Further growth of cryptocurrencies is being hindered by potential new US tax reporting requirements.
Luno said the recent market rally, especially on Bitcoin, has now stalled because of the infrastructure bill passed by the Senate.
Earlier, CoinGecko reported that the value of more than 8,800 tokens rose 55% to $ 1.95 trillion from July lows, thanks to the recent buying pressure in both Bitcoin and Ether.
But the failure to change the proposed tax reporting rules, which are projected to generate about $ 28 billion in revenue, threatens the climb to $ 2 trillion market value.
Nevertheless, bullish traders are still not intimidated as forecasts say Bitcoin could hit $ 100,000.
Data on Thursday shows that Bitcoin lost 3.2% and fell to $ 44,100. Ethereum and other cryptocurrencies followed shortly.
But prior to the rebound in the past three weeks, the crypto market was overwhelmed by austerity measures in China, as well as concerns over the environmental impact of the energy required to create coins and process transactions.
The theft of $ 610 million in the emerging decentralized financial sector also highlighted security risks, even though the hackers returned about half of the money stolen.