Credit-Card Firms Face More Exposure to Losses Under Brazil Plan

Visa Inc., Mastercard Inc. and other card networks doing business in Brazil will soon be required to shoulder more of the risk if something goes wrong with transactions conducted on their systems.

The networks have until May to comply with new rules published by the central bank in November, which regulators said make clear that the card network is “fully responsible, without exceptions, for ensuring payment of all transactions to the receiving user, including using its own funds if the protection mechanisms adopted prove insufficient.”

The issue took on new relevance with the failure of Banco Master SA and ...