Bitcoin touched below US$6,000 and dozens of smaller digital tokens including Ether retreated as this month’s sell-off in cryptocurrencies showed few signs of letting up.

The largest digital currency fell as much as 6.2 per cent to US$5,887, the lowest level since June, before paring some of the drop, according to Bloomberg composite pricing. Ether sank as much as 13 per cent, while all but one of the 100 biggest cryptocurrencies tracked by Coinmarketcap.com recorded declines over the past 24 hours.

The total market capitalization of virtual currencies dropped to US$193 billion. That’s down from a peak of about US$835 billion in January.

“Most cryptocurrencies have been overvalued for a very long time,” said Samson Mow, chief strategy officer at blockchain developer Blockstream Corp. “It’s hard to pin this move on any particular factor, but it feels like the opposite of last year when money piled in as people felt FOMO. Now it’s piling out as they sense panic.”

While cryptocurrencies rallied in July on hopes that a Bitcoin-backed exchange-traded fund would attract new investors, U.S. regulators have yet to sign off on multiple proposals for such a product. The letdown has coincided with growing concern that entrepreneurs who raised crypto-denominated funds via initial coin offerings are now cashing out of holdings such as Ether, the token for the Ethereum blockchain that is a popular platform for crypto projects.

“The big story in the market today is the huge weakness in Ethereum,” Timothy Tam, chief executive officer of CoinFi, a cryptocurrency data analysis company, said in a phone interview. “Bitcoin has held up relatively well versus Ethereum. It’s still quite weak versus the U.S. dollar.”

At the height of Ether’s rally last year, the digital coin comprised 32 per cent of cryptocurrency market capitalization, coming within striking distance of Bitcoin’s 39 per cent. Ether now makes up about 14 per cent, while Bitcoin accounts for 54 per cent after falling less quickly than its smaller peers, according to Coinmarketcap.com.

“ICOs that have raised a lot of money are really feeling a lot of pain” as their crypto holdings lose value, Tam said.

Ether has tumbled about 40 per cent this month, while Bitcoin has dropped about 26 per cent.

It’s unlikely that recent global market turbulence, fueled by Turkey’s currency crisis, is impacting cryptocurrencies, said James Quinn, head of markets at Kenetic, a blockchain company with investment and advisory businesses.

“Correlations historically have been extremely low between cryptocurrencies and other asset classes,” he said in a phone interview from Hong Kong. “Which is one of the reasons why there is interest in this space and why people want to make an allocation in this space.”

Still, anyone expecting Bitcoin to provide a haven from turbulence in global markets will have been disappointed. The cryptocurrency’s slide against the dollar this month is almost as big as the Turkish lira’s 25 per cent slump.