Bradesco will take over the 1.2 million card holders currently with American Express (Amex) in Brazil, as the country's biggest non-state bank by assets seeks to benefit from growing demand for consumer credit.
If the deal goes through in July, Bradesco's share of the South American credit card industry will surge by 14 per cent, to around 9.9 million cards.
"The partnership represents an important strategic step for Bradesco, allowing it to expand its client base in a fiercely competitive segment," the company said in a statement.
But Amex claims it is not seeking to leave Brazil, but is simply altering its business model.
Ed Gilligan, head of international operations for Amex told Bloomberg: "American express isn't leaving Brazil we are just changing our business model to a more flexible one, where we think we can grow faster.
"We have some gaps in our business model, we don't have branches and we don't have as many merchants as we would like."
The move will bring Bradesco closer to current market leader Banco Itau, which has more than 11 million customers in Brazil.