Few understand the ways of the herd better than Robert Arnott, founder of index provider Research Affiliates of California. A 1977 triple major in economics, applied mathematics and computer science at the University of California, he developed skills in tactical asset allocation that helped him to build not one, but two, asset management firms.

His first, TSA Capital Management, oversaw $3 billion when he left in 1987. His second, First Quadrant, ran $18 billion by 2002.