Sec Form 4 Filing - YANCOPOULOS GEORGE @ REGENERON PHARMACEUTICALS, INC. - 2024-05-15

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

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person YANCOPOULOS GEORGE 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 X __ Officer (give title below) _____ Other (specify below) Bd. Co-Chair, President & CSO (Last) (First) (Middle) 777 OLD SAW MILL RIVER ROAD 3. Date of Earliest Transaction (MM/DD/YY) 05/15/2024 (Street) TARRYTOWN, NY10591 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 05/15/2024 S( 1 ) 111 D $ 965.69 ( 2 ) 886,272 D Common Stock 05/15/2024 S( 1 ) 782 D $ 966.29 ( 3 ) 885,490 D Common Stock 05/15/2024 S( 1 ) 1,428 D $ 967.45 ( 4 ) 884,062 D Common Stock 05/15/2024 S( 1 ) 3,387 D $ 968.43 ( 5 ) 880,675 D Common Stock 05/15/2024 S( 1 ) 1,930 D $ 969.14 ( 6 ) 878,745 D Common Stock 05/15/2024 S( 1 ) 846 D $ 970.36 ( 7 ) 877,899 D Common Stock 05/15/2024 S( 1 ) 406 D $ 971.28 ( 8 ) 877,493 D Common Stock 05/15/2024 S( 1 ) 784 D $ 972.5 ( 9 ) 876,709 D Common Stock 05/15/2024 S( 1 ) 1,865 D $ 973.43 ( 10 ) 874,844 D Common Stock 05/15/2024 S( 1 ) 4,778 D $ 974.47 ( 11 ) 870,066 D Common Stock 05/15/2024 S( 1 ) 5,225 D $ 975.6 ( 12 ) 864,841 D Common Stock 05/15/2024 S( 1 ) 6,885 D $ 976.56 ( 13 ) 857,956 D Common Stock 05/15/2024 S( 1 ) 9,851 D $ 977.42 ( 14 ) 848,105 D Common Stock 05/15/2024 S( 1 ) 4,865 D $ 978.44 ( 15 ) 843,240 D Common Stock 05/15/2024 S( 1 ) 504 D $ 979.87 ( 16 ) 842,736 D Common Stock 05/15/2024 S( 1 ) 1,223 D $ 980.72 ( 17 ) 841,513 D Common Stock 05/15/2024 S( 1 ) 2,283 D $ 981.52 ( 18 ) 839,230 D Common Stock 05/15/2024 S( 1 ) 303 D $ 982.29 ( 19 ) 838,927 D Common Stock 05/15/2024 S( 1 ) 727 D $ 983.88 ( 20 ) 838,200 D Common Stock 05/15/2024 S( 1 ) 53 D $ 984.02 838,147 D Common Stock 05/15/2024 S( 1 ) 647 D $ 985.62 ( 21 ) 837,500 D Common Stock 05/15/2024 S( 1 ) 442 D $ 986.4 ( 22 ) 837,058 D Common Stock 05/15/2024 S( 1 ) 182 D $ 987.38 ( 23 ) 836,876 D Common Stock 05/15/2024 S( 1 ) 373 D $ 988.36 ( 24 ) 836,503 D Common Stock 05/15/2024 S( 1 ) 120 D $ 989.14 ( 25 ) 836,383 D Common Stock 5,903 I By 401(k) Plan Common Stock 180,000 I By Trust for Chldn. ( 26 ) Common Stock 158,410 I by 2022 GRAT II Common Stock 18,148 I by Children

