The National Credit Union Administration is fighting a subpoena by Standard & Poor’s Financial Services LLC related to the Justice Department’s $5 billion case against the credit ratings agency.

NCUA, which regulates federally insured credit unions, is the latest government agency fighting discovery in the case, according to S&P. The Justice Department has accused S&P of inflating ratings on residential mortgage-backed securities and other high-risk investments before the 2008 financial crisis.