There’s no question that many long-term shareholders of Berkshire Hathaway (NYSE:BRK-B) have stuck around for so long because of the great Oracle of Omaha, Warren Buffett. Indeed, Buffett’s legendary leadership and incredible stock-picking skills have been big reasons to justify paying a bit of a premium for Berkshire Hathaway stock at any given moment in

Actually, Buffett has invested roughly $90 billion in nine companies that are heavily focused on AI. Here they are -- and which one is the best of the bunch.

Buffett touches on the importance of return on investment in his 1992 annual letter to Berkshire Hathaway, noting that "growth benefits investors only when the business in point can invest at incremental returns that are enticing -- in other words, only when each dollar used to finance the growth creates over a dollar of long-term market value."