In a prospectus for a debt swap offer due to start on Monday, the Tuscan bank said it had set aside 627 million euros to cover for such claims.
The bank, which is seeking to raise 5 billion euros through the debt swap and a share sale, said the potential negative impact of an inspection of its loan portfolio currently being conducted by the European Central Bank was not included in its recently presented business plan.
The bank said the ECB could ask it to book further writedowns on bad loans as a result of the audit with a significant impact on the bank's capital and its financial situation.
The regulator has also told the bank to present a detailed funding plan for each year to 2018 after finding that its liquidity position had weakened, the document said.