Burton G. Malkiel, the economist known for being one of the biggest proponents of index investing, continues to be among the skeptics of smart-beta mutual funds and exchange-traded funds. "In that [smart beta] does enhance returns, it’s likely because the portfolios have additional risk," Malkiel said in an interview. "It isn’t some smart new way to outperform on a risk-adjusted basis." Read the original story from MarketWatch.