The company has said in regulatory filings that investigations, audits and reviews by a dozen different government agencies are currently underway.

Medicare practices sent the stock diving Thursday to a five-year low. The Justice Department is looking into potential Medicare fraud by the health insurer, according to a report by the Wall Street Journal,

UnitedHealth Group, one of America’s largest health insurers, is facing a storm of challenges—from a criminal investigation to a leadership shake-up—that have rattled markets and erased billions in shareholder value.