Federal regulators said Tuesday that the failure last month of IndyMac Bancorp Inc. has cost the government more than originally anticipated.

During the Federal Deposit Insurance Corp.’s quarterly bank briefing, Chairman Sheila Bair said closing IndyMac has cost its insurance fund $8.9 billion. When the FDIC closed the Pasadena-based mortgage lender July 11, regulators said they expected the tab to run between $4 billion and $8 billion.

Some of the higher costs stem from the agency’s effort to make the thrift more attractive by relaxing the terms of mortgages for IndyMac borrowers behind on their payments.

The FDIC has so far unsuccessfully tried to find a buyer for IndyMac’s assets. But Bair said the FDIC plans to ramp up its efforts to sell the bank, either as a whole or in pieces, in the next quarter.

The FDIC also said in its briefing that the number of troubled banks in the U.S. has risen 30 percent to 117, the highest level in five years. The banking sector’s quarterly earnings, meanwhile, dropped 86 percent to $5 billion.