X0508 4 2024-05-30 0000744218 Celldex Therapeutics, Inc. CLDX 0001709113 Cavanaugh Sarah C/O CELLDEX THERAPEUTICS, INC. 53 FRONTAGE ROAD, SUITE 220 HAMPTON NJ 08827 false true false false SVP OF CORP AFFAIRS & ADMIN. 0 Common Stock 2024-05-30 4 M 0 10750 2.78 A 12610 D Common Stock 2024-05-30 4 M 0 10103 9.0165 A 22713 D Common Stock 2024-05-30 4 S 0 20853 33.7282 D 1860 D Incentive Stock Option (Right to Buy) 2.78 2024-05-30 4 M 0 10750 0 D 2029-06-19 Common Stock 10750 0 D Incentive Stock Option (Right to Buy) 9.0165 2024-05-30 4 M 0 10103 0 D 2028-06-13 Common Stock 10103 0 D Includes 576 shares of common stock acquired under the Celldex Therapeutics, Inc. 2004 Employee Stock Purchase Plan. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $33.465 to $34.06 per share, inclusive. The reporting person undertakes to provide to Celldex Therapeutics, Inc., any security holder of Celldex Therapeutics, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth herein. As of June 19, 2023, the option is fully vested. As of June 13, 2022, the option is fully vested. /s/ Sam Martin, attorney-in-fact for Sarah Cavanaugh 2024-06-03