Addressing a conference on banking today, Federal Reserve Chairman Ben Bernanke restated the Fed's concerns that mortgage lending standards remain too tight. While a return to "pre-crisis lending standards" for home loans "wouldn't be appropriate," Bernanke said current standards "may be limiting or preventing lending to many creditworthy borrowers." A recent Fed survey showed banks are less willing to originate loans that meet Fannie Mae and Freddie Mac's minimum credit scores than they were in 2006 — in some cases, even when borrowers make 20 percent down payments. The reason, Bernanke said, is the risk that Fannie and Freddie will make them buy back defaulted loans if the underwriting or documentation is judged deficient. In a Jan. 4 white paper, the Federal Reserve outlined what it sees as "extraordinary problems plaguing the housing market," including an excess supply of vacant homes, tight mortgage credit, and the costs of an "unwieldy and inefficient" foreclosure process.