IT takes a lot to startle fans of bitcoin, the digital gold of the moment. But Wednesday was, well, a lot - a wild run of exuberant peaks and white-knuckled declines that left even diehards breathless.

The dizzying rally in bitcoin, a bull market with few precedents in investing history, was abruptly interrupted by a market outage in the US that seemed to captivate Wall Street even more than the day's selloff in high-flying technology stocks. Only hours after soaring past US$11,000 - a price that represents a gain of more than two-fold since September - bitcoin plunged nearly 20 per cent in less than 90 minutes.

Whether the swoon represented a brief setback or the start of something worse, the wild ride underscored just how volatile the cryptocurrency has become in what some warn could be one of the biggest bubbles of all time.