Bitcoin pulled back after making a run at $20,000 on Tuesday amid skepticism over the cryptocurrency’s intense rally.

Prices rose to an intraday record of $19,914.33 and then sharply retreated. In an interview with Bloomberg Television, Gary Cohn, a former economic chief to Donald Trump, said the token “lacks some of the basic integrity of a real market” and could eventually fail.

“Part of the integrity of a system is knowing who owns it and knowing who has it and knowing why it’s being transferred,” said Cohn, the ex-chief of Goldman Sachs Group Inc. “The Bitcoin system today has no transparency to it. So there are a lot of people that question, why would you need a system that does not have an audit trail.”

Bitcoin was down 3.9% at $18,624.18 as of 8:25 a.m. in New York. The digital currency is still up almost 10% this week. The broader Bloomberg Galaxy Crypto Index slid 3.9% on Tuesday.

Marcus Swanepoel, chief executive of London-based crypto exchange Luno, said Bitcoin will likely enter the $20,000 to $25,000 range before a significant selloff. Then “it’s likely we’d see a 20% to 30% pullback. This is a predictable pattern and there is no reason to not expect it.”

Worth less than $1 back in 2010 when it was touted as currency for purchases, Bitcoin has amassed proponents who argue that its strictly controlled supply and wider investor base show it’s become a store of value. Critics, however, say this year’s 160% rally is a bubble that can’t be supported by claims that digital assets should diversify portfolios and take flows from gold.

Bitcoin’s surge this week “is likely a result of major institutional investors joining the bandwagon and purchasing a portion of BTC’s limited supply in the midst of a bull run,” said Gunnar Jaerv, chief operating officer of Hong Kong-based custodian First Digital Trust.