Bitcoin briefly dipped below $3,000 on Friday during a tumultuous week of trading.

The cryptocurrency fell as low as $2,951.15, its lowest level since early August, before rebounding. It traded 2.99 percent higher at $3,322.74 in New York. For the week, however, bitcoin has lost about 20 percent of its value.

Bitcoin this week

Source: Coindesk.com

Despite its massive drop this week, however, bitcoin is still up about 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 caught flak from JPMorgan CEO Jamie Dimon, who called bitcoin a “fraud” and said, “It won’t end well. Someone is going to get killed.”