WASHINGTON, May 14 (Reuters) - The U.S. Federal Reserve is considering letting ratings agencies besides the three major firms rate a range of securities eligible for a Fed program aimed at getting credit flowing in the economy, Fed Chairman Ben Bernanke said in a letter made public on Thursday.

"Although ratings provided by only the three major agencies are currently eligible for the TALF, the Federal Reserve is in the process of analyzing the potential for expansion to include other agencies," Bernanke said in a letter to Connecticut Attorney General Richard Blumenthal dated April 13.

The Fed on May 1 said it is reviewing whether to let all ratings agencies that want to rate commercial mortgage-backed securities under the Term Asset-backed Loan Facility, or TALF, participate. The review is still in process, a New York Fed spokesperson said on Thursday.

Bernanke's letter left open the possibility that other classes of TALF securities such as student or credit card loans might be open to be rated by a wider group of ratings agencies. A Fed spokesman declined to comment.

The Fed launched TALF in November to boost small business and consumer loan securitization and has expanded it in size and to include commercial property loans.

Blumenthal, who released the letter, has said that by allowing only the three major ratings agencies -- Moody's Investors Service, Fitch Ratings, and Standard & Poor's -- to rate TALF securities, the Fed is relying on firms that failed to warn financial markets of the shaky credits that ended up in default and triggered the financial collapse.

Rating TALF securities could steer as much as $400 million in business to the three ratings agencies, Blumenthal has said.

Bernanke in his April 13 letter acknowledged the ratings agencies' blemished track records.

"The ratings methods employed by major NRSROs (nationally recognized statistical ratings organizations) for asset-backed securities have exhibited significant shortcomings," he said.