SEC Filing Analysis: ALNYLAM PHARMACEUTICALS, INC. (ALNY)

Executive Summary

• Trading Significance: Low
• Key Takeaway: CSO executes routine tax-related sales and a pre-planned 10b5-1 divestment totaling ~$1M.
• Market Impact: Neutral - Transaction size is negligible relative to the company's $44B market cap.

Company Information

Field	Value
Company	ALNYLAM PHARMACEUTICALS, INC.
Ticker Symbol	ALNY
CIK	0001178670
Industry	Pharmaceutical Preparations

Insider Information

Field	Value
Name	Fitzgerald Kevin Joseph
CIK	0001886431
Title/Position	CSO & EVP, Head of Research
Relationship	Officer

Transaction Details

Field	Value
Form Type	4
Transaction Date	2026-03-03
Transaction Code	S (Sale)
Security Type	Common Stock
Shares Involved	3,250 (Total Sold)
Price Per Share	~$323.75 (Weighted Avg)
Total Value	~$1,052,189
Shares Owned After	21,860
Ownership Type	Direct

Financial Impact Assessment

Transaction Materiality

Metric	Value
Transaction Value	$1,052,189
% of Market Cap	0.0024%
Shares Transacted	3,250
% of Shares Outstanding	0.0025%
Post-Transaction Ownership	21,860 shares (0.016% of outstanding)
Materiality Assessment	Low

Impact Evaluation

• Market Cap Context: For a Large Cap company ($44.15B), a $1M transaction is routine and immaterial to liquidity.
• Ownership Concentration: The insider holds a relatively small stake (<0.1%) of the total 132M shares outstanding.
• Dilution Impact: The filing also includes a grant of 8,105 options and 3,688 RSUs. While dilutive, the amount is negligible (0.008% of float).
• Transaction Significance: The sales represent <0.1% of market cap, falling well below the threshold for market significance.

Market Impact Analysis

Stock Impact Prediction

• Direction: Neutral
• Reasoning: The sales are split between mandatory tax withholding (approx. 50%) and a Rule 10b5-1 trading plan (approx. 50%). Neither indicates a shift in sentiment.

Volume & Sentiment

• Expected Volume Impact: None. The 3,250 shares sold are a fraction of daily volume for a stock of this size.
• Sentiment Indicator: Neutral. The 10b5-1 plan was adopted in August 2025, removing immediate timing significance.

Additional Context

Transaction Notes

• Timing: Transactions occurred on March 2 (Tax sales) and March 3 (Planned sales).
• Special Circumstances:
  • Tax Withholding: 1,598 shares were sold automatically to cover taxes on RSU vesting.
  • 10b5-1 Plan: 1,652 shares were sold under a plan adopted 2025-08-14.
  • New Grants: The insider also received 8,105 stock options (strike $325.07) and 3,688 RSUs, indicating continued long-term alignment.