A legal challenge by Quicken Loans Inc. to the U.S. government's aggressive scrutiny of its Federal Housing Administration mortgage loans reflects widespread industry unease with government investigation of lenders, financial-services lawyers said.

“All of the lenders that we've worked with have basically felt the same way as Quicken Loans in terms of the process and the changing of the rules of the game,” said Jeff Naimon, a partner at BuckleySandler in Washington. He defends banks and other financial-services companies but isn't involved in the Quicken Loans case.

The FHA approves lenders to issue loans backed by its mortgage insurance, which protects the banks against homeowner default.