"I can say nearly with certainty that cryptocurrencies will come to a bad end", Buffett.
The hard-driving Buffett, who has been reluctant to name a successor, said in the past that Berkshire's board knows who would take over if something were to happen to him. But I know this: "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.
The billionaire founder and CEO of Berkshire Hathaway named two senior executives - Greg Abel and Ajit Jain - to the company's board on Wednesday, while also appointing each of them to run large portions of the firm.
"They've both got Berkshire in their blood", Buffett said.
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He then shared his opinion that he didn't think Winfrey would run but that she "would be a lot of fun". "I like Oprah. It was very nice... "I think it is something that Oprah would have to feel and sense for herself".
Abel, now chairman and CEO of Berkshire Hathaway Energy, will assume the role as vice chairman of non-insurance business operations. Jain joined in 1986 and now serves as Executive Vice President of National Indemnity Company with overall responsibility for leading Berkshire's reinsurance operations.
"We don't own any, we're not short any, we'll never have a position in them", he said.
Bitcoin was marginally lower at 14,426 USA dollars in afternoon trading on Wednesday, according to prices listed by Coindesk. The Bitcoin price sank only slightly to about $14,400, while the price of Ethereum, the second most valuable cryptocurrency, rose to more than $1,300.
Buffett's comments come a day after JPMorgan Chase Chief Executive Jamie Dimon said he regrets calling bitcoin a fraud, referring to comments he made at a banking conference in September.