Aktis Oncology, Inc. filings document the company’s transition into a Nasdaq-listed public oncology issuer and its disclosure obligations as a clinical-stage oncology company. S-1/A registration materials and current reports describe its targeted radiopharmaceutical pipeline, including AKY-1189 and AKY-2519, the miniprotein radioconjugate platform, collaboration revenue, and operating results.
Its filings also cover post-IPO governance and capital-structure matters, including amended charter provisions, authorized common, Class A common and undesignated preferred stock, classified board provisions, director appointments, board committee structure, financial-results exhibits, and registered common stock under the AKTS symbol.
Aktis Oncology’s major venture backers report large post-IPO stakes. A group of MPM BioImpact-affiliated funds and individuals together report beneficial ownership positions in Aktis Oncology common stock, with Ansbert Gadicke associated with 10,260,064 shares, representing 19.3% of the company’s 53,296,950 shares outstanding as of the IPO prospectus. Luke Evnin is associated with 5,082,483 shares, or 9.5%, and Todd Foley with 4,237,506 shares, or 8.0%, including 2,103 stock options exercisable within 60 days.
The MPM entities are venture capital investors and acquired stakes through the IPO and automatic conversion of preferred stock. On January 12, 2026, they bought an aggregate 1,112,777 shares at $18.00 per share, for a total of $20,029,986, and also received 8,805,578 shares via preferred stock conversion at the IPO closing. The investors describe their holdings as for investment purposes, while retaining flexibility to buy or sell shares over time, and hold registration rights and are party to 180‑day IPO lock-up agreements.
EcoR1 Capital has disclosed a significant new stake in Aktis Oncology, Inc. following the company’s IPO. EcoR1 Capital, LLC reports beneficial ownership of 4,824,469 shares of common stock, representing 9.1% of the class, while its fund EcoR1 Capital Fund Qualified, L.P. holds 4,348,658 shares, or 8.2%. Oleg Nodelman, EcoR1’s manager and an Aktis director, is deemed to beneficially own 4,862,335 shares, or 9.1%, including 37,866 shares issuable under stock options granted for his board service.
The position was built through purchases of Series A and Series B redeemable convertible preferred stock totaling $32,800,000, which converted at IPO into common and Class A common shares, plus an additional 2,222,222 common shares bought in the IPO for $39,999,996. The funds also hold 1,051,412 Class A common shares that are convertible into common stock but subject to a 4.99% beneficial ownership cap. EcoR1 and Nodelman have agreed to a 180-day lock-up on sales after the offering but state they may buy or sell shares, convert Class A common stock, or use hedging strategies over time.
Eli Lilly and Company filed a Schedule 13D disclosing an 11.9% ownership stake in Aktis Oncology, Inc. following Aktis’s initial public offering. Lilly reports beneficial ownership of 6,344,114 shares of Aktis common stock, based on 53,296,950 shares outstanding after the IPO and full exercise of the underwriters’ option.
The stake comes from the conversion of preferred stock acquired for $12.0 million into 788,559 common shares at the IPO closing and the purchase of 5,555,555 shares in the IPO at $18.00 per share for about $100.0 million in cash. Lilly states it acquired the position for investment purposes, may buy or sell shares over time, and is party to an Investors’ Rights Agreement providing registration rights, as well as a 180‑day IPO lock-up restricting sales through mid‑2026.
Aktis Oncology director and 10% owner Todd Foley reported indirect changes in ownership tied to the company’s initial public offering. Investment funds affiliated with MPM converted preferred stock into common stock and also bought additional shares.
On January 12, 2026, 2,272,727 Series Seed, 10,227,273 Series A and 2,727,273 Series B redeemable convertible preferred shares automatically converted into 597,391, 2,688,270 and 716,872 shares of common stock, respectively, at a 3.8044-for-1 ratio with no additional payment upon the IPO closing. The affiliated funds also purchased 232,870 common shares at $18 each, bringing their indirect common stock holdings to 4,235,403 shares.
The shares are held across MPM BioVentures 2018, L.P., MPM BioVentures 2018 (B), L.P. and MPM Asset Management Investors BV2018 LLC, and the reporting persons disclaim beneficial ownership beyond their pecuniary interest.
