Bitcoin’s meteoric rise last year had many observers calling it one of the biggest speculative manias in history. The cryptocurrency’s 2018 crash may help cement its place in the bubble record books.

Down about 70 percent from its December high after sliding for a fourth straight day on Friday, Bitcoin is getting ever-closer to matching the Nasdaq Composite Index’s 78 percent peak-to-trough plunge after the U.S. dot-com bubble burst. Hundreds of other virtual coins have all but gone to zero — following the same path as Pets.com and other red-hot initial public offerings that flamed out in the early 2000s.

While Bitcoin has bounced back from bigger losses before, it’s far from clear that it can repeat the feat now that much of the world knows about cryptocurrencies and has made up their mind on whether to invest. Bulls point to the Nasdaq’s eventual recovery and say institutional investors represent a massive pool of potential cryptocurrency buyers, but regulatory and security concerns have so far kept most big money managers on the sidelines.

“You’ll have to see the market reverse before you see” institutions pile in, Peter Smith, chief executive officer of Blockchain Ltd., which introduced a crypto trading platform for professional investors on Thursday, said in an interview on Bloomberg Television.

Read more on how Bitcoin’s rally compared to history’s biggest bubbles.

Bitcoin declined as much as 4.2 percent to $5,791 on Friday, the lowest level since November, according to Bloomberg composite prices. The cryptocurrency recovered on Saturday in Asian hours, rising 8.6 percent to $6,397 at 11:35 a.m. in Tokyo, according to Bitstamp.

Still, Bitcoin is down around 55 percent this year, according to Bitstamp. Other coins including Ether and Litecoin slumped more, while the combined value of tokens tracked by CoinMarketCap.com declined to $236 billion. At the peak of crypto-mania, they were worth about $830 billion.

While it was difficult to find fresh catalysts for Bitcoin’s drop on Friday, hacks at two South Korean exchanges and a regulatory clampdown in Japan have weighed on sentiment in recent weeks. Regulators around the world have stepped up scrutiny of cryptocurrencies on concern that they’re a breeding ground for illicit activity including money laundering, market manipulation and fraud.

Lesser-known tokens have been hit the hardest. Dead Coins lists around 800 that are effectively worth nothing, while Coinopsy puts the tally at more than 1,000. Fewer than 4 percent of coins with market caps from $50 million to $100 million were successful or promising, according to a March analysis from ICO advisory firm Satis Group.

Bitcoin may not go to zero, but it’s “very much” a bubble, Robert Shiller, the Nobel laureate economist whose warnings about dot-com mania proved prescient, said in an interview with Bloomberg Television’s Tom Keene on Tuesday. Last year’s Bitcoin surge was “not a rational response,” he said.