MARKETS frequently froth and bubble, but the boom in bitcoin, a digital currency, is extraordinary. Although its price is down from an all-time high of $2,420 on May 24th, it has more than doubled in just two months. Anyone clever or lucky enough to have bought $1,000 of bitcoins in July 2010, when the price stood at $0.05, would now have a stash worth $46m. Other cryptocurrencies have soared, too, giving them a collective market value of about $80bn.
Ascents this steep are rarely sustainable. More often than not, the word “bitcoin” now comes attached to the word “bubble”. But the question of what has driven up the price is important. Is this just a speculative mania, or is it evidence that bitcoin is taking on a more substantial role as a medium of exchange or a store of value? Put another way, is bitcoin like a tulip, gold or the dollar—or is it something else entirely?