Residential property-to-let, private loans and clean energy are among the esoteric asset classes being put forward to pension schemes by leading investment consultants, as liquidity pushes bonds and equities to stratospherically high levels.

To combat the wave of liquidity originating from central banks' quantitative-easing policies, which is pushing up prices, investors should "embrace a broader perspective on risk management in order to meet their objectives", according to Mercer's Themes and Opportunities report published Tuesday.