Form 4: ALUMIS Director Boosts Stake with $533K Share Purchase

James B. Tananbaum, a Director and 10% owner of ALUMIS INC., acquired 72,212 shares of common stock for $7.38 per share, totaling approximately $533,000.

Summary

• James B. Tananbaum, a Director and 10% owner of ALUMIS INC. (ALMS), purchased 72,212 shares of common stock.
• The transaction occurred on November 21, 2025, at a price of $7.38 per share.
• The total value of the acquisition was approximately $533,000.
• The shares were acquired indirectly through various Foresite Capital and Foresite Labs funds and LLCs, where Tananbaum serves as a managing member or manager.
• Following this transaction, Tananbaum's indirect beneficial ownership across these entities totals 15,778,040 shares.
• The transaction was made pursuant to a Rule 10b5-1(c) pre-arranged trading plan.

Sentiment

Score: 7

Explanation: The acquisition of shares by a director and 10% owner, even if pre-planned, generally indicates confidence in the company's valuation and future prospects, which is a positive signal for investors.

Positives

• A Director and 10% owner, James B. Tananbaum, increased beneficial ownership in ALUMIS INC. by acquiring 72,212 shares.
• Insider buying, especially from a significant shareholder and director, often signals confidence in the company's future prospects.
• The purchase was made at $7.38 per share, representing a direct investment by the insider.

Negatives

• No specific negative information is contained within this Form 4 filing.

Risks

• This Form 4 filing does not detail specific risks related to ALUMIS INC.'s operations or financial health. It is a disclosure of an insider transaction.

Future Outlook

This Form 4 filing is a disclosure of an insider transaction and does not contain forward-looking statements or guidance regarding ALUMIS INC.'s future outlook.

Industry Context

This insider transaction by a director and significant owner of ALUMIS INC. reflects individual confidence in the company. It does not inherently provide broader industry trends or competitive analysis, though sustained insider buying across an industry could signal sector-wide optimism.

Related Party Transactions

• The shares are held indirectly through various investment funds and LLCs (Foresite Capital Opportunity Fund V, L.P., Foresite Capital Fund VI, L.P., Foresite Capital Fund V, L.P., Labs Co-Invest V, LLC, Foresite Labs Fund I, L.P., and Foresite Labs Affiliates 2021, LLC) where James B. Tananbaum serves as a managing member or manager, establishing a related party relationship for beneficial ownership purposes. Tananbaum disclaims beneficial ownership of these shares except to the extent of his pecuniary interest.

Stakeholder Impact

• Shareholders: May view the insider purchase as a positive signal of management's confidence in the company's future, potentially influencing investor sentiment and stock price.
• Management/Employees: The transaction by a director and significant owner could reinforce internal confidence and alignment of interests.

Next Steps

• This Form 4 filing does not mention any specific future actions, events, or milestones for ALUMIS INC. beyond the reported transaction.

Key Dates

Recommendation

The insider purchase by a director and 10% owner, James B. Tananbaum, signals confidence in ALUMIS INC.'s future. While this is a positive indicator, it's a single transaction, albeit a significant one in terms of value. A 'hold' recommendation is appropriate as it suggests maintaining current positions based on this positive signal, but further analysis of the company's fundamentals, financial performance, and broader market conditions would be required for a 'buy' recommendation.

Keywords

ALUMIS INC., ALMS, James B. Tananbaum, Insider Trading, Form 4, Share Purchase, Director, 10% Owner, Equity Acquisition, Foresite Capital