Transaction Details

Footnotes

On February 6, 2025, ACELYRIN, Inc., a Delaware corporation (the "Company"), entered into an Agreement and Plan of Merger (as amended on April 20, 2025, the "Merger Agreement") with Alumis, Inc., a Delaware corporation ("Parent"), and Arrow Merger Sub, Inc., a Delaware corporation and wholly owned subsidiary of Parent ("Merger Sub"). Pursuant to the Merger Agreement, on May 21, 2025, Merger Sub merged with and into the Company (the "Merger"), with the Company surviving as a wholly owned subsidiary of Parent. At the effective time of the Merger (the "Effective Time"), each share of common stock, par value $0.00001 per share, of the Company issued and outstanding was converted into the right to receive 0.4814 (the "Exchange Ratio") shares of voting common stock of Parent, par value $0.0001 per share ("Parent Common Stock"), and cash in lieu of any fractional shares. | (Continued from Footnote 1) Pursuant to the Merger Agreement, at the Effective Time, each outstanding and unvested restricted stock unit ("RSU") immediately prior to the Effective Time was assumed by Parent and converted into an RSU award with respect to a number of shares of Parent Common Stock equal to (i) the total number of shares subject to the RSU immediately prior to the Effective Time multiplied by (ii) the Exchange Ratio, with any fractional shares rounded down to the nearest whole share. At the Effective Time, each outstanding and vested RSU immediately prior the Effective Time, including any RSU that became vested as a result of the Merger, was cancelled and converted into the right to receive the number of shares of Parent Common Stock equal to (i) the total number of shares subject to the RSU immediately prior to the Effective Time multiplied by (ii) the Exchange Ratio, with any fractional shares rounded down to the nearest whole share. | (Continued from Footnote 2) At the Effective Time, each outstanding performance-based restricted stock unit ("PSU") award that was outstanding and unvested immediately prior to the Effective Time was deemed earned at 100% of the target level of performance and converted into an RSU award with respect to a number of shares of Parent Common Stock equal to (i) the target number of shares subject to the PSU immediately prior to the Effective Time multiplied by (ii) the Exchange Ratio, with any fractional shares rounded down to the nearest whole share. | 1/4 of the shares subject to the option vested on May 9, 2025, and 1/48 of the shares subject to the option vests in equal monthly installments thereafter, subject to the Reporting Person's continued service. | Pursuant to the Merger Agreement, at the Effective Time each stock option that was outstanding and unexercised immediately prior to the Effective Time with a per share exercise price of $18.00 or less was assumed by Parent and converted into an option to purchase a number of shares of Parent Common Stock equal to (i) the number of shares subject to the option immediately prior to the Effective Time, multiplied by (ii) the Exchange Ratio, with any fractional shares rounded down to the nearest whole share, which stock option shall have an exercise price equal to (i) the per share exercise price for shares subject to the corresponding Company stock option immediately prior to the Effective Time, divided by (ii) the Exchange Ratio, rounded up to the nearest whole cent. | 1/4 of the shares subject to the option vested on January 9, 2025, and 1/48 of the shares subject to the option vest in equal monthly installments thereafter, subject to the Reporting Person's continued service. | 1/4 of the shares subject to the option vested on May 4, 2024, and 1/48 of the shares subject to the option vest in equal monthly installments thereafter, subject to the Reporting Person's continued service. | 1/4 of the shares subject to the option vested on November 14, 2023, and 1/48 of the shares subject to the option vest in equal monthly installments thereafter, subject to the Reporting Person's continued service.