Electra Therapeutics, Inc. (ETRA) is the subject of a Schedule 13G reporting 6,347,539 shares of common stock, or 10.1% of the class, as beneficially owned by Dr. Beth C. Seidenberg as of September 30, 2026. Westlake BioPartners Fund I, L.P. directly holds 3,527,136 shares (5.6%), and Westlake BioPartners Fund II, L.P. directly holds 2,820,403 shares (4.5%). Their general partners and Seidenberg may be deemed to have sole voting and dispositive power over the respective holdings. Each reporting person disclaims beneficial ownership except to the extent of a pecuniary interest or shares held of record.
Electra Therapeutics, Inc. is the issuer in a Schedule 13G reporting beneficial ownership by Redmile Group, LLC, Jeremy C. Green, and Redmile Biopharma Investments II, L.P. Redmile Group and Green each report beneficial ownership of 5,462,881 shares, or 8.7%; Redmile Biopharma Investments II directly owns 4,796,215 shares, or 7.6%.
The reported positions overlap: Redmile’s 5,462,881 shares include shares held by investment vehicles, including Redmile Biopharma Investments II. Redmile reports shared voting and dispositive power as investment manager, and Green as Redmile’s principal. Both disclaim beneficial ownership except to the extent of their pecuniary interest, if any. The percentages use 62,766,955 shares outstanding immediately after the initial public offering.
Electra Therapeutics, Inc. (ETRA) is the issuer of common stock for which LSP 7 Cooperatief U.A. and LSP 7 Management B.V. report beneficial ownership of 3,795,281 shares, or 6.0%, as of September 21, 2026. The reported position is based on 62,766,955 common shares outstanding as of that date. LSP 7 is the record holder, and LSP 7 Management B.V. is LSP 7’s sole director; both report shared voting and dispositive power over the shares. Managing directors Merijn Klaassen, Rene Kuijten and Joachim Rothe may also be deemed beneficial owners, and each disclaims beneficial ownership.
Electra Therapeutics, Inc. (ETRA) is the issuer in a Schedule 13D reporting OrbiMed entities’ beneficial ownership. OrbiMed Advisors LLC reported shared voting and dispositive power over 6,885,170 shares, or 11.0%. The reported holdings include 5,126,891 shares held by OPI VII and attributed to OrbiMed Capital GP VII LLC (8.2%), and 1,758,279 shares held by Genesis and attributed to OrbiMed Genesis GP LLC (2.8%). The ownership percentages use Electra’s 62,766,955 outstanding shares stated in its September 18, 2026 prospectus.
OPI VII and Genesis purchased 333,333 and 1,000,000 common shares, respectively, in the IPO at $15 per share. Certain holders have demand Form S-1 registration rights beginning 180 days after the IPO registration statement’s effective date, subject to the agreement. OPI VII, Genesis and Carl L. Gordon, an Electra director and OrbiMed Advisors member, agreed to lock-up restrictions, including on sales and registration demands, until 180 days after the final prospectus supplement, subject to limited exceptions.
Electra Therapeutics, Inc. director and 10% owner Gordon Carl L reported transactions involving securities held by OrbiMed Private Investments VII, LP and OrbiMed Genesis Master Fund, L.P. On September 21, 2026, at the closing of the issuer’s initial public offering, OrbiMed Private Investments VII, LP’s Series A preferred shares (2,002,310 shares), Series B preferred shares (1,087,934 shares) and Series C preferred shares (1,703,314 shares), and OrbiMed Genesis Master Fund, L.P.’s Series C preferred shares (758,279 shares), automatically converted one-for-one into Common Stock without further consideration.
The funds also purchased Common Stock in the IPO: 333,333 shares by OrbiMed Private Investments VII, LP and 1,000,000 shares by OrbiMed Genesis Master Fund, L.P., each at $15 per share. No Rule 10b5-1 plan is reported.
Electra Therapeutics, Inc. (ETRA) reports that OrbiMed Private Investments VII, LP converted 2,002,310 Series A, 1,087,934 Series B and 1,703,314 Series C preferred shares into common stock on September 21, 2026; OrbiMed Genesis Master Fund, L.P. converted 758,279 Series C preferred shares that day. Each preferred share automatically converted into one common share when Electra’s initial public offering closed, without further consideration. In the IPO, the funds also purchased 333,333 and 1,000,000 common shares, respectively, at $15 per share. OrbiMed Advisors LLC, OrbiMed Capital GP VII LLC and OrbiMed Genesis GP LLC, each identified as a director and ten-percent owner, jointly reported the transactions and disclaim beneficial ownership except to the extent of any pecuniary interest. OrbiMed Advisors exercises voting and investment power through a committee comprising Carl L. Gordon, W. Carter Neild and Geoffrey C. Hsu; each disclaims beneficial ownership of the fund-held shares. Carl L. Gordon was designated to serve on Electra’s board.
Electra Therapeutics, Inc. (ETRA) reports that investment funds affiliated with Westlake BioPartners are ten percent owners, with their positions reported on an initial Form 3. The funds’ common stock was acquired upon the automatic 1:1 conversion of redeemable preferred stock when Electra’s initial public offering closed, without further consideration.
The shares are held directly by Westlake BioPartners Fund I, L.P. and Westlake BioPartners Fund II, L.P., with Westlake BioPartners GP I, LLC and Westlake BioPartners GP II, LLC as their respective general partners. Beth Seidenberg, as sole managing director of both general partners, has voting and dispositive power over these shares but disclaims Section 16 beneficial ownership except to the extent of any pecuniary interest.
Electra Therapeutics, Inc. (symbol: ETRA) is the issuer of record for a Form 4 filing submitted to the SEC.
Electra Therapeutics, Inc. (ETRA) reported that director Nancy Stagliano converted all of her Series A Convertible Preferred Stock into Common Stock in connection with the closing of the company’s initial public offering. On September 21, 2026, 255,635 preferred shares automatically converted into 255,635 Common Shares on a 1-for-1 basis without further consideration, leaving her with 255,635 Common Shares held directly and no remaining Preferred Stock.
Electra Therapeutics, Inc. (symbol: ETRA) is the issuer of record for a Form 4 filing submitted to the SEC.