Bain Capital Life Sciences Investors, LLC - 19 Feb 2025 Form 4 Insider Report for Solid Biosciences Inc. (SLDB)

Footnote F1

On February 19, 2025, BCLS II Investco, LP ("BCLS II Investco") purchased 1,000,000 shares of the Issuer's common stock and a pre-funded warrant to purchase 6,444,170 shares of the Issuer's common stock at a purchase price of $4.03 and $4.029, respectively, in an underwritten public offering (the "February 2025 Underwritten Offering").

Footnote F2

The pre-funded warrant cannot be exercised if, as a result of such exercise, the holder, together with its affiliates and any other persons whose beneficial ownership would be aggregated with the holder for purposes of Section 13(d) of the Act, would beneficially own more than 9.99% of the total number of shares of the Issuer's common stock then outstanding immediately following such exercise.

Footnote F3

The pre-funded warrant does not expire.

Footnote F4

Represents 528,660 shares of the Issuer's common stock held directly by BCLS SB Investco, LP ("BCLS SB"), 267,257 shares of the Issuer's common stock held directly by Bain Capital Life Sciences Fund II, L.P. ("BCLS Fund II"), 3,301,955 shares of the Issuer's common stock held directly by BCLS II Investco, 904,160 shares of the Issuer's common stock held directly by BCLS II Equity Opportunities, LP ("BCLS II Equity") and 32,550 shares of the Issuer's common stock held directly by BCIP Life Sciences Associates, LP ("BCIPLS" and, together with BCLS II Investco, BCLS SB, BCLS Fund II and BCLS II Equity, the "Bain Capital Life Sciences Entities"), after giving effect to the closing of the February 2025 Underwritten Offering.

Footnote F5

Represents a pre-funded warrant to purchase 6,444,170 shares of the Issuer's common stock held directly by BCLS II Investco, after giving effect to the closing of the February 2025 Underwritten Offering.

Footnote F6

Bain Capital Life Sciences Partners, LP ("BCLSP") is the general partner of BCLS SB. As a result, BCLSP may be deemed to share voting and dispositive power with respect to the securities held by BCLS SB. BCLSP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

Footnote F7

Bain Capital Life Sciences Investors II, LLC ("BCLSI II") is the general partner of BCLS Fund II. As a result, BCLSI II may be deemed to share voting and dispositive power with respect to the securities held by BCLS Fund II. BCLSI II disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

Footnote F8

BCLS II Investco (GP), LLC ("BCLS II Investco GP"), whose managing member is BCLS Fund II, is the general partner of BCLS II Investco. As a result, each of BCLSI II, BCLS Fund II and BCLS II Investco GP may be deemed to share voting and dispositive power with respect to the securities held by BCLS II Investco. Each of BCLSI II, BCLS Fund II and BCLS II Investco GP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

Footnote F9

BCLS II Equity Opportunities GP, LLC ("BCLS II Equity GP"), whose manager is BCLS Fund II, is the general partner of BCLS II Equity. As a result, each of BCLSI II, BCLS Fund II and BCLS II Equity GP may be deemed to share voting and dispositive power with respect to the securities held by BCLS II Equity. Each of BCLSI II, BCLS Fund II and BCLS II Equity GP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

Footnote F10

Boylston Coinvestors, LLC is the general partner of BCIPLS.

Footnote F11

Bain Capital Life Sciences Investors, LLC ("BCLSI") (i) is the general partner of BCLSP, (ii) is the manager of BCLSI II and (iii) governs the investment strategy and decision-making process with respect to investments held by BCIPLS. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Life Sciences Entities. BCLSI disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.