It was a great weekend for bitcoin.

Last week, we saw the price of a single bitcoin slowly creep up to reach $467.50 on Thursday night. But that was nothing compared to Friday, when the price of the digital currency surged by as much as 15 percent and briefly reached $530, according to Quartz. This is bitcoin’s highest price since August 2014, when it was traded by about $532.

CoinDesk had slightly lower values for the digital currency. According to the site’s price index, bitcoin hit a high of $479.39—a value not seen since September 2014, when bitcoin went on a free fall from more than $1,000 per single bitcoin.

The verdict is still out on the exact reason behind the surge.