Bubbles for Fama

Robin  Greenwood; Andrei   Shleifer; Yang  You

Article | Journal of Financial Economics | January 2019

Bubbles for Fama

by Robin Greenwood, Andrei Shleifer and Yang You

Abstract

We evaluate Eugene Fama's claim that stock prices do not exhibit price bubbles. Based on U.S. industry returns 1926–2014 and international sector returns 1985–2014, we present four findings: (1) Fama is correct in that a sharp price increase of an industry portfolio does not, on average, predict unusually low returns going forward; (2) such sharp price increases predict a substantially heightened probability of a crash; (3) attributes of the price run-up, including volatility, turnover, issuance, and the price path of the run-up, can all help forecast an eventual crash and future returns; and (4) some of these characteristics can help investors earn superior returns by timing the bubble. Results hold similarly in U.S. and international samples.

Keywords: bubble; market efficiency; predictability; Price Bubble; Stocks; Price; Forecasting and Prediction;

Format: Print

Find at Harvard

Citation:

Greenwood, Robin, Andrei Shleifer, and Yang You. "Bubbles for Fama." Journal of Financial Economics 131, no. 1 (January 2019): 20–43. (Internet Appendix Here.)

McDonald’s reported its fifth consecutive quarter of declining same-store sales growth in early 2015. Despite McDonald’s recent poor performance, Jonathon S. Jacobson, the founder and Chief Investment Officer of Boston-based Highfields Capital Management, had initiated a large position in McDonald’s stock. Jacobson and his team believed that there was enormous upside in McDonald’s stock if management successfully implemented what they perceived to be straightforward operational and financial changes. McDonald’s needed to return to its core competencies of producing quick and reliable burgers and fries. In addition, they believed that financial restructuring could unlock sizable value for investors. Jacobson and his team debated whether to more forcefully articulate their vision for the company and began drafting a letter to Andrew McKenna, McDonald’s Chairman.

We explore the idea that judgment by representativeness reflects the workings of episodic memory, especially interference. In a new laboratory experiment on cued recall, participants are shown two groups of images with different distributions of colors. We find that i) decreasing the frequency of a given color in one group significantly increases the recalled frequency of that color in the other group and ii) for a fixed set of images, different cues for the same objective distribution entail different interference patterns and different probabilistic assessments. Selective retrieval and interference may offer a foundation for the representativeness heuristic, but more generally for understanding the formation of probability judgments from experienced statistical associations.

We develop a model in which risk-averse, specialized bond investors must be paid to absorb shocks to the supply and demand for long-term bonds in two currencies. Since long-term bonds and foreign exchange are both exposed to unexpected movements in short-term interest rates, our model naturally links the predictability of long-term bond returns to the predictability of foreign exchange returns. Specifically, a shift in the net supply of long-term bonds in one currency influences bond term premiums in both currencies as well as the foreign exchange rate between the two currencies. Our model matches several important empirical patterns, including the co-movement between exchange rates and bond term premiums as well as the finding that central banks' quantitative easing policies impact not only local-currency long-term yields, but also foreign exchange rates. We also show that this quantity-driven approach provides a unified account explaining both why foreign exchange tends to outperform when the foreign interest rates exceed domestic rates and why long-term bonds tend to outperform when the yield curve is steep.

Faculty & Research

Bubbles for Fama

Abstract

Citation:

About the Authors

More from these Authors