Bitcoin registered its biggest monthly decline in more than seven years as investors reevaluate the prospects of digital money following last year’s euphoria.

The biggest cryptocurrency dropped 6.1 percent to $3,930 on Friday, bringing its monthly loss to 37 percent. That’s the steepest drop since August 2011, when the token tumbled 39 percent to $8.20. Bitcoin surged to a record $19,511 in December 2017.

“It’s been a horrible bear market in tokens,” Galaxy Digital Holdings Ltd. founder Michael Novogratz said Friday during a conference call recapping his company’s third-quarter results.

Other leading digital currencies extended their slide. Ether declined about 3 percent to $111, bringing its monthly loss to 43 percent. XRP slumped 4.1 percent to 36 cents, pushing its monthly loss to 21 percent.

“Part of the sell-off is because, I think, the SEC got tough on a few fraudulent ICOs," Novogratz said. “People got very nervous.”