Banco do Brasil SA, the largest retail bank in Brazil, wants to use technology from Fiserv Inc. to enter the U.S. retail business, with an emphasis on serving the unbanked and underbanked.

Fiserv said this week that Banco do Brasil, which is controlled by the Brazilian government but has publicly traded stock, has agreed to use the Premier core processing system from the Brookfield, Wis., vendor's Information Technology Inc.

The deal is contingent on regulatory approval of a charter for Banco do Brasil.

Michael C. Homer, a vice president at ITI and its general manager of professional services, said Banco do Brasil would use other products and services from his unit, including credit and debit card processing and lending and risk management technology.

"It's a full suite," Mr. Homer said.

In targeting the underbanked, Banco do Brasil is pursuing a strategy that some U.S. banks have begun to develop in recent years to improve service to Spanish-speaking immigrants and bring them into the banking system.

Leonard Whyte, Banco do Brasil's deputy general manager in New York, said in a Fiserv press release that the issues are different for his bank's prospective customers in this country.

"We found large pockets of Brazilian immigrants throughout the U.S. who are not adequately served by existing banking institutions, mostly because they are primarily Portuguese-speaking," Mr. Whyte said. "This market is an obvious niche for the bank."

A spokeswoman for the bank said that it has applied for a federal savings bank charter and a money transfer license, and that executives would not discuss their plans while the applications are pending.

Fiserv said the $160 billion-asset bank Banco do Brasil plans initially to open five branches. Mr. Homer said he does not know what markets the bank is targeting.

Guillermo Kopp, an executive director and global research fellow at TowerGroup, a Needham, Mass., independent research firm owned by MasterCard Inc., said that U.S. banks have begun to recognize the potential of the Hispanic market, but "there's been less progress in targeting the Portuguese-speaking community."

In Brazil's fast-growing market, "in terms of revenue momentum, Banco do Brasil is trailing its competitors," including Banco Bradesco SA and Banco Itau Holdings Financiera SA, Mr. Kopp said. "Globalization is taking hold. They need to grow regionally or grow internationally. That is what is going on with Banco do Brasil."