Organization and Business

Alumis Inc. (the “Company”) is a clinical stage biopharmaceutical company focused on identifying, acquiring, and accelerating the development and commercialization of transformative medicines for autoimmune disorders. The Company leverages its proprietary precision data analytics platform, biological insights, and a team of experts with deep experience in precision medicine drug discovery, development, and immunology, in its mission to create medicines that significantly improve the lives of patients by replacing broad immunosuppression with targeted therapies.

The Company was founded on January 29, 2021, as a Delaware corporation under the name FL2021-001, Inc. FL2021-001, Inc.’s name was changed to Esker Therapeutics, Inc. on March 8, 2021, and to Alumis Inc. on January 6, 2022. The Company is headquartered in South San Francisco, California.

As of June 30, 2026, the Company had two wholly owned subsidiaries, ACELYRIN, Inc. (“ACELYRIN”), a Delaware corporation incorporated on July 27, 2020 and its wholly owned subsidiary, WH2, LLC. Arrow Merger Sub, Inc. (“Merger Sub”), the Company’s wholly owned subsidiary incorporated in January 2025, was merged with and into ACELYRIN in May 2025.

ACELYRIN Merger

On February 6, 2025, the Company entered into an Agreement and Plan of Merger, and, on April 20, 2025, the Company entered into an Amendment to Agreement and Plan of Merger (collectively the “Merger Agreement”) with ACELYRIN and Merger Sub, a Delaware corporation and a direct wholly owned subsidiary of the Company. Under the terms of the Merger Agreement, Merger Sub merged with and into ACELYRIN, with ACELYRIN continuing as a direct wholly owned subsidiary of the Company (the “ACELYRIN Merger”). The Merger Agreement was approved by the disinterested directors on the Company’s board of directors and the board of directors of ACELYRIN and was approved by the stockholders of each company on May 13, 2025. On May 21, 2025, the Company completed the ACELYRIN Merger with ACELYRIN for a purchase consideration of $238.1 million that included the issuance of 48,653,549 shares of the Company’s common stock and the fair value of replacement awards attributable to pre-combination services, to acquire net assets with a fair value of $426.0 million. See Note 3 for additional information.

Public Offering of Common Stock

On January 7, 2026, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Morgan Stanley & Co. LLC, Leerink Partners LLC and Cantor Fitzgerald & Co. (“Cantor”) (collectively the “Underwriters”), relating to the issuance and sale in a public offering of 17,650,000 shares of the Company’s common stock at a price of $17.00 per share. In addition, the Company granted the Underwriters an option, exercisable for 30 days, to purchase up to 2,647,500 additional shares of common stock at the public offering price, less the underwriting discounts and commissions, which was exercised in full on January 8, 2026. On January 9, 2026, the offering closed and the Company received net proceeds of $324.4 million, after deducting underwriting discounts and commissions.

The offering was made pursuant to a shelf registration statement on Form S-3 (File No. 333-288510) that was filed with the U.S. Securities and Exchange Commission (“SEC”) on July 3, 2025 and declared effective by the SEC on August 19, 2025, and related prospectus and prospectus supplement thereunder.

Controlled Equity Offering^SM

On March 18, 2026, the Company entered into a Controlled Equity Offering^SM Sales Agreement (the “Sales Agreement”) with Cantor as sales agent, pursuant to which the Company may offer and sell, from time to time through Cantor, at its option, shares of its common stock having an aggregate offering price of up to $300.0 million (the “ATM Shares”). The sales of the ATM Shares will be made by any method permitted that is deemed to be an “at-the-market” equity offering as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the “Securities Act”), including sales made directly on or through the Nasdaq Global Select Market. The Company agreed to pay Cantor a commission of up to 3.0% of the aggregate gross proceeds from any ATM Shares sold by Cantor. As of June 30, 2026, no ATM Shares were sold under the Sales Agreement.

Liquidity

The Company has incurred negative operating cash flows and significant losses from operations since its inception. For the three and six months ended June 30, 2026 and 2025, the Company incurred net income (loss) of $(142.2) million, $59.3 million, $(235.3) million and $(39.6) million, respectively. Cash used in operating activities was $168.6 million and $186.7 million for the six months ended June 30, 2026 and 2025, respectively. As of June 30, 2026, the Company had an accumulated deficit of $1,137.2 million.

The Company has historically funded its operations primarily through the issuance of common stock, including in connection with the ACELYRIN Merger and the Company’s initial public offering (“IPO”) and a concurrent private placement transaction, the issuance of redeemable convertible preferred stock and convertible promissory notes in private placements, and, most recently, the public offering of common stock which closed on January 9, 2026, as well as cash payments received under the collaboration and license agreement (the “Kaken Collaboration Agreement”) with Kaken Pharmaceutical Co., Ltd. (“Kaken”). The Company expects to continue to incur substantial losses for the foreseeable future, and its ability to achieve and sustain profitability will depend on the successful development, approval, and commercialization of any product candidates it may develop, and on the achievement of sufficient revenue to support its cost structure. The Company may never achieve profitability and, unless and until it does, it will need to continue to raise additional capital. The Company believes that, based on its current operating plan, its existing cash, cash equivalents and marketable securities of $502.3 million as of June 30, 2026, will be sufficient to meet its operating and capital requirements for at least 12 months from the date of issuance of these unaudited condensed consolidated financial statements.

The Company will need to raise significant additional capital to fund ongoing research and development activities and maintain future operations. The Company’s management continuously monitors and, where necessary, may reduce its operating expenses in response to its clinical development progress and its ability and need to raise additional capital through a combination of public and private equity, debt financings, strategic alliances and licensing arrangements. For example, should any of the Company’s ongoing trials not meet its clinical development objectives, the Company may scale back or discontinue related activities and reallocate its working capital to extend its ability to meet its operating and capital requirements. The Company’s ability to access capital when needed is not assured and, if capital is not available to the Company when, and in the amounts, needed, on the terms which are favorable, the Company could be required to delay, scale back, or abandon some or all of its planned development programs and other operations, which could materially harm the Company’s business, financial condition and results of operations.