[Form 4] REGENERON PHARMACEUTICALS, INC. Insider Trading Activity

Rhea-AI Filing Summary

Regeneron Pharmaceuticals (REGN) director Christine A. Poon reported insider transactions. On 10/29/2025, she exercised 6,500 non-qualified stock options at $520.01 and sold shares in multiple trades: 650 at $652.68, 2,735 at $653.5, 1,915 at $654.42, 100 at $655.1, 712 at $656.5, and 388 at $657.29.

On 10/30/2025, she exercised an additional 2,712 options at $520.01. Following the reported transactions, she beneficially owned 5,064 shares, held directly.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

POON CHRISTINE A

(Last) (First) (Middle)

777 OLD SAW MILL RIVER ROAD

(Street)

TARRYTOWN NY 10591

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
REGENERON PHARMACEUTICALS, INC. [ REGN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
10/29/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/29/2025		M		6,500	A	$520.01	8,852	D
Common Stock	10/29/2025		S		650	D	$652.68(1)	8,202	D
Common Stock	10/29/2025		S		2,735	D	$653.5(2)	5,467	D
Common Stock	10/29/2025		S		1,915	D	$654.42(3)	3,552	D
Common Stock	10/29/2025		S		100	D	$655.1(4)	3,452	D
Common Stock	10/29/2025		S		712	D	$656.5(5)	2,740	D
Common Stock	10/29/2025		S		388	D	$657.29(6)	2,352	D
Common Stock	10/30/2025		M		2,712	A	$520.01	5,064	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Non-Qualified Stock Option (right to buy)	$520.01	10/29/2025		M			6,500	(7)	01/04/2026	Common Stock	6,500	$0.0	2,712	D
Non-Qualified Stock Option (right to buy)	$520.01	10/30/2025		M			2,712	(7)	01/04/2026	Common Stock	2,712	$0.0	0	D

Explanation of Responses:

1. Represents volume-weighted average price of sales of 650 shares of Company stock on October 29, 2025 at prices ranging from $652.31 to $652.94. Upon request by the Commission staff, the Company, or a security holder of the Company, the reporting person will provide full information regarding the number of shares sold by the reporting person on October 29, 2025 at each separate price.

2. Represents volume-weighted average price of sales of 2,735 shares of Company stock on October 29, 2025 at prices ranging from $653.05 to $653.98. Upon request by the Commission staff, the Company, or a security holder of the Company, the reporting person will provide full information regarding the number of shares sold by the reporting person on October 29, 2025 at each separate price.

3. Represents volume-weighted average price of sales of 1,915 shares of Company stock on October 29, 2025 at prices ranging from $654.01 to $654.93. Upon request by the Commission staff, the Company, or a security holder of the Company, the reporting person will provide full information regarding the number of shares sold by the reporting person on October 29, 2025 at each separate price.

4. Represents volume-weighted average price of sales of 100 shares of Company stock on October 29, 2025 at prices ranging from $655.02 to $655.16. Upon request by the Commission staff, the Company, or a security holder of the Company, the reporting person will provide full information regarding the number of shares sold by the reporting person on October 29, 2025 at each separate price.

5. Represents volume-weighted average price of sales of 712 shares of Company stock on October 29, 2025 at prices ranging from $656.33 to $656.93. Upon request by the Commission staff, the Company, or a security holder of the Company, the reporting person will provide full information regarding the number of shares sold by the reporting person on October 29, 2025 at each separate price.

6. Represents volume-weighted average price of sales of 388 shares of Company stock on October 29, 2025 at prices ranging from $657.02 to $657.78. Upon request by the Commission staff, the Company, or a security holder of the Company, the reporting person will provide full information regarding the number of shares sold by the reporting person on October 29, 2025 at each separate price.

7. The stock option vested in three equal annual installments, commencing one year after the date of grant.

	/s/ Christine A. Poon	10/31/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did REGN insider Christine A. Poon report on Form 4?

She exercised non‑qualified stock options and sold Regeneron common stock in multiple trades on 10/29/2025, and exercised additional options on 10/30/2025.

How many Regeneron options did the director exercise?

6,500 options at $520.01 on 10/29/2025 and 2,712 options at $520.01 on 10/30/2025.

At what prices were REGN shares sold on 10/29/2025?

Volume‑weighted average prices included $652.68, $653.5, $654.42, $655.1, $656.5, and $657.29 across several trades.

How many REGN shares does the insider own after these trades?

Following the reported transactions, the insider beneficially owned 5,064 shares, held directly.

What is the insider’s relationship to Regeneron (REGN)?

The reporting person is a Director of Regeneron Pharmaceuticals, Inc.