A model in which homebuyers make a modest approximation leads house prices to display three features present in the data but usually missing from rational models: momentum at one-year horizons, mean reversion at five-year horizons, and excess longer-term volatility relative to fundamentals. Approximating buyers assume that past prices reflect only contemporaneous demand, just like professional economists who use trends in housing prices to infer trends in housing demand. Consistent with survey evidence, this approximation leads buyers to expect increases in the market value of their homes after recent house price increases.

ABSTRACT This paper studies the role of disagreement in amplifying housing cycles. Speculation is easier in the land market than in the housing market due to frictions that make renting less efficient than owner‐occupancy. As a result, undeveloped land facilitates construction and intensifies the speculation that causes booms and busts in house prices. This observation challenges the standard intuition that in cities where construction is easier, house price booms are smaller. It can also explain why the largest house price booms in the United States between 2000 and 2006 occurred in areas with elastic housing supply.

Using data on 50 million home sales from the last U.S. housing cycle, we document that much of the variation in volume came from the rise and fall in speculation. Cities with larger speculative booms have larger price booms, sharper increases in unsold listings as the market turns, and more severe busts. We present a model in which predictable price increases endogenously attract short-term buyers more than long-term buyers. Short-term buyers amplify volume by selling faster and destabilize prices through positive feedback. Our model matches key aggregate patterns, including the lead–lag price–volume relation and a sharp rise in inventories.

We study the effects of policies proposed to address “short-termism” in financial markets. We examine a noisy rational expectations model in which investors’ exposures and information about fundamentals endogenously vary across horizons. In this environment, taxing or outlawing short-term investment doesn’t negatively affect the information in prices about long-term fundamentals. However, such a policy reduces short- and long-term investors’ profits and utility. Changing policies about the release of short-term information can help long-term investors—an objective of some policy makers—at the expense of short-term investors. Doing so also makes prices less informative and increases costs of speculation. Received June 24, 2018; editorial decision February 19, 2019 by Editor Stijn Van Nieuwerburgh. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.

Taxation affects the allocation of talented individuals across professions by blunting material incentives and thus magnifying nonpecuniary incentives of pursuing a “calling.” Estimates from the literature suggest that high-paying professions have negative externalities, whereas low-paying professions have positive externalities. A calibrated model therefore prescribes negative marginal tax rates on middle-class incomes and positive rates on the rich. The welfare gains from implementing such a policy are small and are dwarfed by the gains from profession-specific taxes and subsidies. These results depend crucially on externality estimates and labor substitution patterns across professions, both of which are very uncertain given existing empirical evidence.