Form 4: Alnylam Exec's Stock Transactions Post-PSU Vesting

Alnylam Pharmaceuticals' CSO and EVP, Kevin Fitzgerald, acquired 4,953 shares through performance-based stock unit vesting and subsequently sold 2,238 shares to cover tax obligations.

Summary

• Kevin Joseph Fitzgerald, CSO & EVP, Head of Research at Alnylam Pharmaceuticals, Inc. (ALNY), reported changes in beneficial ownership.
• On October 1, 2025, Fitzgerald acquired 2,102 shares of common stock due to the vesting of a performance-based stock unit (PSU) granted on February 24, 2021. This vesting was triggered by the public reporting of the initiation of a Phase 3 clinical study for an RNAi therapeutic in a prevalent disease.
• Also on October 1, 2025, Fitzgerald acquired an additional 2,851 shares of common stock from the vesting of another PSU granted on March 1, 2024. This vesting was based on the public reporting of the initiation of a Phase 3 clinical study in a prevalent indication.
• On October 2, 2025, a total of 2,238 shares of common stock were automatically sold by the company on Fitzgerald's behalf. These sales were mandatory "sell-to-cover" transactions to meet minimum statutory tax withholding obligations arising from the PSU vestings.
• The sales occurred at weighted average prices ranging from $446.53 to $457.64 per share.
• Following these transactions, Fitzgerald directly beneficially owns 25,231 shares of common stock and indirectly owns 537 shares through a managed 401(k) account.

Sentiment

Score: 6

Explanation: The vesting of performance-based stock units indicates the achievement of significant clinical development milestones (initiation of Phase 3 studies), which is a positive operational indicator. The subsequent sales are routine 'sell-to-cover' transactions for tax obligations and do not reflect a negative sentiment from the insider.

Positives

• Vesting of 4,953 performance-based stock units indicates the achievement of significant corporate milestones, specifically the initiation of two Phase 3 clinical studies for RNAi therapeutics.
• The successful initiation of Phase 3 trials suggests progress in Alnylam's drug development pipeline.

Negatives

• A total of 2,238 shares were sold, reducing the direct beneficial ownership of the executive.
• The sales, while for tax purposes, represent a reduction in the executive's direct equity stake in the company.

Future Outlook

The vesting of performance-based stock units was triggered by the public reporting of the initiation of Phase 3 clinical studies for RNAi therapeutics in prevalent diseases/indications, signaling continued progress in the company's clinical development pipeline.

Industry Context

The initiation of Phase 3 clinical studies is a critical milestone in the biotechnology and pharmaceutical industry, indicating a drug candidate's progression towards potential market approval. For Alnylam, a leader in RNAi therapeutics, advancing multiple candidates into late-stage trials reinforces its pipeline strength and commitment to addressing prevalent diseases.

Stakeholder Impact

• Shareholders: Provides transparency into executive compensation and confirms the achievement of clinical development milestones, which could be viewed positively for the company's pipeline.
• Employees: Reflects the company's progress in clinical trials, potentially boosting morale and confidence in the company's strategic direction.

Next Steps

• Continued progression of the two RNAi therapeutic candidates through Phase 3 clinical studies.
• Ongoing evaluation by the People, Culture and Compensation (PC&C) Committee of the Issuer Board of Directors for future performance-based awards.

Key Dates

Recommendation

This Form 4 primarily details routine executive compensation events, specifically the vesting of performance-based stock units and subsequent sell-to-cover transactions for tax obligations. While the vesting indicates the achievement of clinical milestones (Phase 3 initiation), the sales are administrative and do not reflect a change in investment sentiment by the insider. Therefore, it provides no new fundamental information to alter an existing investment thesis, warranting a 'hold' recommendation based solely on this filing.

Keywords

Alnylam Pharmaceuticals, ALNY, Form 4, Insider Trading, Executive Compensation, Performance Stock Units, PSU Vesting, Sell-to-Cover, Phase 3 Clinical Trials, RNAi Therapeutics, Biotechnology, Pharmaceuticals