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.

Warren Buffett has made his billions largely through investing.

Those challenges are clearly preventing the bulls from rushing back to Berkshire, but I think its stock still looks reasonably valued.