The collapse of Lehman Brothers in September 2008 caught markets and regulators by surprise. Although the government rushed to rescue other financial institutions from a similar fate after Lehman, it could not prevent the deepest recession in postwar history. A Crisis of Beliefs makes us rethink the financial crisis and the nature of economic risk. In this authoritative and comprehensive book, two of today’s most insightful economists reveal how our beliefs shape financial markets, lead to expansions of credit and leverage, and expose the economy to major risks. Nicola Gennaioli and Andrei Shleifer carefully walk readers through the unraveling of Lehman Brothers and the ensuing meltdown of the U.S. financial system and then present new evidence to illustrate the destabilizing role played by the beliefs of home buyers, investors, and regulators. Using the latest research in psychology and behavioral economics, they present a new theory of belief formation that explains why the financial crisis came as such a shock to so many people—and how financial and economic instability persist. A must-read for anyone seeking insights into financial markets, A Crisis of Beliefs shows how even the smartest market participants and regulators did not fully appreciate the extent of economic risk and offers a new framework for understanding today’s unpredictable financial waters.
Pedro Bordalo, Katherine Baldiga Coffman, Nicola Gennaioli and Andrei Shleifer
We conduct laboratory experiments that explore how gender stereotypes shape beliefs about ability of oneself and others in different categories of knowledge. The data reveal two patterns. First, men’s and women’s beliefs about both oneself and others exceed observed ability on average, particularly in difficult tasks. Second, overestimation of ability by both men and women varies across categories. To understand these patterns, we develop a model that separates gender stereotypes from misestimation of ability related to the difficulty of the task. We find that stereotypes contribute to gender gaps in self-confidence, assessments of others, and behavior in a cooperative game.
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.
Greenwood, Robin, Andrei Shleifer, and Yang You. "Bubbles for Fama."Journal of Financial Economics 131, no. 1 (January 2019): 20–43. (Internet Appendix Here.)
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Nicholas Barberis, Robin Greenwood, Lawrence Jin and Andrei Shleifer
We present an extrapolative model of bubbles. In the model, many investors form their demand for a risky asset by weighing two signals: an average of the asset’s past price changes and the asset’s degree of overvaluation. The two signals are in conflict, and investors “waver” over time in the relative weight they put on them. The model predicts that good news about fundamentals can trigger large price bubbles. We analyze the patterns of cash-flow news that generate the largest bubbles, the reasons why bubbles collapse, and the frequency with which they occur. The model also predicts that bubbles will be accompanied by high trading volume and that volume increases with past asset returns. We present empirical evidence that bears on some of the model’s distinctive predictions.
Barberis, Nicholas, Robin Greenwood, Lawrence Jin, and Andrei Shleifer. "Extrapolation and Bubbles."Journal of Financial Economics 129, no. 2 (August 2018): 203–227.
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Robin Greenwood, Samuel G. Hanson, Andrei Shleifer and Jakob Ahm Sørensen
Using historical data on post-war financial crises around the world, we show that crises are
substantially predictable. The combination of rapid credit and asset price growth over the prior
three years, whether in the nonfinancial business or the household sector, is associated with about
a 40% probability of entering a financial crisis within the next three years. This compares with a
roughly 7% probability in normal times, when neither credit nor asset price growth has been
elevated. Our evidence cuts against the view that financial crises are unpredictable “bolts from the
sky” and points toward the Kindleberger-Minsky view that crises are the byproduct of predictable,
boom-bust credit cycles. The predictability we document favors macro-financial policies that “lean
against the wind” of credit market booms.
Greenwood, Robin, Samuel G. Hanson, Andrei Shleifer, and Jakob Ahm Sørensen. "Predictable Financial Crises." Harvard Business School Working Paper, No. 20-130, June 2020.
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Pedro Bordalo, Katherine Baldiga Coffman, Nicola Gennaioli, Frederik Schwerter and Andrei Shleifer
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.
Bordalo, Pedro, Katherine Baldiga Coffman, Nicola Gennaioli, Frederik Schwerter, and Andrei Shleifer. "Memory and Representativeness." NBER Working Paper Series, No. 25692, March 2019. (Revised January 2020.)
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Pedro Bordalo, Nicola Gennaioli, Spencer Yongwook Kwon and Andrei Shleifer
We introduce diagnostic expectations into a standard setting of price formation in which investors learn about the fundamental value of an asset and trade it. We study the interaction of diagnostic expectations with two well-known mechanisms: learning from prices and speculation (buying for resale). With diagnostic (but not with rational) expectations, these mechanisms lead to price paths exhibiting three phases: initial underreaction, followed by overshooting (the bubble), and finally a crash. With learning from prices, the model generates price extrapolation as a byproduct of fast moving beliefs about fundamentals, which lasts only as the bubble builds up. When investors speculate, even mild diagnostic distortions generate substantial bubbles.
Bordalo, Pedro, Nicola Gennaioli, Spencer Yongwook Kwon, and Andrei Shleifer. "Diagnostic Bubbles." NBER Working Paper Series, No. 25399, December 2018.
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