But he says he would not take a short position on bitcoin futures.

"When it happens or how or anything else, I don't know," the billionaire Berkshire Hathaway chief says.

Warren Buffett tells CNBC the recent craze over bitcoin and other cryptocurrencies won't end well.

Billionaire investor Warren Buffett told CNBC on Wednesday the recent craze over bitcoin and other cryptocurrencies won't end well. "In terms of cryptocurrencies, generally, I can say with almost certainty that they will come to a bad ending," the chairman and CEO of Berkshire Hathaway said. "When it happens or how or anything else, I don't know," he added in an interview on CNBC's "Squawk Box" from Omaha, Nebraska. "If I could buy a five-year put on every one of the cryptocurrencies, I'd be glad to do it but I would never short a dime's worth."

Also on the show, Buffett's right-hand man, Charlie Munger, also blasted frothiness in bitcoin — and in venture capital funding. Earlier Wednesday, the Omaha-based conglomerate announced the appointment of two new vice chairs. Gregory Abel, 55, will be vice chair of non-insurance businesses. Ajit Jain, 66, will be vice chair of insurance operations. Buffett said he would not take a short position on bitcoin futures. "We don't own any, we're not short any, we'll never have a position in them," he said.

David A. Grogan | CNBC

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