The conventional wisdom of academic investment theorists is taking a terrible beating in the post-bubble era. Rightly so, in the case of the efficient market theory, which now gives rise to growing scepticism.

The notion that stocks follow a random walk and all available information is in the price has always looked suspect in the light of history, which repeatedly tells us that Homo economicus is not the rational man of the economists’ musings and that markets are prone to periodic bubbles. In its strongest form it even attributes the success of investors such as Warren Buffett and Fidelity’s Anthony Bolton to pure luck, which to my mind is too strong by half.