Overall Medicare Advantage program enrollment increased 7.6 percent between February 2016 and February 2017, to 19.6 million.
UnitedHealth Group Inc. accounted for about 800,000 of the 1.4 million additional enrollees, according to a new analysis from Portland, Maine-based Mark Farrah Associates.
Enrollment at UnitedHealth's Medicare Advantage plans jumped 22 percent, to 4.6 million.
The Medicare Advantage program gives private insurers a chance to offer an alternative to traditional Medicare coverage for people who sign up for both Medicare Part A hospitalization coverage and Medicare Part B outpatient and physician services coverage.
The Medicare Advantage program now covers 34 percent of the 58 million people who have Medicare coverage.
Mark Farrah Associates created the new program enrollment analysis using data from the Centers for Medicare & Medicaid Services. Mark Farrah has posted the analysis here.
UnitedHealth increased the number of Medicare Advantage enrollees it serves faster than any other issuer, and it also led in terms of market share. In February, it served about 24 percent of Medicare Advantage program enrollees.
