After they close Friday, Fairfield's two branches of HSBC Bank will reopen Monday as branches of First Niagara Bank.

The branches -- at 2500 Black Rock Turnpike and at 1761 Post Road -- are among 195 HSBC branches being acquired by Buffalo-based First Niagara in a $1 billion deal.

HSBC ATM and debit cards will not work after 3 p.m. Friday, First Niagara said. Customers already should have received new First Niagara cards and instructions for activating them, the bank said.

Online banking will not be available over the weekend, but HSBC customers have been enrolled in First Niagara's system and will be able to access accounts beginning Monday morning, the bank said. Customers logging in for the first time may use their existing HSBC customer IDs in all caps. They will be prompted to change to a new ID.

Branch hours will not change, and nearly all account and loan numbers will remain the same. Customers whose account numbers needed to change already would have been notified, the bank said.

First Niagara has set up a Web page to guide HSBC customers through the transition -- www.welcometofirstniagara.com. Customers also may call 800-421-0004 for information.