficial ownership of 1,400,000 shares of Solid Biosciences common stock, representing 1.80% of the outstanding shares as of October 29, 2025.
The shares are held through Adage Capital Partners, L.P., with shared voting and dispositive power and no sole voting or dispositive power reported. The filing is on a passive Schedule 13G/A basis, and the reporting group confirms the position is held in the ordinary course of business and not to change or influence control of the company.
Positive
None.
Negative
None.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 2)
Solid Biosciences Inc.
(Name of Issuer)
Common Stock $0.001 par value per share
(Title of Class of Securities)
83422E204
(CUSIP Number)
12/31/2025
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
SCHEDULE 13G
CUSIP No.
83422E204
1
Names of Reporting Persons
Adage Capital Management, L.P.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,400,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,400,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,400,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
1.80 %
12
Type of Reporting Person (See Instructions)
IA, PN
SCHEDULE 13G
CUSIP No.
83422E204
1
Names of Reporting Persons
Robert Atchinson
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,400,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,400,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,400,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
1.80 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
CUSIP No.
83422E204
1
Names of Reporting Persons
Phillip Gross
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,400,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,400,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,400,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
1.80 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Solid Biosciences Inc.
(b)
Address of issuer's principal executive offices:
500 Rutherford Avenue, 3rd Floor, Charlestown, MA 02129
Item 2.
(a)
Name of person filing:
This statement is filed by:
(i) Adage Capital Management, L.P., a Delaware limited partnership ("ACM"), as the investment manager of Adage Capital Partners, L.P., a Delaware limited partnership ("ACP"), with respect to the shares of common stock, par value $0.001 per share ("Common Stock"), of Solid Biosciences, Inc., a Delaware corporation (the "Company"), directly held by ACP;
(ii) Robert Atchinson ("Mr. Atchinson"), as (1) managing member of Adage Capital Advisors, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACA"), managing member of Adage Capital Partners GP, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACPGP"), general partner of ACP and (2) managing member of Adage Capital Partners LLC, a Delaware limited liability company ("ACPLLC"), general partner of ACM, with respect to the shares of Common Stock directly held by ACP; and
(iii) Phillip Gross ("Mr. Gross"), as (1) managing member of ACA, managing member of ACPGP and (2) managing member of ACPLLC, general partner of ACM, with respect to the shares of Common Stock directly held by ACP.
The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party.
The filing of this statement should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of the securities reported herein.
(b)
Address or principal business office or, if none, residence:
The address of the business office of each of the Reporting Persons is 200 Clarendon Street, 52nd Floor, Boston, Massachusetts 02116.
(c)
Citizenship:
ACM is a limited partnership organized under the laws of the State of Delaware. Messrs. Gross and Atchinson are citizens of the United States.
(d)
Title of class of securities:
Common Stock $0.001 par value per share
(e)
CUSIP No.:
83422E204
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
The percentage set forth in this Schedule 13G is calculated based upon an aggregate of 77,910,239 shares of Common Stock outstanding as of October 29, 2025, as reported in the Company's Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2025, filed with the Securities and Exchange Commission on November 3, 2025.
(b)
Percent of class:
1.80%
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(ii) Shared power to vote or to direct the vote:
The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iii) Sole power to dispose or to direct the disposition of:
The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iv) Shared power to dispose or to direct the disposition of:
The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
Item 5.
Ownership of 5 Percent or Less of a Class.
Ownership of 5 percent or less of a class
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
See Item 2(a).
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
Adage Capital Management, L.P.
Signature:
/s/ Robert Atchinson
Name/Title:
By: Adage Capital Partners LLC, its General Partner, By: Robert Atchinson, its Managing Member
What stake in Solid Biosciences (SLDB) does Adage Capital report?
Adage Capital entities report beneficial ownership of 1,400,000 Solid Biosciences common shares, equal to 1.80% of the company’s outstanding stock as of October 29, 2025. This reflects a relatively small, non-controlling position in the company.
Which entities are the reporting persons in this Solid Biosciences (SLDB) Schedule 13G/A?
The reporting persons are Adage Capital Management, L.P., and individuals Robert Atchinson and Phillip Gross. Adage Capital acts as investment manager to Adage Capital Partners, L.P., which directly holds the Solid Biosciences shares reported in this filing.
How much voting power does Adage have over Solid Biosciences (SLDB) shares?
The reporting persons disclose shared voting power over 1,400,000 shares and no sole voting power. They also report shared dispositive power over the same number of shares, indicating decisions are made collectively through the Adage-managed investment entity.
Is Adage’s Solid Biosciences (SLDB) position considered passive or activist?
The holders certify the shares were acquired and are held in the ordinary course of business and not for changing or influencing control of Solid Biosciences. This indicates a passive investment intent under the Schedule 13G framework.
Why does the Solid Biosciences (SLDB) filing mention ownership of 5 percent or less?
Item 5 of the filing notes that the reporting persons own 5 percent or less of the class. Their 1.80% stake confirms they are below major-holder thresholds, signaling a smaller institutional position rather than a large controlling or blocking stake.
Who directly holds the Solid Biosciences (SLDB) shares reported by Adage?
The shares are directly held by Adage Capital Partners, L.P., a Delaware limited partnership. Adage Capital Management, L.P. serves as investment manager, while Robert Atchinson and Phillip Gross are managing members of related general partner and advisory entities overseeing this interest.
