Warren Buffett said he would be "surprised" if stock prices fell 50 percent from their current levels.
He predicted there will be another financial crisis in the years ahead, but he doesn't think it will happen anytime soon.
"Humans will behave in crazy ways, both on the upside and the downside in the next 50 years. It's very unlikely they do it in the next few years because after something like 2008, once they get out of the emergency room, they're a little more careful for awhile."
Buffett said he's been bullish on the U.S. economy since the financial crisis in 2008, but he doesn't expect it to rapidly accelerate this year. Instead, he thinks it will continue its slow upward trajectory.
Buffett said he'd advise people to "stay away" from bitcoins because they are a "mirage" without any intrinsic value, although they are an efficient way to transfer dollars.
Buffett also said Berkshire Hathaway (BRK-A) has "almost entirely eliminated" its catastrophe insurance in the U.S. because rates have dropped too much.
Buffett said, "The rates came down dramatically and we do not regard the exposure as having come down dramatically."
Berkshire is still writing policies in Asia.
Asked about the controversy over faulty ignition switches in General Motors (GM) cars, Buffett said CEO Mary Barra has a "new chance" because she just started in the post but the company needs to tell the truth and act quickly to fix any problems.
He said his advice is to "Get it right, get it fast, get it out, get it over, but get it right first."
Buffett was appearing live on CNBC's " Squawk Box " with Dan Gilbert to promote their "Quicken Loans Billion Dollar Bracket Challenge with Yahoo Sports" in which anyone who correctly predicts the outcome of every game in the NCAA basketball tournament will win $1 billion.
(Read more: Buffett insures billion dollar bracket madness )
Buffett's Berkshire sold the insurance that will fund the prize in the extremely unlikely event someone wins it. Odds against winning can't be calculated precisely but estimates involve the word "quintillion."
-By CNBC's Alex Crippen. Follow him on Twitter: @alexcrippen