Bitcoin fell below $12,000 as predicted by experts

Bitcoin plunged by a quarter to below $12,000 on Friday as investors dumped the cryptocurrency in manic trading after its blistering ascent to a peak close to $20,000 prompted warnings by experts of a bubble.

It capped a brutal week that had been touted as a new era of mainstream trading for the volatile digital currency when bitcoin futures debuted on CME Group Inc, the world's largest derivatives market on Sunday.

Friday's steep fall bled into the US stock market, where shares of companies that have recently lashed their fortunes to bitcoin or blockchain - its underlying technology - took a hard knock in early trading.

The biggest and best-known cryptocurrency had seen a staggering twentyfold increase since the start of the year, climbing from less than $1,000 to as high as $19,666 on the Luxembourg-based Bitstamp exchange on Sunday and to over $20,000 on other exchanges.