Barron’s estimates that Berkshire could owe more than $20 billion of taxes on the sales of Apple stock, which likely accounted for nearly all of the $97 billion of taxable gains

Berkshire started to invest in Coca-Cola in 1988. It hasn't bought or sold any more shares over the past 12 years, but its $26 billion stake in the beverage leader accounts for 8.5% of its entire portfolio and ranks as its fourth-largest investment.

When you think of artificial intelligence (AI) stocks, you may not automatically think of Warren Buffett. The Oracle of Omaha, as he's often called, has made a fortune through investing in the stock market, but his choices generally aren't tech stocks or companies focused on a newish or up-and-coming field.