X0609 4 2026-10-13 0002139097 TRex Bio, Inc. TRXB 0001216955 MARCUS JOEL S false C/O TREX BIO, INC. 269 EAST GRAND AVENUE, SUITE 300 SOUTH SAN FRANCISCO CA 94080 true false false false false Common Stock 2026-10-13 4 C false 41871 A 41871 D Series B Convertible Preferred Stock 2026-10-13 4 C false 161828 0 D Common Stock 41871 0 D On October 13, 2026, the shares of Series B Convertible Preferred Stock automatically converted into shares of Common Stock on a 3.8649-to-1 basis without payment of further consideration immediately prior to the closing of the Issuer's initial public offering. The shares have no expiration date. /s/ Brandon Hants, as attorney-in-fact 2026-10-13