The past forty years have seen a rapid rise in top income inequality in the United States. While there is a large number of existing theories of the Pareto tails of the income and wealth distributions at a given point in time, almost none of these address the fast rise in top inequality observed...

We recast the Aiyagari-Bewley-Huggett model of income and wealth distribution in continuous time. This workhorse model - as well as heterogeneous agent models more generally - then boils down to a system of partial differential equations, a fact we take advantage of to make two types of...

We define risk transfer as the percent change in the market risk exposure for a group of investors over a given period. We estimate risk transfer using novel data on U.S. investors' portfolio holdings, flows, and returns at the security level with comprehensive coverage across asset classes and...

We develop a framework to theoretically and empirically analyze the fluctuations of the aggregate stock market. Households allocate capital to institutions, which are fairly constrained, for example operating with a mandate to maintain a fixed equity share or with moderate scope for variation in...

We propose a new way to construct instruments in a broad class of economic environments: "granular instrumental variables" (GIVs). In the economies we study, a few large firms, in- dustries or countries account for an important share of economic activity. As the idiosyncratic shocks from these...

We use novel monthly security-level data on U.S. household portfolio holdings, flows, and returns to analyze asset demand across an extensive range of asset classes, including both public and private assets. Our dataset covers a broad range of households across the wealth distribution, notably...

We propose a theory of the complexity of economic decisions. Leveraging a macroeconomic framework of production functions, we conceptualize the mind as a cognitive economy, where a task's complexity is determined by its composition of cognitive operations. Complexity emerges as the inverse of...

Firm characteristics, based on accounting and financial market data, are commonly used to represent firms in economics and finance. However, investors collectively use a much richer information set beyond firm characteristics, including sources of information that are not readily available to...

We provide a quantitative analysis of the trade-offs between health outcomes and the distribution of economic outcomes associated with alternative policy responses to the COVID-19 pandemic. We integrate an expanded SIR model of virus spread into a macroeconomic model with realistic income and...

How much does life-cycle human capital accumulation vary across countries? This paper seeks to answer this question by studying U.S. immigrants, who come from a wide variety of countries but work in a common labor market. We document that returns to potential experience among U.S. immigrants are...