Medicare Advantage, a fast-growing private alternative to original Medicare, has enrolled more than 26 million people. Humana Inc. is one of the largest of these insurers. While popular with seniors, Medicare Advantage has been the target of multiple government investigations.

FILE – This Nov. 8, 2018 file photo shows a page from the 2019 U.S. Medicare Handbook in Washington. The federal government is giving insurers who offer Medicare Advantage plans more leeway to pay for things they’d ordinarily never cover. (AP Photo/Pablo Martinez Monsivais, File)