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.

Berkshire Hathaway, Buffett’s investment group, disclosed it had bought 5 million shares of the healthcare company earlier in the year. That sparked a 14% Friday rally in a stock that has lost more than half of its value over the past 12 months.

Shares of UnitedHealth Group are surging before the market open Friday as Warren Buffett’s Berkshire Hathaway disclosed that it recently purchased shares of the beleaguered insurer.