This paper studies asset pricing and labor market dynamics when idiosyncratic risk to human capital is not fully insurable. Firms use long‐term contracts to provide insurance to workers, but neither side can fully commit; furthermore, owing to costly and unobservable retention effort, worker‐firm relationships have endogenous durations. Uninsured tail risk in labor earnings arises as a part of an optimal risk‐sharing scheme. In equilibrium, exposure to the tail risk generates higher aggregate risk premia and higher return volatility. Consistent with data, firm‐level labor share predicts both future returns and pass‐throughs of firm‐level shocks to labor compensation.

We develop a theory of sweat equity—the value of business owners’ time and expenses to build customer bases, client lists, and other intangible assets. We discipline the theory using data from U.S. national accounts, business censuses, and brokered sales to estimate a value for sweat equity in the private business sector equal to 1.2 times U.S. GDP, which is about the same magnitude as the value of fixed assets in use in these businesses. For a typical owner, 26% of the sweat equity is transferable through inheritance or sale. The equity values are positively correlated with business incomes and standard measures of markups based on accounting data, but not with owners’ financial assets or standard measures of business total factor productivity. We use our theory to show that abstracting from sweat activity leads to a significant understatement of the effects of lowering business income tax rates on private business activity for both the extensive and intensive margins. Despite finding larger responses, our model’s implied tax elasticities of establishments and owner hours are in line with empirical estimates in the public finance literature. Allowing for financial constraints and superstar firms does not overturn our main findings.

This paper develops a theory of subjective beliefs that departs from rational expectations, and shows that biases in household beliefs have quantitatively large effects on macroeconomic aggregates. The departures are formalized using model-consistent notions of pessimism and optimism which are supported by extensive time-series and cross-sectional evidence from household surveys. The role subjective beliefs play in aggregate fluctuations is quantified in a business cycle model with goods and labour market frictions. Consistent with the survey evidence, an increase in pessimism generates upward biases in unemployment and inflation forecasts and lowers economic activity. The underlying belief distortions reduce aggregate demand and propagate through frictional goods and labour markets. As a by-product of the analysis, solution techniques that preserve the effects of time-varying belief distortions in the class of linear solutions are developed.

This paper examines the nature of entrepreneurship using a novel panel dataset based on US Internal Revenue Service data. We analyze income growth trajectories and the determinants of entrepreneurial choice for business owners. Compared with prior household survey–based studies, we find that self-employed individuals have significantly higher average incomes and steeper income growth than their wage-earning matched peers. Contrary to survey evidence, we find a limited role for nonpecuniary motives, uninsurable risk, and liquidity constraints driving entrepreneurial choice. Prior work experience predicts entrepreneurial entry. Entry and exit rates into self-employment remain stable over time, including during the Great Recession.

A Ramsey planner chooses a distorting tax on labor and manages a portfolio of securities in an economy with incomplete markets. We develop a method that uses second order approximations of Ramsey policies to obtain formulas for conditional and unconditional moments of government debt and taxes that include means and variances of the invariant distribution as well as speeds of mean reversion. The asymptotic mean of the planner's portfolio minimizes a measure of fiscal risk. We obtain analytic expressions that approximate moments of the invariant distribution and apply them to data on a primary government deficit, aggregate consumption, and returns on traded securities. For U.S. data, we find that the optimal target debt level is negative but close to zero, the invariant distribution of debt is very dispersed, and mean reversion is slow.

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 aggregate shocks differ qualitatively from what they would be in a corresponding representative agent economy and are an order of magnitude larger. A motive to provide insurance that arises from heterogeneity and incomplete markets outweighs price stabilization motives.

We study optimal public portfolios in a class of macro-finance models that includes widely used specifications of households’ risk and liquidity preferences, market structures for financial assets, and trading frictions. An optimal portfolio hedges fluctuations in interest rates, primary surpluses, and income inequalities. We express an optimal portfolio in terms of statistics that are functions only of macro and financial market data. An application to US data shows that hedging interest rate risk plays a dominant role in shaping an optimal maturity structure of US government debt.