The U.S. Dept. of Justice recently filed a lawsuit against...

...Anthem, Inc., alleging that from 2014 to 2018, the company knowingly submitted inaccurate billing codes to obtain higher risk adjusted payments from the Medicare Advantage program. Anthem replied in a statement to news outlets that "the government is trying to hold Anthem and other Medicare Advantage plans to payment standards that CMS does not apply to original Medicare." As of March 2020, the insurer currently serves 1,288,321 Medicare Advantage members.

From AIS's Directory of Health Plans