Bitcoin hovers above $40,000 after a wild week that saw the cryptocurrency plunge 30% at one point

Bitcoin’s price hovered above the $40,000 level on Friday, as a comeback for the world’s top cryptocurrency was checked by worries around regulation.

The digital coin was up 1.7% at a price of $40,841 by 6 a.m. ET, according to Coin Metrics data. It bounced above the $42,000 mark Thursday as digital currencies attempted to rebound from a brutal sell-off earlier in the week.

Other cryptocurrencies were in the red Friday, with ether down 2.2% at $2,741, XRP off by 4.6% at $1.13 and litecoin falling 2.4% to $206. Dogecoin, a meme-inspired crypto supported by Tesla CEO Elon Musk, was down 2.6% at 39 cents.

Bitcoin’s gains were capped Friday after the U.S. Treasury Department said a day earlier that it would require any cryptocurrency transfer worth $10,000 or more to be reported to the Internal Revenue Service.

“Cryptocurrency already poses a significant detection problem by facilitating illegal activity broadly including tax evasion,” the Treasury said.