Demographics, Wealth, and Global Imbalances in the Twenty-First Century § Adrien Auclert∗ Hannes Malmbergy Frédéric Martenetz Matthew Rognlie August 2021 Abstract We use a sufficient statistic approach to quantify the general equilibrium effects of population aging on wealth accumulation, expected asset returns, and global im- balances. Combining population forecasts with household survey data from 25 coun- tries, we measure the compositional effect of aging: how a changing age distribution affects wealth-to-GDP, holding the age profiles of assets and labor income fixed. In a baseline overlapping generations model this statistic, in conjunction with cross- sectional information and two standard macro parameters, pins down general equi- librium outcomes. Since the compositional effect is positive, large, and heterogeneous across countries, our model predicts that population aging will increase wealth-to- GDP ratios, lower asset returns, and widen global imbalances through the twenty-first century. These conclusions extend to a richer model in which bequests, individual savings, and the tax-and-transfer system all respond to demographic change. ∗Stanford University, NBER and CEPR. Email:
[email protected]. yUniversity of Minnesota. Email:
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[email protected]. §Northwestern University and NBER. Email:
[email protected]. For helpful comments, we thank Rishabh Aggarwal, Mark Aguiar, Anmol Bhandari, Olivier Blanchard, Maricristina De Nardi, Charles Goodhart, Nezih Guner, Fatih Guvenen, Daniel Harenberg, Martin Holm, Gregor Jarosch, Patrick Kehoe, Patrick Kiernan, Pete Klenow, Dirk Krueger, Kieran Larkin, Ellen McGrat- tan, Kurt Mitman, Ben Moll, Serdar Ozkan, Christina Patterson, Alessandra Peter, Jim Poterba, Jacob Rob- bins, Richard Rogerson, Ananth Seshadri, Isaac Sorkin, Kjetil Storesletten, Ludwig Straub, Amir Sufi, Chris Tonetti, David Weil, Arlene Wong, Owen Zidar and Nathan Zorzi.