Former Wells Fargo Chairman and CEO Dick Kovacevich told CNBC on Tuesday that he believes bitcoin is a scam.

"I think it's a pyramid scheme. It makes no sense. I'm just surprised it isn't even lower," he said on

Kovacevich joins a growing list of bankers who have denounced the crytopcurrency craze.

Jamie Dimon, chairman and CEO of J.P. Morgan Chase, recently backpedaled a bit on his earlier criticisms on bitcoin.

In September, Dimon called bitcoin a fraud.

In a Fox Business interview last week, he said he regrets making that comment, but added he's "not interested that much in the subject at all."

Kovacevich does not see bitcoin as an outright fraud.

"There's no fraudulent thing going on. It's just a pyramid scheme," he said. "You're betting that somebody is going to buy it. And some people have been right."

"The fundamentals make no sense," he contended.

Bitcoin tumbled to a six-week low early Tuesday, falling below $12,000 for the first time since Dec. 5, according to CoinDesk, before paring some of those losses.

Comments from South Korea's finance minister renewed concerns about a crackdown in one of the largest markets for digital currency trading.

Despite cold water from the likes of Kovacevich and Dimon, bitcoin bulls such as Saxo Bank crypto analyst Kay Van-Petersen see amazing upside. Van-Petersen predicts $100,000 this year.