Speculating on Higher Order Beliefs

Higher order beliefs - beliefs about others' beliefs - may be important for trading behavior and asset prices, but have received little systematic empirical examination due to challenges in measurement. We study more than twenty years of evidence from the Robert Shiller Investor Confidence surveys, which directly elicit details on individual and institutional investors' higher order beliefs about the U.S. stock market. We find that investors' higher order beliefs provide substantial motivations for non-fundamental speculation, e.g., to buy into a stock market perceived to be overvalued. Guided by the evidence, we construct a theoretical model that reveals that higher order beliefs may substantially amplify stock market fluctuations. When investors exhibit the same fundamental belief biases that they attribute to other investors, phenomena such as overreaction, momentum, and reversal can persist in equilibrium even though everybody knows about them