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Shiller: 1928? 1987? What history tells us about market optimism

The general mood in markets has been optimistic, but at the World Economic Forum, experts are debating how long the rally will last.

Yahoo Finance's Jen Rogers caught up with Nobel prize winning economist, Robert Shiller — who predicted the last housing and tech bubbles in his book “Irrational Exuberance.” She asked him what he thinks about the mood and the ever-moving-higher markets.