A TheoryofOptimalInheritanceTaxation ∗ ThomasPiketty, Paris School of Economics Emmanuel Saez, UC Berkeley and NBER November 19, 2012 Abstract This paper derives optimal inheritance tax formulas that (a) capture the key equityefficiency trade-off, (b) are expressed in terms of estimable sufficient statistics, (c) are robust to the underlying structure of preferences. We consider dynamic stochastic models with general and heterogeneous bequest tastes and labor productivities. We limit ourselves to simple but realistic linear or two-bracket tax structures to obtain tractable formulas. We show that long-run optimal inheritance tax rates can always be expressed in terms of distributional parameters, aggregate behavioral elasticities and social preferences for redistribution. Importantly, those results carry over with tractable modifications to (a) the case with social discounting (instead of steady-state welfare maximization), (b) the case with partly accidental bequests, (c) the standard Barro-Becker dynastic model. In all cases, the optimal inheritance tax rate increases with the concentration of bequest received and decreases with the elasticity of aggregate bequests to the net-of-tax rate. The optimal tax rate is positive and quantitatively large if concentration is high, the elasticity is low and society cares mostly about those receiving little inheritance. In contrast, the optimal tax rate is negative when society cares mostly about inheritors. We propose a calibration using micro-data for France and the United States. We find that for realistic parameters the optimal inheritance tax rate might be as large as 50%-60% - or even higher for top bequests, in line with historical experience. ∗ ThomasPiketty, Paris School of Economics, firstname.lastname@example.org; Emmanuel Saez, University of California at Berkeley, Department of Economics, email@example.com. We are grateful to seminar participants at the Paris School of Economics, the London School of Economics, the National Bureau of Economic Research (Public Economics Program), the University of California at Berkeley, the Massachusetts Institute of Technology, and Stanford University for their comments. We thank editor Daron Acemoglu, Tony Atkinson, Alan Auerbach, Peter Diamond, Emmanuel Farhi, Mikhail Golosov, Louis Kaplow, Wojciech Kopczuk, Matt Weinzierl, Ivan Werning, and four anonymous referees for very helpful comments and stimulating discussions. We owe special thanks to Bertrand Garbinti for his help with the numerical calibrations. We acknowledge financial support from the Center for Equitable Growth at UC Berkeley. An earlier and longer draft was circulated as “A TheoryofOptimal Capital Taxation,” NBER Working Paper No. 17989, April 2012.