In the context of the U.S. property and casualty or health insurance sectors, the "Big Three" can refer to different categories depending on the line of insurance. In health insurance, the largest dominant carriers are UnitedHealthcare, Anthem (Elevance Health), and CVS Health (Aetna). In major property and casualty personal lines, companies like State Farm, Berkshire Hathaway (GEICO), and Progressive lead market share.