High-skilled workers and high-productivity firms co-locate in large cities. In this paper, I study how the two-sided sorting of workers and firms affects spatial earnings inequality, efficiency of the allocation of workers and firms across cities, and the welfare consequences of place-based policies. I build a general equilibrium model in which heterogeneous workers and firms sort across cities and match within cities. I structurally estimate the model using Canadian matched employer-employee data and decompose the urban earnings premium, finding that worker and firm sorting account for 67% and 27% of this premium, respectively. The decentralized equilibrium is inefficient as low-productivity firms overvalue locating in high-skilled cities. The optimal spatial policy would incentivize high-skilled workers and high-productivity firms to co-locate to a greater extent while redistributing income towards low-earning cities, leading to a 6% increase in social welfare. Model counterfactuals underscore the importance of two-sided sorting when evaluating distributional and aggregate outcomes of place-based policies.

We analyze the cross-country spillover effects of corporate tax reforms. Combining firm-level evidence on the 2017 U.S. Tax Cuts and Jobs Act (TCJA) with a quantitative general-equilibrium model, we show how multinational enterprises (MNEs) propagate local policy shocks throughout the global economy. Our framework emphasizes three properties of intangible capital: non-rivalry, mobile ownership, and technology spillovers. We find the TCJA generated positive outward spillovers: First, it boosted U.S. MNEs' intangible investment, raising their foreign subsidiaries' output. Second, it increased tangible investment of foreign MNEs' U.S. subsidiaries, incentivizing them to expand intangible investment at home. Conversely, a Global Minimum Tax (GMT) in the rest of the world generates negative inward spillovers for the United States. It raises the effective tax rate on U.S. MNEs' foreign income, depressing their intangible investment, while simultaneously reducing foreign MNEs' intangible investment and thus their U.S. subsidiaries' output. These findings illustrate the complex trade-offs between tax-base protection and real economic activity in an interconnected policy environment.

Redevelopment is a major source of housing supply in dense cities, but it is spatially concentrated and often associated with gentrification and displacement. This paper studies the equilibrium consequences of redevelopment and of policies that restrict it. We first empirically evaluate a teardown tax implemented in two Chicago neighborhoods using a spatial difference-in-differences design and find that it substantially reduced demolitions and modestly curbed displacement. We then develop a dynamic general equilibrium model with forward-looking landlords who choose when to redevelop and heterogeneous households who choose across neighborhoods and vertically differentiated housing units. Redevelopment affects income sorting across neighborhoods and generates filtering dynamics over time. Model counterfactuals show that a spatially targeted teardown tax preserves old, affordable housing in treated areas but shifts redevelopment to untreated areas, raising rents there. The policy benefits low-income households but harms middle- and high-income households, with the largest losses for the middle. Land values fall in treated areas and rise elsewhere. We conclude with a discussion of the policy implications of our findings.

Are larger firms more productive, more scalable, or both? We use firm-level panel data from thirteen countries and employ a broad set of methods to estimate factor elasticities--capturing returns to scale (RTS)--and total factor productivity (TFP). We find substantial RTS heterogeneity within industries, with larger firms exhibiting higher RTS driven by greater intermediate input elasticities. TFP, by contrast, rises with firm size only up to the top decile before declining. Incorporating RTS heterogeneity into a standard model of entrepreneurship more than doubles the efficiency losses from financial frictions compared with a conventional calibration with only TFP differences.

It has been documented that larger cities foster faster earnings growth, which is an important driver for cross-sectional spatial earnings inequality. In this paper, I empirically investigate the sources of the urban earnings growth premium. I find that the between-firm and within-firm growth components each explain 66% and 34% of the greater returns to big city experience, respectively. Workers do not move between jobs more frequently but enjoy a steeper job ladder in larger cities. Faster within-firm learning in larger cities is mostly explained by better learning environments at the firm level. The empirical results highlight the important role of firm heterogeneity across cities in explaining the dynamic gains from working in bigger cities.