'Sell in May and go away’ is the oldest stock market adage. As the recovery stutters, it seems true. A study by Professor Ben Jacobsen and Sven Bouman of Aegon Asset Management in The Hague concluded: "Surprisingly, we found this inherited wisdom of sell in May to be true in 36 of 37 developed and emerging markets. Evidence shows that in Britain the seasonal effect has been noticeable since 1694."