Fifth Third Bancorp Chief Executive Kevin Kabat says the bank needed a cash infusion of $2 billion to bail out the struggling regional bank.
Regional banks have a large share of assets tied to the sinking housing and mortgage markets.
Fitch Ratings estimates that the mortgage crisis has cost banks $400 billion in losses so far, and the International Monetary Fund said in a report that the amount may rise to nearly $1 trillion before the credit crisis is over.
Analysts at JPMorgan Chase & Co., Merrill Lynch & Co. and UBS AG all said this week that banks may have to cut dividends further and raise more capital to cover losses.