Bitcoin prices plunged about 8 percent Thursday after one of the biggest exchanges in China said it will shut down its operation.

The cryptocurrency traded at $3,571.23 at 11:16 a.m. in New York, far below an all-time high of $5,013.91 set earlier this month.

BTC China said in a tweet Thursday that it will close down its operations by Sept. 30 as Chinese authorities crack down on cryptocurrencies.

China is tightening its grip on the burgeoning currency. On Sept. 4, Chinese media outlet Caixin reported that regulators banned companies from raising money through initial coin offerings (ICOs), referring to them as an unauthorized fundraising tool that may involve financial scams.

Since then, bitcoin has lost more than 20 percent of its value.

Bitcoin since Sept. 4

Source: Coindesk

“This all because of China. Chinese investors have until September 30th to get their money out of exchanges before they close,” Brian Kelly, CEO and founder of BKCM and a CNBC contributor, said in an email. “This is a market structure drop and not a drop on fundamentals, therefore this is a buying opportunity.”

It’s been a rough month for Bitcoin. Just two days ago, JPMorgan CEO Jamie Dimon called the cryptocurrency a “fraud,” adding “it won’t end well.”

“It’s worse than tulip bulbs. It won’t end well. Someone is going to get killed,” Dimon said at a banking industry conference organized by Barclays. “Currencies have legal support. It will blow up.”