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other YANCOPOULOS GEORGE 777 OLD SAW MILL RIVER ROAD TARRYTOWN, NY10591 X Bd. Co-Chair, President & CSO Signatures /s/**George D. Yancopoulos 05/17/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Disposition/acquisition made pursuant to plans intended to comply with Rule 10b5-1(c) adopted on February 14, 2024. ( 2 )Represents volume-weighted average price of sales of 111 shares of Company stock on May 15, 2024 at prices ranging from $965.58 to $965.70. 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 May 15, 2024 at each separate price. ( 3 )Represents volume-weighted average price of sales of 782 shares of Company stock on May 15, 2024 at prices ranging from $966.04 to $966.68. 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 May 15, 2024 at each separate price. ( 4 )Represents volume-weighted average price of sales of 1,428 shares of Company stock on May 15, 2024 at prices ranging from $967.07 to $967.99. 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 May 15, 2024 at each separate price. ( 5 )Represents volume-weighted average price of sales of 3,387 shares of Company stock on May 15, 2024 at prices ranging from $968.06 to $968.90. 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 May 15, 2024 at each separate price. ( 6 )Represents volume-weighted average price of sales of 1,930 shares of Company stock on May 15, 2024 at prices ranging from $969.03 to $969.96. 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 May 15, 2024 at each separate price. ( 7 )Represents volume-weighted average price of sales of 846 shares of Company stock on May 15, 2024 at prices ranging from $970.26 to $970.95. 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 May 15, 2024 at each separate price. ( 8 )Represents volume-weighted average price of sales of 406 shares of Company stock on May 15, 2024 at prices ranging from $971.02 to $971.37. 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 May 15, 2024 at each separate price. ( 9 )Represents volume-weighted ave rage price of sales of 784 shares of Company stock on May 15, 2024 at prices ranging from $972.05 to $972.92. 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 May 15, 2024 at each separate price. ( 10 )Represents volume-weighted average price of sales of 1,865 shares of Company stock on May 15, 2024 at prices ranging from $973.00 to $973.99. 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 May 15, 2024 at each separate price. ( 11 )Represents volume-weighted average price of sales of 4,778 shares of Company stock on May 15, 2024 at prices ranging from $974.01 to $974.98. 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 May 15, 2024 at each separate price. ( 12 )Represents volume-weighted average price of sales of 5,225 shares of Company stock on May 15, 2024 at prices ranging from $975.05 to $975.99. 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 May 15, 2024 at each separate price. ( 13 )Represents volume-weighted average price of sales of 6,885 shares of Company stock on May 15, 2024 at prices ranging from $976.00 to $976.99. 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 May 15, 2024 at each separate price. ( 14 )Represents volume-weighted average price of sales of 9,851 shares of Company stock on May 15, 2024 at prices ranging from $977.00 to $977.99. 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 May 15, 2024 at each separate price. ( 15 )Represents volume-weighted average price of sales of 4,865 shares of Company stock on May 15, 2024 at prices ranging from $978.01 to $978.97. 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 May 15, 2024 at each separate price. ( 16 )Represents volume-weighted average price of sales of 504 shares of Company stock on May 15, 2024 at prices ranging from $979.18 to $979.95. 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 May 15, 2024 at each separate price. ( 17 )Represents volume-weighted average price of sales of 1,223 shares of Company stock on May 15, 2024 at prices ranging from $980.11 to $980.99. 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 May 15, 2024 at each separate price. ( 18 )Represents volume-weighted average price of sales of 2,283 shares of Company stock on May 15, 2024 at prices ranging from $981.06 to $981.95. 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 May 15, 2024 at each separate price. ( 19 )Represents volume-weighted average price of sales of 303 shares of Company stock on May 15, 2024 at prices ranging from $982.00 to $982.73. 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 May 15, 2024 at each separate price. ( 20 )Represents volume-weighted average price of sales of 727 shares of Company stock on May 15, 2024 at prices ranging from $983.21 to $983.99. 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 May 15, 2024 at each separate price. ( 21 )Represents volume-weighted average price of sales of 647 shares of Company stock on May 15, 2024 at prices ranging from $985.11 to $985.94. 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 May 15, 2024 at each separate price. ( 22 )Represents volume-weighted average price of sales of 442 shares of Company stock on May 15, 2024 at prices ranging from $986.30 to $986.96. 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 May 15, 2024 at each separate price. ( 23 )Represents volume-weighted average price of sales of 182 shares of Company stock on May 15, 2024 at prices ranging from $987.03 to $987.63. 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 May 15, 2024 at each separate price. ( 24 )Represents volume-weighted average price of sales of 373 shares of Company stock on May 15, 2024 at prices ranging from $988.00 to $988.99. 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 May 15, 2024 at each separate price. ( 25 )Represents volume-weighted average price of sales of 120 shares of Company stock on May 15, 2024 at prices ranging from $989.01 to $989.28. 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 May 15, 2024 at each separate price. ( 26 )As investment trustee of trusts for the benefit of the reporting person's children.

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).

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