By the numbers. 25 largest national managed-care organizations. Ranked by total HMO enrollment (as of Jan. 1, 2001).
D003258:Consumer Behavior / Q000706:statistics & numerical data*; D019538:Health Care Surveys; D006279:Health Maintenance Organizations / Q000145:classification* / Q000706:statistics & numerical data*; D020407:Internet; D014481:United States