The market collapse is prompting institutional investors to rethink the way they build their portfolios. Nathan Fischer, chief investment officer at Lumina Foundation, has one solution.

He eschews both rigid asset allocation targets and traditional benchmarks - aspects of typical portfolios that prevent investors taking advantage of market dislocations and force them to make difficult rebalancing decisions. Instead, Mr Fischer organises the Indianapolis-based foundation's $1.2bn (£782m, €932m) portfolio by reference to just four broad categories.