X0508 4 2026-01-07 0 0000872589 REGENERON PHARMACEUTICALS, INC. REGN 0001683607 Bassler Bonnie L 777 OLD SAW MILL RIVER ROAD TARRYTOWN NY 10591 1 0 0 0 1 Common Stock 2026-01-07 4 M 0 1500 374.12 A 3203 D Common Stock 2026-01-07 4 S 0 1500 800.0 D 1703 D Non-Qualified Stock Option (right to buy) 374.12 2026-01-07 4 M 0 1500 0.0 D 2030-01-02 Common Stock 1500 2861 D Disposition/acquisition made pursuant to a plan intended to comply with Rule 10b5-1(c) adopted on May 2, 2025. Represents volume-weighted average price of sales of 1,500 shares of Company stock on January 7, 2026 at prices ranging from $800.00 to $800.01. 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 January 7, 2026 at each separate price. 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/ Bonnie L. Bassler 2026-01-08