Bitcoin is in the middle of an astounding price drop, reaching prices as low as $3,520 in recent days and wiping out all gains from coins purchased this year. As of press time, the price was hovering around $3,900, a roughly 40 percent drop from two weeks ago. The result is the worst price drop since April 2013, refreshing old doubts about the soundness of bitcoin as an investment vehicle.

It’s a dramatic turn from 2017, when the value passed $15,000 in the beginning of December to peak just below $20,000. After that, prices plummeted. By January of this year, it lost half of its peak value, and continued to drop. The drop has been particularly dramatic in the last couple of weeks.

The price drop is likely the result of a series of forks this year, which produced parallel currencies like Bitcoin Cash. A planned fork of Bitcoin Cash took place on November 15th, and was accompanied by considerable angst from traders ahead of time. CoinDesk notes that Bitcoin Cash and several other bitcoin forks have reported losses of more than 10 percent in a 24 hour period.