PhD Candidate in Economics, New York University
ame384@nyu.edu or msebsim@gmail.com
Research Interests: Macroeconomics, Finance, Firm Dynamics
References: Virgiliu Midrigan, Corina Boar, Mark Gertler, Diego Perez
I am on the 2026–27 economics job market.
Scope Economies and Allocative Efficiency, November 2026 PDF
Abstract: Size-dependent distortions misallocate resources, yet in standard models they account for only a small share of cross-country income gaps. These models abstract from firm scope and organization. When firms share management across products, they benefit from scope economies, and revenue per product rises with the number of products. Using product-level data, I find this relationship in the US but not in India, suggesting that firms in the two countries organize production differently. I rationalize this pattern in a model where firms choose their scope and whether to adopt costly non-rival management. Adoption raises productivity, and more so for large firms. I introduce distortions to match the Indian firm-size distribution and show that they deter adoption, rationalizing the absence of scope economies in India. The effects of these distortions are amplified by large firms forgoing non-rival management. With scope economies, distortions can account for 80% of the gap in GDP per worker between the US and India, compared with 20% without.
An Odd Approximation of Inflation for State-dependent Pricing Models, November 2026 PDF
Abstract: We derive a tractable state-space representation of state-dependent pricing models that tracks only three moments of the price-gap distribution while preserving frequency and selection effects. The model can be estimated with standard DSGE tools. Applied to the 2021–22 inflation surge, it shows that much of what linear models attribute to cost-push shocks is endogenous amplification.
Sophisticated Borrowing Constraints and Macroeconomic Dynamics, May 2026 PDF
with Chen Lian, Yueran Ma, Pablo Ottonello and Diego Perez
Revise and Resubmit American Economic Review
Abstract: Standard macro-finance models feature hard borrowing constraints that force indiscriminate deleveraging after adverse shocks, producing financial acceleration. We instead model earnings-based covenants as debt thresholds whose violation transfers control rights to creditors, who then maximize their value rather than cut credit mechanically. The model matches micro evidence around covenant violations and generates no financial acceleration.
When Liquidity Matters: Firm Balance Sheets During Large Crises, March 2026 PDF
with Miguel Faria-e-Castro and Julian Kozlowski
Conditionally Accepted JPE Macro
Abstract: During both the GFC and COVID-19, credit spreads spiked and investment fell, but firm debt and liquidity fell in the former and rose in the latter. Leverage drove the GFC cross-section; liquidity drove COVID-19's. A calibrated macro-finance model with a working-capital liquidity motive attributes the GFC to real and financial shocks, and COVID-19 partly to liquidity shocks.
Implications of Market Power for Financial Frictions, March 2026 PDF
Abstract: In a macro-finance model with variable markups and earnings-based borrowing constraints, eliminating markups depresses profits, tightens constraints, and worsens capital misallocation. This interaction explains 25 percent of misallocation, costing 2.1 percent of aggregate productivity. A constrained planner optimally tolerates markup dispersion, letting markups approach competitive levels for firms with higher financing costs.
Precautionary Pricing, October 2025 PDF
Abstract: Firms set prices and inventories before demand is realized. In a model with risk-averse firms facing idiosyncratic demand uncertainty, precautionary behavior generates markup dispersion even under constant demand elasticity, matching U.S. evidence on volatility, inventories, and markups. During supply-chain disruptions, heightened stock-out risk raises aggregate markups and delays recovery, amplifying aggregate fluctuations.
The Local-Spillover Decomposition of an Aggregate Causal Effect, April 2026 PDF
with Tim Conley, Bill Dupor, Jingchao Li, and Peter McCrory
Federal Reserve Bank of St. Louis Review
Abstract: This article presents a method to decompose the causal effects of U.S. defense spending on income into a local effect and a spillover effect using panel data. We estimate positive local and spillover multipliers. By construction, the sum provides an estimate of the aggregate multiplier, which is slightly greater than one in our benchmark specification. Using disaggregate data improves precision relative to using aggregate data alone. More generally, we provide a template to conduct inference on local, spillover, and aggregate causal effects in a unified framework