Exhibit A

JOINT FILING AGREEMENT

The undersigned agree that this Schedule 13G Amendment No. 1 dated February 12, 2025 relating to the Common Stock, par value $0.01 per share, of NB Bancorp, Inc. shall be filed on behalf of the undersigned.

PERTENTO PARTNERS LLP

By: /s/ Eduardo Marques

Name: Eduardo Marques

Title:   Managing Partner

EDUARDO MARQUES

By: /s/ Eduardo Marques