(Bloomberg) -- Cryptocurrencies sold off Friday as a crash in tokens used in decentralized-finance applications accelerated, deflating the value of some once-hot investments by more than 50%.

DeFi coins, which gained popularity this year to become one of the hottest sectors in the market, came back down to earth Friday. Tokens including Galaxium, IDALL, Crypto Village Accelerator and MoonJuice have each lost more than 50% over the past 24 hours, according to data from CoinMarketCap.com. More established ones, such as Uniswap -- which is one of the best-known in the space -- lost roughly 7%, while Chainlink retreated 9%.

“DeFi tokens have been the epicenter of questionable valuations in this crypto bull rally, similar to what was seen in the ICO-craze of 2017,” said Stephane Ouellette, chief executive and co-founder of FRNT Financial. “Untested protocols, some of which have lost millions in customer assets continue to trade at valuations in the 100 millions or billions. It’s clearly not sustainable and is an existential risk to the prices of tokens representing promising projects in the space.”

The broader crypto market also lost ground, with Bitcoin, the original cryptocurrency, dropping as much as 3.1% on Friday to trade around $36,564. Other coins also retreated, with the Bloomberg Galaxy Crypto Index -- which tracks Bitcoin, Ether and Litecoin, among others -- dropping 3.5% at one point. That’s its lowest point since early June.

DeFi apps are designed to let people lend, borrow, trade and take out insurance directly from each other, without use of intermediaries such as banks. The space -- though it’s been plagued by hacks, fraud and a copy-and-paste coding culture -- boomed earlier in the year but came crashing down this week.

The selloff was exemplified by the DeFi Titanium token, which in one day went from being valued around $60 to $0, a rare feat even for the famously volatile crypto space. Famed mogul Mark Cuban had invested, telling Bloomberg News earlier this week that though it represented a small percentage of his crypto portfolio, the wipe-out “was enough that I wasn’t happy about it.”

To Keith Lerner, the chief market strategist at Truist Advisory Services, the drawdown means many investors, now stuck with losing positions, are second-guessing their investments.

“With crypto in general, it had moved up so quickly, some of it has cooled off,” Lerner said. “Most people who got in this year are in a losing position. That probably takes off a little bit of the short-term shine.”

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