WASHINGTON, July 11 (Reuters) - Mortgage lender IndyMac Bancorp Inc IMB.N was taken over by the Federal Deposit Insurance Corp on Friday, the second largest financial institution to close in U.S. history.

The FDIC said the estimated cost of the California-based bank’s failure to its insurance fund is between $4 billion and $8 billion. The regulator said it will operate IndyMac to maximize the value of the firm for future sale.

IndyMac’s primary regulator, the Office of Thrift Supervision, blamed a senior lawmaker’s comments for causing a run on the deposits at the largest independent publicly traded U.S. mortgage lender. (Reporting by John Poirier, Karey Wutkowski, Rachelle Younglai; editing by Carol Bishopric)