Rob Arnott, founder and chairman of asset manager Research Affiliates in Newport Beach, California, is one of the big thinkers in finance today.

A former editor of the prestigious Financial Analysts Journal, Arnott, 54, has developed expertise in asset allocation, indexing, and pension funds, among other topics. He's a fierce proponent of fundamental indexing - in which metrics such as aggregate sales and cash flow are used to weight companies in an index, as opposed to market capitalisation.