In Search of the Origins of Financial Fluctuations: The Inelastic Markets Hypothesis

106 Pages Posted: 23 Oct 2020

See all articles by Xavier Gabaix

Xavier Gabaix

Harvard University - Department of Economics; National Bureau of Economic Research (NBER); Centre for Economic Policy Research (CEPR); European Corporate Governance Institute (ECGI)

Ralph S. J. Koijen

University of Chicago - Booth School of Business; Centre for Economic Policy Research (CEPR); National Bureau of Economic Research (NBER)

Date Written: October 22, 2020

Abstract

We develop a framework to theoretically and empirically analyze the fluctuations of the aggregate stock market. Households allocate capital to institutions, which are fairly constrained, for example operating with a mandate to maintain a fixed equity share or with moderate scope for variation. As a result, the price elasticity of demand of the aggregate stock market is small, so flows in and out of the stock market have large impacts on prices.

Using the recent method of granular instrumental variables, we find that investing $1 in the stock market increases the market’s aggregate value by about $5. We also show that we can trace back the time variation in the market’s volatility to flows and demand shocks of different investors. We also analyze how key parts of macro-finance change if markets are inelastic. We show how pricing kernels and general equilibrium models can be generalized to incorporate flows, which makes them amenable to use in more realistic macroeconomic models, and to policy analysis. Our calibration implies that government purchases of equities have a non-trivial impact on prices. Corporate actions that would be neutral in a rational model, such as share buybacks, have substantial impacts too.

Our framework allows us to give a dynamic economic structure to old and recent datasets comprising holdings and flows in various segments of the market. The mystery of apparently random movements of the stock market, hard to link to fundamentals, is replaced by the more manageable problem of understanding the determinants of flows in inelastic markets. We delineate a research agenda that can explore a number of questions raised by this analysis, and might lead to a more concrete understanding of the origins of financial fluctuations across markets.

Suggested Citation

Gabaix, Xavier and Koijen, Ralph S. J., In Search of the Origins of Financial Fluctuations: The Inelastic Markets Hypothesis (October 22, 2020). Available at SSRN: https://ssrn.com/abstract=3686935 or http://dx.doi.org/10.2139/ssrn.3686935

Xavier Gabaix

Harvard University - Department of Economics ( email )

Littauer Center
Cambridge, MA 02138
United States

National Bureau of Economic Research (NBER)

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

Centre for Economic Policy Research (CEPR)

London
United Kingdom

European Corporate Governance Institute (ECGI)

c/o the Royal Academies of Belgium
Rue Ducale 1 Hertogsstraat
1000 Brussels
Belgium

Ralph S. J. Koijen (Contact Author)

University of Chicago - Booth School of Business ( email )

5807 S. Woodlawn Avenue
Chicago, IL 60637
United States

HOME PAGE: http://faculty.chicagobooth.edu/ralph.koijen/

Centre for Economic Policy Research (CEPR) ( email )

London
United Kingdom

National Bureau of Economic Research (NBER) ( email )

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

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