X0609 4 2026-04-28 0002058758 Avidia Bancorp, Inc. AVBC 0002076473 Doane Thomas false 42 MAIN ST HUDSON MA 01749 1 EVP- Human Resources 0 Common Stock 2026-04-28 4 P 0 2040 21.16 A 17495 I By 401(k) Common Stock 141 D Common Stock 1096 I By ESOP Reflects transactions not required to be reported pursuant to Section 16 of the Securities Act of 1934, as amended. /s/ Victor L. Cangelosi, pursuant to power of attorney 2026-04-29