Warren Buffett is preparing to step down. He just revealed some of his final stock picks.

It seems Warren Buffett has healthcare on his mind as he approaches retirement. The 94-year-old investor's Berkshire Hathaway scooped up just over 5 million shares of UnitedHealth stock last quarter, securing a stake in the health insurer worth $1.6 billion at the end of June. The new holding was revealed in the conglomerate's quarterly portfolio update, known as a 13F, on Thursday. Business Insider tells the innovative stories you want to know Business Insider tells the innovative stories you want to know ...