Shares of several medicare insurers including UnitedHealth Group Inc UNH, Humana Inc HUM and CVS Health Corp CVS are moving lower in Monday's after-hours session following reports that federal health authorities are planning new standards for auditing billings for companies that offer private Medicare plans. What Happened: According to a Bloomberg report, the U.S. Medicare agency planned to seek approximately $4.7 billion over 10 years in "clawback payments" from private insurers that managed plans under a new auditing rule. The rule reportedly finalized a 2018 proposal for auditing the private plans that administer programs for the agency in what aimed to recover "excessive payments based on exaggerated claims of patient illness," the report indicated. "Today we are taking some long overdue steps to move us in a direction of accountability," Xavier Becerra, Health and Human Services Secretary, reportedly said on a call with reporters.