The electronic glitch that cost Knight Capital Group $440m points to a new threat to our digital economy: technological risk.

As one of the largest and most technologically advanced broker-dealers in the US, much of Knight’s trading is handled electronically. Its growth is a reflection of Moore’s law, an observation on the trend towards ever cheaper, faster, and more powerful computer hardware.

However, financial services differs from the semiconductor industry in at least one important respect: human behaviour. As the great physicist Richard Feynman once said: “Imagine how much harder physics would be if electrons had feelings.” While finance undoubtedly benefits from Moore’s law, it must also contend with Murphy’s law: “Whatever can go wrong will go wrong.”