IN MOST businesses, a small coding error is a minor problem. With Bitcoin, an online “cryptocurrency”, a fairly simple flaw seems to have cost $5.3 billion. That is how much the value of all of the Bitcoin in the world has fallen over the past two weeks, after a bug caused several Bitcoin exchanges to halt withdrawals temporarily. The price of a Bitcoin, which peaked at about $1,200 in December, is now about $630 on Bitstamp, one of the exchanges that has resumed trading. On Mt Gox, another exchange based in Tokyo, coins that still cannot be withdrawn are selling for far less (see chart).
