Billionaire investor Warren Buffett isn't joining in on the bitcoin rallying cry. 

"I can say almost with certainty that they will come to a bad ending," the CEO of Berkshire Hathaway Inc. (BRK.A) - Get Report said of cryptocurrencies in an interview with CNBC on Wednesday, Jan. 10.

"If I could buy a five-year put on every one of the cryptocurrencies I would be glad to do it," Buffett said. "But I would never short a dime's worth."

Buffett clarified that he's not interested in getting into the futures market for bitcoin, which launched on Cboe Global Markets (CBOE) - Get Report and CME Group Inc. (CME) - Get Report last month. 

"I get in enough trouble with things I know something about," Buffett said. "Why in the world should I take a long or short position on something I don't know anything about?"

Buffett previously called bitcoin a "mirage" in 2014. He's joined in his skepticism by JPMorgan Chase & Co. (JPM) - Get Report CEO Jamie Dimon, who called bitcoin a "fraud" in October. While Dimon scaled back his criticism some he still remains uninterested in piling in on the cryptocurrency.

Buffett's second-in-command at Berkshire, Charlie Munger, agreed with Buffett, too. In the same CNBC interview, Munger said bitcoin and other cryptocurrencies were, in fact, bubbles.

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