Bitcoin went on a tear in early morning trading earlier today, popping up to above $4,900 and reminding some investors of the good old days of 2017.

The currency is still trading up above 15 percent at $4,782.60, which is a healthy jump for the cryptocurrency (which had been languishing at around $4,000 for the past three months). Indeed, the price was up over 25 percent over the previous month, according to Coinbase.

Bitcoin’s surge also sent the other top cryptocurrencies, including Ethereum and Litecoin, soaring.

No one can quite pin down the reason for the currency’s surge, given the string of bad news that has unspooled around the cryptocurrency business in the past few weeks.

Despite an April Fool’s Day article to the contrary, the Securities and Exchange Commission still has not approved an exchange-traded fund that would track to the cryptocurrency. And one of the big public offerings that was supposed to showcase the strength of the market seems to have been shelved as Bitmain has not renewed its application for a public listing on the Hong Kong Stock Exchange.

One analyst had a simple reason for the Bitcoin price surge; a big, $100 million order for the cryptocurrency that was placed overnight and spread across the U.S. exchanges Coinbase and Kraken and Luxembourg’s Bitstamp.

“There has been a single order that has been algorithmically-managed across these three venues, of around 20,000 BTC,” Oliver von Landsberg-Sadie, chief executive of cryptocurrency firm BCB Group, told Reuters in an interview.