Optimal Regulation of Financial Intermediaries
研究了金融中介因私下交易资产而产生外部性时，如何通过资产持有税实现社会最优配置，并利用杠杆和股权波动数据测度外部性。
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 and use market data on leverage and volatility of intermediaries’ equity to measure it.