BBVA, the Spanish bank, on Wednesday emerged as the frontrunner in the auction for Guaranty Financial, a struggling Texas bank with $14bn in assets that US regulators have been working to sell for the past six weeks.

BBVA was thought to have been offered loss-sharing protection from the Federal Deposit Insurance Corporation as part of the deal, said people who were involved in the process. In some past rescue deals, the FDIC has agreed to absorb 80 per cent of losses up to a certain level and 95 per cent of losses beyond that point.