X0508 4 2025-08-26 0002058758 Avidia Bancorp, Inc. AVBC 0002077951 Nelson Jonathan Michael 42 MAIN ST HUDSON MA 01749 1 CFO and Treasurer 0 Common Stock 2025-08-26 4 P 0 6631 15.0806 A 16554 I By 401(k) Common Stock 7000 D /s/ Victor L. Cangelosi, pursuant to power of attorney 2025-08-27