We study optimal monetary and fiscal policies in a New Keynesian model with heterogeneous agents, incomplete markets, and nominal rigidities. Our approach uses small‐noise expansions and Fréchet derivatives to approximate equilibria quickly and efficiently. Responses of optimal policies to...

We develop a unified framework for optimally managing public portfolios for a class of macro-finance models that include widely-used specifications for households' risk and liquidity preferences, market structures for financial assets, and trading frictions. An optimal portfolio hedges...

We develop a perturbational technique to approximate equilibria of a wide class of discrete-time dynamic stochastic general equilibrium heterogeneous-agent models with complex state spaces, including multi-dimensional distributions of endogenous variables. We show that approximating policy...