Billionaire Bill Ackman has wanted to use Howard Hughes Holdings to create a modern-day Berkshire Hathaway. After two unsuccessful attempts at making a deal, Ackman and Howard Hughes have agreed to terms.

"You're losing one of the most esteemed investors one could argue of all time," a source said of investors' reaction to Buffett's plan to step down.

Buffett talked about U.S. trade, the stock market and his own future at Berkshire Hathaway's annual shareholder meeting. Here are the highlights.