Bitcoin is plunging again and has now lost a third of its value this week

Kim Kyung-Hoon | Reuters

A logo of Bitcoin is seen on an advertisement of an electronic shop in Tokyo, Japan September 5, 2017.

Bitcoin prices fell 8 percent on Friday, dipping below $3,000, as it continues quite a tumultuous week.

The cryptocurrency traded at $2,970 and fell as low as $2,951.15, its lowest level since early August. Over the past week, bitcoin has lost more than 35 percent of its value.

Bitcoin one-week chart

Source: Coindesk.com

Despite its massive drop over the past seven days, however, bitcoin is still up nearly 200 percent for the year. By comparison, the S&P 500 is up 11.5 percent in 2017.

Investors have been dumping bitcoin this week as Chinese authorities ramp up their crackdown on cryptocurrency exchanges. BTC China, one of the biggest exchanges in the country, said it will stop all trading by Sept. 30.

The announcement comes nearly two weeks after Chinese regulators banned fund raising through initial coin offerings. Chinese financial media outlet Yicai Global also reported China plans to shut down all bitcoin exchanges by month’s end.

The cryptocurrency this week also received flack from JPMorgan CEO Jamie Dimon, who called bitcoin a “fraud” and said, “It won’t end well. Someone is going to get killed.”