Beating the market four or five years in a row may seem like a conclusive demonstration of investment skill, but it may well be all down to luck. Photograph: Spencer Platt/Getty Images

Consider the following situation. You receive an email from a fund manager boasting of his uncannily accurate stock-picking system, one that he promis(...)

Mark Karpeles (left), chief executive officer of Mt Gox, leaves the Tokyo District Court yesterday. Photograph: Tomohiro Ohsumi/Bloomberg

Bitcoin’s faltering reputation as a viable currency has been dealt a severe blow, with its biggest exchange filing for bankruptcy in the wake o(...)