UnitedHealth Group (UNH) stock has been a major underperformer in 2025, with UNH down nearly 50% year-to-date amid rising medical costs, regulatory scrutiny, and a Department of Justice investigation into billing practices.

Buffett, through Berkshire, bought more than 5 million shares of the managed care company, worth an estimated $1.6 billion. Meanwhile, Michael Burry, who became famous in the book and movie The Big Short for his bet against subprime mortgages, bought 20,000 shares. Billionaire David Tepper also increased his stake in the name during the quarter.