As Christmas approaches, leading stock indices continue to soar higher than the festive reindeer. The Dow Jones industrial Average is now 70% above its pre-crisis peak, with this year’s gain the highest since the financial crisis. Equity returns in advanced economies have been driven by an economic recovery, which boosted corporate profits, and an historic expansion in central bank balance sheets, which lowered discount rates and channelled funds into equity markets through portfolio rebalancing effects. The music must stop at some point, though…