Bitcoin has extended its recovery in holiday-thinned trading, rising 10 percent to be up more than a third from last week’s lows of below $12,000.

Bitcoin, the world’s largest, best-known cryptocurrency, fell nearly 30 percent at one stage on Friday to $11,159.93 and, despite a late recovery, had its worst week since 2013. At 04:45 GMT on Tuesday, it was quoted at around $15,049 on the Luxembourg-based Bitstamp exchange.

The digital currency had risen around twentyfold since the start of the year, climbing from less than $1,000 to as high as $19,666 on December 17 on Bitstamp, and to over $20,000 on other exchanges. But it has posted heavy declines since.

While bitcoin investors and analysts believe the decline in its value was a natural correction after a heady rise in prices, there have been further warnings from market regulators and central banks.

“There is no right current price which would reflect the right current valuation,” said Andrei Popescu, Singapore-based cofounder of COSS, which describes itself as a platform that encompasses all features of a digital economy based on cryptocurrency.

“Taking profit is right, while buying into a long-term projection is also right. You don’t have to be right in this market, just less wrong than the rest,” Popescu said.

Singapore‘s central bank last week issued a warning against investment in cryptocurrencies, saying it considers the recent surge in their prices to be driven by speculation and that the risk of a sharp fall in prices is high.

Prices of rival cryptocurrencies, which slid along with bitcoin last week, have also recovered, with Ethereum, the second-biggest cryptocurrency by market size, quoted at around $771, up from Sunday’s low of $689 but still far from highs of around $900 last week.

Tel Aviv Stock Exchange

Israel’s markets regulator said on Monday he will propose regulation to ban companies based on bitcoin and other digital currencies from trading on the Tel Aviv Stock Exchange (TASE).

Shmuel Hauser, chairman of the Israel Securities Authority (ISA), told the Calcalist business conference he will bring the proposal to the ISA board next week. If approved, it would be subject to a public hearing and then the TASE bylaws would need to be amended.

“If we have a company that their main business is digital currencies we would not allow it. If already listed, its trading will be suspended,” Hauser said, adding the ISA must find the appropriate regulation for such companies.

“We feel that the prices of bitcoin behave like bubbles and we don’t want investors to be subject to that volatility and uncertainty,” Hauser said. “There is an importance to signal to the market where things are … Investors should know where we stand.”

Earlier this month, Hauser had said bitcoin-based companies would not be included in TASE indexes and that there was a need for a suitable regulatory framework for such instruments, given that the global market value of all digital currencies grew in 2017 to $300bn from $18bn.

The proposal will likely be the last for Hauser, who will step down next month after 6.5 years as ISA chief. “But once it’s on its way it will continue to be pursued,” said Hauser, who will be replaced by Anat Guetta. He said he hopes she will promote easing capital gains taxes and a focus on regulatory enforcement.