Form 4: ACELYRIN Chief Legal Officer Reports Share and Option Conversion Following Alumis Merger Completion

ACELYRIN's Chief Legal Officer, Amar Murugan, has reported the conversion of his common stock, restricted stock units, and stock options into Alumis, Inc. securities following the merger of ACELYRIN into Alumis.

Summary

• On May 21, 2025, ACELYRIN, Inc. completed its merger with Arrow Merger Sub, Inc., a wholly owned subsidiary of Alumis, Inc. (Parent), with ACELYRIN surviving as a wholly owned subsidiary of Parent.
• At the effective time of the merger, each share of ACELYRIN common stock was converted into the right to receive 0.4814 shares of Alumis, Inc. voting common stock, with cash in lieu of fractional shares.
• Amar Murugan, Chief Legal Officer of ACELYRIN, disposed of 121,587 shares of ACELYRIN Common Stock as a result of this conversion, holding 0 shares directly thereafter.
• Outstanding and unvested restricted stock units (RSUs) were assumed by Parent and converted into RSU awards for Parent Common Stock based on the 0.4814 exchange ratio.
• Outstanding and vested RSUs were cancelled and converted into the right to receive Parent Common Stock based on the 0.4814 exchange ratio.
• Outstanding and unexercised stock options with an exercise price of $18.00 or less were assumed by Parent and converted into options to purchase Parent Common Stock, with the number of shares adjusted by the exchange ratio and the exercise price divided by the exchange ratio.
• Mr. Murugan disposed of 525,000 Employee Stock Options with an exercise price of $4.73, holding 0 derivative securities directly thereafter.
• The converted stock options have a vesting schedule where 1/4 of the shares vest on November 13, 2025, and 1/48 of the shares vest in equal monthly installments thereafter, subject to continued service.

Sentiment

Score: 5

Explanation: The sentiment is neutral as this is a procedural filing detailing the conversion of securities as a result of a merger, which was a pre-announced corporate action. It does not convey positive or negative operational or financial performance.

Positives

• The completion of the merger provides clarity and a defined path forward for ACELYRIN shareholders, converting their holdings into shares of Alumis, Inc.
• The continued vesting schedule for the converted stock options provides ongoing incentive and alignment for the Chief Legal Officer with the new parent company, Alumis, Inc.

Negatives

• The filing does not present any inherently negative financial outcomes for the reporting person, as it details a conversion of securities as part of a pre-announced merger rather than a sale at a loss.

Future Outlook

The document indicates that the converted stock options will continue to vest according to a schedule, with the first vesting occurring on November 13, 2025, and subsequent monthly installments, subject to the reporting person's continued service.

Industry Context

This filing reflects the finalization of a significant corporate acquisition within the biotechnology or pharmaceutical sector, where ACELYRIN, Inc. has been acquired by Alumis, Inc. Such mergers are common strategies for companies to consolidate assets, expand pipelines, or achieve economies of scale, and this Form 4 details the procedural impact on insider equity holdings post-merger.

Stakeholder Impact

• Shareholders of ACELYRIN, Inc. have had their shares converted into Alumis, Inc. common stock, impacting their ownership structure and future investment prospects.
• Employees, particularly those with equity compensation like Amar Murugan, have had their ACELYRIN equity converted into Alumis, Inc. equity, aligning their incentives with the new parent company.

Next Steps

• Continued vesting of the converted employee stock options for Amar Murugan, with the next vesting event on November 13, 2025.

Key Dates

Keywords

ACELYRIN, SLRN, Alumis, Merger, Form 4, Insider Trading, Stock Conversion, Restricted Stock Units, Stock Options, Chief Legal Officer, Beneficial Ownership, SEC Filing