Regeneron director Guarini sells 400 shares at $900

The exercise and sale were reported under a plan intended to comply with Rule 10b5-1(c), adopted February 13, 2026.

Available on EDGAR 11/03/2026 - 04:23 PM EST Accepted by SEC EDGAR 11/03/2026 - 04:22 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

Regeneron Pharmaceuticals, Inc. (REGN) director Kathryn Guarini exercised 400 non-qualified stock options at an exercise price of $719.37 per share on October 30, 2026, acquiring 400 common shares and selling those 400 shares at $900 per share the same day. The transactions were under a plan intended to comply with Rule 10b5-1(c), adopted February 13, 2026. She held 758 options following the exercise; those options expire January 2, 2035.

Insider Trade Summary 10b5-1

Exercise and Sale: 400 shares ($72K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Guarini Kathryn

Role Director

Sold 400 shs ($360K)

Approx. gross sale proceeds $360K

Approx. exercise cost $288K

Approx. pre-tax spread $72K

Type	Security	Shares	Price	Value
Exercise	Non-Qualified Stock Option (right to buy) F1, F2	400	$0.00	$0.00
Exercise	Common Stock F1	400	$719.37	$288K
Sale	Common Stock F1	400	$900.00	$360K

Holdings After Transaction: Non-Qualified Stock Option (right to buy) — 758 contracts (Direct); Common Stock — 603 shares (Direct)

Footnotes (2)

1. F1. Disposition/acquisition made pursuant to a plan intended to comply with Rule 10b5-1(c) adopted on February 13, 2026.
2. F2. On the date of the Company's first annual meeting of shareholders following the date of grant, a portion of these stock options equal to the portion of one year that had passed from the date of grant became exercisable, and the remainder became exercisable on the first anniversary of the date of grant.

Key Figures

Options exercised: 400 options Exercise price: $719.37 per share Common shares acquired: 400 shares +3 more

6 metrics

Options exercised 400 options October 30, 2026

Exercise price $719.37 per share Options exercised October 30, 2026

Common shares acquired 400 shares October 30, 2026

Common shares sold 400 shares October 30, 2026

Sale price $900 per share Common shares sold October 30, 2026

Options following exercise 758 options Following the October 30, 2026 transaction

Key Terms

Non-Qualified Stock Option (right to buy), Rule 10b5-1(c), became exercisable, first anniversary

4 terms

Non-Qualified Stock Option (right to buy) financial

"Non-Qualified Stock Option (right to buy)"

Rule 10b5-1(c) regulatory

"plan intended to comply with Rule 10b5-1(c)"

Rule 10b5-1(c) is an SEC guideline that lets company insiders set up a written, pre-planned schedule to buy or sell their company stock when they are not in possession of material, nonpublic information. For investors, it matters because such plans can reduce the appearance of insider trading by separating decisions from inside knowledge—like putting your trades on autopilot—while also requiring scrutiny since pre-planned trades can still affect market confidence and share value.

became exercisable financial

"a portion of these stock options ... became exercisable"

first anniversary financial

"on the first anniversary of the date of grant"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many REGN shares did Kathryn Guarini sell, and at what price?

Kathryn Guarini sold 400 common shares at $900 per share on October 30, 2026. The sale was under a plan intended to comply with Rule 10b5-1(c), adopted February 13, 2026.

How many REGN stock options did Kathryn Guarini exercise?

Kathryn Guarini exercised 400 non-qualified stock options at an exercise price of $719.37 per share, acquiring 400 common shares on October 30, 2026. She held 758 options following the exercise; those options expire January 2, 2035.

When did Kathryn Guarini's REGN options become exercisable?

A portion equal to the part of one year elapsed since the grant date became exercisable on the date of the Company's first annual meeting after the grant; the remainder became exercisable on the first anniversary of the grant date.

AI-generated analysis. How Rhea-AI works. Not financial advice.

Form 4 Insider Transactions: What Each Field Means →

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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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

X

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^*

Guarini Kathryn

(Last) (First) (Middle)

777 OLD SAW MILL RIVER ROAD

(Street)

TARRYTOWN NEW YORK 10591

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
10/30/2026

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

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

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

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	10/30/2026		M(1)		400	A	$719.37	1,003	D
Common Stock	10/30/2026		S(1)		400	D	$900	603	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)	$719.37	10/30/2026		M(1)			400	(2)	01/02/2035	Common Stock	400	$0.0	758	D

Explanation of Responses:

1. Disposition/acquisition made pursuant to a plan intended to comply with Rule 10b5-1(c) adopted on February 13, 2026.

2. On the date of the Company's first annual meeting of shareholders following the date of grant, a portion of these stock options equal to the portion of one year that had passed from the date of grant became exercisable, and the remainder became exercisable on the first anniversary of the date of grant.

	/s/ Kathryn Guarini	11/03/2026
	** 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.
* Form 4: SEC 1474 (03-26)