Bitcoin has gained a lot of fans recently, but Goldman Sachs CEO Lloyd Blankfein is not one of them.
In an interview with CNBC's Kayla Tausche, he said that "maybe bitcoin is a kind of a bubble," adding: "I don't like it. I'm not comfortable with it."
Blankfein's reason for not trusting the cryptocurrency is simple, he said: "I'm kind of an old dog to be absorbing that kind of a new trick."
Bitcoin has soared more than 600 percent this year. On Thursday, the cryptocurrency traded down 3.9 percent at $7,172.80, but remained near a record high.
The digital currency has already been embraced by some of Wall Street's most well-known figures, including investing legend Bill Miller. It has been criticized, however, by Blankfein's peers on Wall Street in JPMorgan Chase CEO Jamie Dimon and BlackRock CEO Larry Fink.
In September, Dimon referred to bitcoin as a "fraud," adding "it's worse than tulip bulbs. It won't end well." Last month, Fink said bitcoin was an "index of money laundering."
But Blankfein did not say the digital currency would fail, noting that "the list of things that are conventional today that I use every day that I thought would never make it is a very long list."
"If it works, I say to myself, 'Hmmm, maybe that was a natural progression from hard money to fiat money to consensus money.' So who's to say."