Sebastian Di Tella

Stanford University
Graduate School of Business
655 Knight Way
Stanford, CA 94305
Tel: 650/725-8767

E-Mail: EmailAddress: hidden: you can email any NBER-related person as first underscore last at nber dot org
NBER Program Affiliations: EFG
NBER Affiliation: Faculty Research Fellow
Institutional Affiliation: Stanford University

NBER Working Papers and Publications

January 2020Risk Premium Shocks Can Create Inefficient Recessions
with Robert E. Hall: w26721
We develop an equilibrium theory of business cycles driven by spikes in risk premiums that depress business demand for capital and labor. Aggregate shocks increase firms’ uninsurable idiosyncratic risk and raise risk premiums. We show that risk shocks can create quantitatively realistic recessions, with contractions in employment, consumption, and investment. Business cycles are inefficient—output and employment fall too much during recessions, compared to the constrained-efficient allocation, and consumption should rise. Optimal policy involves stimulating employment and consumption during recessions.
January 2018A Neoclassical Theory of Liquidity Traps
This paper provides an equilibrium theory of liquidity traps and the real effects of money. Money provides a safe store of value that prevents interest rates from falling enough during downturns, and the economy enters a persistent slump with depressed investment. This is an equilibrium outcome—prices are flexible, markets clear, and inflation is on target—but it’s not efficient. Investment is too high during booms and too low during liquidity traps. Although money has large real effects, monetary policy is ineffective—the zero lower bound is not binding, money is superneutral, and Ricardian equivalence holds. The optimal allocation requires the Friedman rule and a tax/subsidy on capital.
November 2017Why are Banks Exposed to Monetary Policy?
with Pablo Kurlat: w24076
We propose a model of banks’ exposure to movements in interest rates and their role in the transmission of monetary shocks. Since bank deposits provide liquidity, higher interest rates allow banks to earn larger spreads on deposits. Therefore, if risk aversion is higher than one, banks' optimal dynamic hedging strategy is to take losses when interest rates rise. This risk exposure can be achieved by a traditional maturity-mismatched balance sheet, and amplifies the effects of monetary shocks on the cost of liquidity. The model can match the level, time pattern, and cross-sectional pattern of banks’ maturity mismatch.
July 2017Optimal Regulation of Financial Intermediaries
I characterize the optimal financial regulation policy in an economy where financial intermediaries trade capital assets on behalf of households, but must retain an equity stake to align incentives. Financial regulation is necessary because intermediaries cannot be excluded from privately trading in capital markets. They don’t internalize that high asset prices force everyone to bear more risk. The socially optimal allocation can be implemented with a tax on asset holdings. I derive a sufficient statistic for the externality/optimal policy in terms of observable variables, valid for heterogenous intermediaries and asset classes, and arbitrary aggregate shocks. I use market data on leverage and volatility of intermediaries’ equity to measure the externality, which co-moves with the business...

Published: Sebastian Di Tella, 2019. "Optimal Regulation of Financial Intermediaries," American Economic Review, vol 109(1), pages 271-313.

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