Regeneron Pharmaceuticals Director Files Form 144 to Sell $1.58M in Common Stock

Executive Summary

On October 30, 2026, Michael S. Brown, a Director of Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN), filed a Form 144 notice of proposed sale of securities with the SEC. The filing covers the planned disposition of 1,929 shares of common stock with an aggregate market value of approximately $1,579,407.33 (implied price of ~$818.77 per share).

Transaction & Acquisition Details

• Security: Common Stock
• Proposed Sale Date: October 30, 2026
• Units to be Sold: 1,929 shares
• Aggregate Market Value: $1,579,407.33
• Shares Outstanding: 103,447,859 shares
• Dilution / Float Impact: Minimal (~0.0019% of total shares outstanding)
• Acquisition Nature: Exercise of Stock Options directly from the issuer on October 30, 2026, paid in cash
• Executing Broker: Morgan Stanley Smith Barney LLC Executive Financial Services

Governance & Trading Plan Insights

The transaction is executed pursuant to a pre-arranged Rule 10b5-1 trading plan adopted on February 25, 2026, well in advance of the sale. This cooling-off period and pre-scheduled plan structure indicates the sale is routine and not an opportunistic transaction driven by non-public information. Additionally, the filer reported no other securities sold during the past three months.

Market & Trading Significance

The trading significance is assessed as Low. The volume represents a very small fraction of Regeneron's total share float and regular trading liquidity, and the sale is conducted pursuant to an option exercise under an established Rule 10b5-1 trading plan.