There is one stock he has never sold since buying in 1991, though: American Express ( AXP -0.20%). Buffett owns over 20% of the credit card issuer and bank, making it the second-largest position in the Berkshire Hathaway portfolio. The position trades at a value of $40 billion as of this writing.

Warren Buffett has been on a selling spree and recently trimmed his two biggest holdings: Apple and Bank of America. Buffett caught many investors by surprise when he trimmed his Apple position,

Warren Buffett, the legendary investor and chairman of Berkshire Hathaway BRKa.N, has made further preparations for giving away his fortune after his death. Buffett, 94, plans to donate 99.5% of his remaining wealth,