The rescue of regional savings bank CajaSur, which was taken over by the Bank of Spain at the weekend, could cost up to 2.7 billion euros, a business newspaper reported Monday.
A Bank of Spain spokesman would not confirm the figure but said the unlisted bank, formerly controlled by the Roman Catholic Church and headed by a priest, would receive an injection of "at least" 523 million euros (657 million dollars).
That would be the "legal minimum" amount to ensure financial stability.
"At least 523 million euros will be needed but I can not indicate a precise figure regarding the injection of capital which will be necessary," he told AFP.
The business daily Expansion said supplementary funds will be needed to clean up the bank's 1.5 billion euros in doubtful debts and another 364 million euros to make up for irrecoverable credits and the depreciation of property assets.