An area chart showing the six largest for-profit health insurers' revenue as a share of U.S. health spending from 2011 through 2023. The share has grown steadily from 9.7% in 2011 to a projected 29.1% in 2023. UHG and CVS/Aetna make up the largest portion of that share, followed by Cigna, Elevance, Centene, and Humana.