In the first enforcement action of its kind, Moody’s Investors Services Inc. has agreed to pay $16.25 million to settle charges that it failed to adopt adequate internal controls and to apply clear and consistent credit rating symbols.

It marked the first time the U.S. Securities and Exchange Commission has filed an enforcement action involving rating symbol deficiencies, according to a statement from the SEC. Moody’s, part of New York-based Moody’s Corp., is one of the nation’s largest credit ratings agencies. It neither admitted nor denied the charges in Tuesday’s orders.