Why 'Shark Tank's' Kevin O'Leary Doesn't Believe in Bitcoin

Investor Kevin O'Leary doesn't believe in bitcoin in nearly the same way his "Shark Tank" co-host Mark Cuban does, calling the cryptocurrency a "nothing-burger" in a video published on YouTube Tuesday. 

O'Leary said his trepidation stems partially from the fact that the cryptocurrency isn't accepted everywhere.

"Bitcoin is a nothing-burger, a giant nothing-burger," said O'Leary, "because you don't have every institution willing to play ball with it. I can't get consistency with any single regulator in endorsing bitcoin for me to do a significant transaction."

O'Leary went on to note that "it's getting better, but it's not something every regulator in every market [supports]."

O'Leary's colleague Mark Cuban has been one of the staunchest bitcoin supporters, with the Dallas Mavericks owner even allowing consumers to use the digital currency at Mavs games.

Earlier this week, Cuban compared the recent volatility in cryptocurrency prices to the 1990s dot-com bubble, predicting that bitcoin, ethereum and "a few others" would be equivalent to the tech giants who survived that bubble. 

"Watching the cryptos trade, it’s EXACTLY like the internet stock bubble," Cuban wrote in a tweet. "EXACTLY. I think btc, eth, a few others will be analogous to those that were built during the dot-com era, survived the bubble bursting and thrived, like AMZN, EBay, and Priceline. Many won’t."

Last week, the total market capitalization for all cryptocurrencies rose above $1 trillion as bitcoin led a dramatic jump in valuation.

On Sunday and Monday, however, bitcoin posted its worst two-day drop since March, sliding as much as 21% as investors moved to perceived safe-haven assets -- in this case not bitcoin.

On Tuesday afternoon, Bitcoin was trading around $34,391 after falling to about $30,000 on Monday.