Blue Cross Blue Shield Association

Blue Cross Blue Shield Association covers 115 million Americans—one in three—which is 4.5 times the membership of #5 Humana and surpasses any single for-profit competitor by 40 million lives. The federated network's 33 independent plans collectively processed 1.2 billion claims in 2025, achieving a 95% claims payment accuracy rate that is 3% above the national average. Its nonprofit structure allows 82% of premiums to return as medical benefits, outpacing UnitedHealth's 76% payout ratio.