Investment theory, Macquarie strategist Viktor Shvets argues, is predicated on predictability, rationality and what he calls “estimable uncertainties”. For example, we may not know what the Federal Reserve or the Reserve Bank is going to do next, but markets can make educated guesses within a fairly narrow range.

For investors, policy changes are manageable. But historic, unpredictable changes in policy regimes are much harder to navigate. There is simply no easy playbook.