COLUMBUS, Ohio — Ohio’s attorney general has sued the three credit ratings agencies alleging that they gave unjustifiably high ratings to mortgage-backed securities that lost at least $457 million for five Ohio public pension funds.

Attorney General Cordray filed the suit Friday in U.S. District Court in Ohio. He said that Standard & Poor’s, Moody’s Investors Service, and Fitch Ratings assured the pension funds that mortgage-backed securities had the highest ratings and lowest risk.