Amid widespread cryptocurrency selling, bitcoin fell 5% on Friday to its lowest level since late September, dropping below $41,000.

The world's largest cryptocurrency has lost more than 40% since hitting a record high of $69,000 in November. And the volatility that has characterized it since its birth 13 years ago remains stubbornly present. Bitcoin was lately down 3.7% after hitting $40,938, its lowest since Sept. 29. The global computing power of the bitcoin network has fallen sharply following the internet shutdown in Kazakhstan, as an uprising hit the country's growing cryptocurrency mining industry. Bitcoin also came under pressure after the minutes of the US Federal Reserve's latest meeting, released on Wednesday, appeared to be tilting towards more aggressive policy action, sapping investors' appetite for riskier assets. Ether, the second-largest token by market cap, fell as much as 8.6% to $3,114, its lowest since Oct. 1.