That a heavyweight like Cargill Dow is convinced it can beat conventional plastics on cost and performance alone may be the best reason to think that biopolymers are about to burst out of their mouldy, green niche.

ECONOMIST: Evanescent or evergreen?

Then fill in the allocation with low cost funds since low cost has been one of the best indicators of superior future performance.

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In an influential 1993 paper Narasimhan Jegadeesh, now a professor at Emory University, showed that a so-called zero cost strategy of buying stocks with the best six-month performance and shorting stocks with the worst six-month performance returned 12% a year.

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