Regulators are investigating Standard & Poor’s over some of its ratings, according to a regulatory filing by the S&P’s parent company.

The McGraw-Hill Companies Inc., which owns the S&P ratings agency, says the Department of Justice and the Securities and Exchange Commission are investigating whether the S&P broke federal laws when rating certain investments.

McGraw-Hill says the accusations are unfounded and that it will vigorously defend itself.

The company didn’t give details, and analysts didn’t ask about the investigation in a conference call about McGraw-Hill’s second-quarter earnings. But ratings agencies like S&P have been accused of giving improperly high ratings to some investments made of mortgage loans that had been packaged together and sold to investors, helping fuel the financial crisis.

Last September, the SEC told the ratings agency it was considering filing a charge over S&P’s ratings on a particular investment offering from 2007, just before the meltdown in the housing market imploded.

Read More: Yahoo Finance News