What are hedge funds, and how did they (accidentally) send GameStop’s stock flying ‘to the moon’?

An unusual battle has been playing out between anti-establishment Reddit nerds and Wall Street’s corporate titans over the past week.

Caught in the middle is a struggling video game chain called GameStop, which you wouldn’t suspect to be in any trouble if all you looked at was its share price.

It surged from about $US19 to $US483 (at its peak) in just three weeks — a gain of more than 2,400 per cent.

Not bad for an old-fashioned retailer (which has been dubbed the “Blockbuster Video” of the gaming industry) as consumers are increasingly abandoning physical stores, and downloading their games online.

Despite its doomed business model, users of a Reddit group called “WallStreetBets” (which has over 5.7 million members) have been…