Large long-run swings in the United States stock market over the past century correspond to swings in estimates of fundamental values calculated by using a long moving average of past dividend growth to forecast future growth rates. Such a procedure would have been reasonable if investors were...

Analyses of the role of rational speculators in financial markets usually presume that such investors dampen price fluctuations by trading against liquidity or noise traders. This conclusion does not necessarily hold when noise traders follow positive-feedback investment strategies buy when...

Recent empirical research has identified a significant amount of volatility in stock prices that cannot be easily explained by changes in fundamentals; one interpretation is that asset prices respond not only to news but also to irrational "noise trading." We assess the welfare effects and...

The claim that financial markets are efficient is backed by an implicit argument that misinformed "noise traders" can have little influence on asset prices in equilibrium. If noise traders' beliefs are sufficiently different from those of rational agents to significantly affect prices, then...