X0609 4 2026-03-25 0001370450 Willdan Group, Inc. WLDN 0001270606 BIEBER MICHAEL A false 2401 EAST KATELLA AVENUE SUITE 300 ANAHEIM CA 92806 true true false false PRESIDENT AND CEO 0 Common Stock 2026-03-25 4 A 0 15750 0 A 255969 D Common Stock 2026-03-25 4 F 0 6444 82.80 D 249525 D Represents performance-based restricted stock units previously granted to the Reporting Person by the Issuer on March 20, 2024. The performance conditions applicable to the award were determined to have been satisfied by the Issuer's Compensation Committee effective on March 25, 2026, resulting in the immediate vesting of the restricted stock units as to 15,750 shares of Common Stock. Includes (i) 18,000 shares of restricted stock units that vest in three substantially equal installments on each of March 3, 2027, March 3, 2028 and March 3, 2029, (ii) 12,834 shares of restricted stock units that vest in two substantially equal installments on each of March 17, 2027 and March 17, 2028, and (iii) 5,834 shares of restricted stock units that vest on March 20, 2027, subject to the Reporting Person's continued service to the Issuer through the applicable vesting date. Represents shares of the Issuer's Common Stock withheld to satisfy tax withholding obligations in connection with the vesting of the performance-based restricted stock units referenced in footnote (1). /s/ Creighton K. Early, Attorney-in-fact for Michael A. Bieber 2026-03-26