Aktis Oncology large shareholders affiliated with MPM BioVentures 2018 reported major equity changes tied to the company’s initial public offering. On January 12, 2026, entities in the group converted Series Seed, Series A and Series B Redeemable Convertible Preferred Stock into common shares at a 3.8044-for-1 ratio, resulting in 1,314,262, 5,914,197 and 1,577,119 shares of common stock from each series, respectively. The group also reported purchasing an additional 1,112,777 common shares at $18 per share. Following these transactions, the reporting entities indirectly held a total of 10,260,064 Aktis Oncology common shares spread across several investment funds. The reporting persons state that they disclaim beneficial ownership except to the extent of their pecuniary interest.
Aktis Oncology insider funds reported major share conversions and a purchase tied to its initial public offering. On January 12, 2026, investment entities linked to MPM converted 5,000,000 Series Seed, 22,500,000 Series A and 6,000,000 Series B Redeemable Convertible Preferred Stock into common shares at a 3.8044‑for‑1 rate, issuing 1,314,262, 5,914,197 and 1,577,119 common shares, respectively.
These common shares are held across multiple MPM vehicles, including MPM Asset Management LLC, several MPM BioVentures funds, MPM Oncology funds and Oncology Impact Private Investment Fund 2, L.P. The MPM‑affiliated funds also purchased 1,112,777 shares of Aktis Oncology common stock at $18 per share, bringing their indirectly held common stock to 10,260,064 shares. The reporting persons disclaim beneficial ownership of these securities except to the extent of their pecuniary interest.
Aktis Oncology, Inc. received a large shareholder disclosure showing that Vida Ventures funds and related entities, together with director Helen Kim, beneficially own about 10.9% of the company’s common stock, based on 53,296,950 shares outstanding. Vida Ventures II, LLC holds 5,671,825 shares (10.6% of the class) and Vida Ventures II-A, LLC holds 157,387 shares (0.3%), all managed by VV Manager II, LLC.
The filing explains that these positions were built through multiple preferred stock investments in 2021–2024 that converted to common stock at the IPO, plus purchases in the offering at $18.00 per share. Helen Kim is a board member and holds 2,103 shares subject to stock options exercisable within 60 days, in addition to the Vida-related holdings. Vida II, Vida II-A and Ms. Kim have entered into 180-day lock-up agreements and hold registration and other rights under an investors’ rights agreement, while stating they may adjust their stake over time for general investment purposes.
Aktis Oncology, Inc. director-affiliated investment funds advised by EcoR1 Capital, LLC reported a series of equity transactions in connection with the company’s initial public offering. On January 12, 2026, shares of Series A and Series B Redeemable Convertible Preferred Stock held by EcoR1-advised funds converted into Common Stock and Class A Common Stock on a 3.8044-for-1 basis immediately before the IPO closing for no additional consideration.
The filing also shows the EcoR1-advised funds purchased 2,077,779 and 144,443 shares of Common Stock at $18 per share. Each share of Class A Common Stock is convertible into one share of Common Stock at the holder’s election for no additional consideration, subject to a 4.99% beneficial ownership limitation. The securities are held by EcoR1 Capital Fund Qualified, L.P., EcoR1 Capital Fund, L.P., and EcoR1 Venture Opportunity Fund, L.P.; EcoR1 and Oleg Nodelman may be deemed to indirectly beneficially own them but disclaim beneficial ownership beyond their pecuniary interests.
Vida Ventures II, LLC and Vida Ventures II-A, LLC, both 10% owners of Aktis Oncology, Inc., reported multiple transactions dated 01/12/2026. Series A and Series B Redeemable Convertible Preferred Stock automatically converted into Common Stock on a 3.8044-for-1 basis immediately before the closing of Aktis Oncology’s initial public offering, with no additional consideration paid.
Following these conversions and open-market purchases, Vida Ventures II, LLC indirectly held 5,671,825 shares of Common Stock after acquiring 4,859,370 shares through conversion and buying 812,455 shares at $18 per share. Vida Ventures II-A, LLC indirectly held 157,387 shares of Common Stock after receiving 134,842 shares through conversion and purchasing 22,545 shares at $18 per share.
Aktis Oncology, Inc. director and 10% owner Kim Helen Susan reported indirect ownership changes tied to the company’s initial public offering. Investment entities Vida Ventures II, LLC and Vida Ventures II-A, LLC converted their Series A and Series B Redeemable Convertible Preferred Stock into Common Stock on a 3.8044-for-1 basis immediately before the IPO closing, with no additional cash paid. Following these conversions and additional purchases at $18 per share on the same date, Vida Ventures II, LLC held 5,671,825 shares of Common Stock and Vida Ventures II-A, LLC held 157,387 shares, over which various Vida Ventures entities and committee members, including the reporting person, may be deemed to share voting and investment power, subject to pecuniary-interest disclaimers.