Leonard S. Schleifer - 31 Dec 2025 Form 4 Insider Report for REGENERON PHARMACEUTICALS, INC. (REGN)

Role: Bd. Co-Chair, President & CEO, Director
Signature: /s/ Leonard S. Schleifer
Issuer symbol: REGN
Transactions as of: 31 Dec 2025
Net transactions value: -$22,058,611
Form type: 4
Filing time: 05 Jan 2026, 17:53:17 UTC
Previous filing: 11 Dec 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
SCHLEIFER LEONARD S	Bd. Co-Chair, President & CEO, Director	777 OLD SAW MILL RIVER ROAD, TARRYTOWN	/s/ Leonard S. Schleifer	05 Jan 2026	0001218629

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership
transaction	REGN	Common Stock	Options Exercise	$0	+28,570	+13%	$0.000000	243,093	31 Dec 2025	Direct
transaction	REGN	Common Stock	Tax liability	$22,058,611	-28,570	-12%	$772.09	214,523	31 Dec 2025	Direct
holding	REGN	Common Stock						127,484	31 Dec 2025	By 2024 GRAT
holding	REGN	Common Stock						300,000	31 Dec 2025	By 2025 GRAT
holding	REGN	Common Stock						5,989	31 Dec 2025	By 401(k) Plan
holding	REGN	Common Stock						39,985	31 Dec 2025	By Trust

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	REGN	2020 Performance Stock Units	Options Exercise	$0	-28,570	-4.6%	$0.000000	595,077	31 Dec 2025	Common Stock	28,570		Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Each performance restricted stock unit ("PSU") represents a contingent right to receive one share of Company stock. These PSUs were earned during the applicable five-year performance period and vested on December 31, 2025 but remain subject to a mandatory holding period of three years after vesting, which ends early upon the reporting person's death or disability or a change in control of the Company.

Content

Each performance restricted stock unit ("PSU") represents a contingent right to receive one share of Company stock. These PSUs were earned during the applicable five-year performance period and vested on December 31, 2025 but remain subject to a mandatory holding period of three years after vesting, which ends early upon the reporting person's death or disability or a change in control of the Company.