Credit raters failed to follow their own criteria, allowed research analysts to discuss fees with issuers and kept incomplete records, according to a report from the U.S. Securities and Exchange Commission.

The SEC’s Office of Credit Ratings didn’t name specific companies in its third annual examination report released Tuesday, distinguishing them as either larger firms, such as McGraw-Hill Co.’s Standard & Poor’s, Moody’s Corp.’s Moody’s Investors Service and Fitch Ratings, or smaller ones, including Kroll Bond Rating Agency Inc. and DBRS Inc. The regulator also didn’t identify firms in its two prior reports.

One large company and five smaller firms didn’t follow their own methodologies in determining ratings, the SEC said in its report on Nationally Recognized Statistical Rating Organizations or NRSROs. Four smaller companies failed to separate analytical and business divisions, and all large and six smaller firms didn’t keep adequate records related to ratings actions.

The SEC began filing its annual examination reports after Congress passed the Dodd-Frank financial reform law in 2010, instructing regulators to stop relying on ratings and increase oversight of the companies that issue them. The Financial Crisis Inquiry Commission blamed the firms for awarding top credit grades to risky mortgage bonds, helping ignite the worst recession since the Great Depression when defaults soared.

The larger firms provided 96.5 percent of all ratings at the end of last year, falling from 98.8 percent at the end of 2007, according to a separate SEC report. Sales at the top three firms accounted for about 94.7 percent of all NRSRO revenue last year, up from 94 percent in 2011.

In 1936, the Office of the Comptroller of the Currency banned banks from holding bonds that were below investment grade. The SEC began using ratings in its rules in 1975, specifying that the only companies whose grades could be used were S&P, Moody’s and Fitch. Ten firms now carry the NRSRO designation.