What is the most challenging task for analysts in modern investment markets? Aside from justifying the pay of investment bankers, a plausible candidate would surely be the difficulty of identifying in advance the emerging secular trends that will prove to be the most important influences on returns over subsequent periods of 10-20 years.

This simple sounding objective in practice is something that the professional investment community finds surprisingly hard to pull off, as Jim Grant, the noted New York bond market watcher, noted in a recent speech. Like me, Mr Grant is just about old enough to recall the historic nadir of bond prices in 1981.