As of January next year, BB will have access to the Brazilian postal service's 6,195 points of service covering 95% of all municipalities in the country. The contract gives BB the exclusive right to provide banking services to the postal service's customers over five years.
"Through this investment, Banco do Brasil anticipates the implementation of a strategic plan that aims to extend its service points for all Brazilian municipalities," BB said in a statement announcing the deal.
Bradesco recently outbid BB - and two private sector banks - in the auction of Rio de Janeiro state bank Berj.
BB is the largest lender in Brazil, and Bradesco ranks as second biggest among the country's private banks.