Portraits of US trio Eugene F Fama, Lars Peter Hansen and Robert J Shiller, who won jointly the Nobel Prize in Economic Sciences 2013, is seen on a computer screen at the Royal Swedish Academy of Sciences, in Stockholm, on October 14, 2013. - 

The Nobel Committee has awarded the Nobel Prize in economics to three Americans: Eugene Fama, Lars Peter Hansen, and Robert Shiller. The trio has focused on the behavior of the stock market as well as the efficiency of markets. Marketplace’s Nancy Marshall Genzer joins David Brancaccio to discuss the economists and their work.