Technological Change and Demand for Redistribution (submitted)
Latest draft: January 26, 2026
Job Market Paper
Abstract: I study how technological change drives rising income inequality and non-increasing tax progressivity from 1978 to 2018. Linking occupational data with individual survey responses on preferences for income redistribution, I document that workers in computer-intensive occupations support redistribution less, tracking shifts in occupational earnings. Motivated by these findings, I develop and estimate a quantitative model embedding occupational sorting, technological change, and voting over redistribution. I find that rising equipment efficiency, productivity shifts, and composition changes reduce progressivity and increase inequality, while changes in returns to time investment offset these forces. Political feedback further depresses progressivity and amplifies inequality.
Dynamics of U.S. Tax Progressivity: A Quantile Approach (with Wentao Hu, Kun Ho Kim, Wei Biao Wu) (submitted)
Latest draft: June 2, 2025
Abstract: This paper investigates the dynamics of U.S. tax progressivity from 1978 to 2022 by conducting year-by-year quantile regression and simultaneous inference on progressivity estimates. We find that: (i) the least-squares fit of the widely used log-linear tax function capturing the residual income elasticity worsens during recessions, (ii) the U.S. progressivity is counter-cyclical at all income quantiles, with stronger counter-cyclicality at higher income quantiles; (iii) the constancy of the progressivity is rejected in the 1980s with a gradual decline and during recessions with jumps in the progressivity. During recessions, least-squares-implied tax rate is unusually higher than those from the quantile approach.
The Expansion of Social Media Platforms through Intangible Investment (with Xiaohan Zhang) (submitted)
Latest draft: December 24, 2025
Abstract: Social media platforms have expanded rapidly since the early 2000s as households shifted time toward online leisure, despite modest growth in measured labor and physical capital. To understand this gap, we build a multi-sector dynamic general equilibrium model in which platforms use online traffic and invest in intangibles, including leisure-enhancing technologies and data-intensive capital. Calibrating the model to time-use data, firm financial statements, and website traffic, we infer intangible values and productivity paths. From 2003 to 2023, platform growth is driven mainly by intangible accumulation and platform productivity, with intangible investment rising from 0.11% to 3.27% of GDP.
Do ESG Scores Capture Future Climate Damages? A Firm-Level Carbon Burden of Korean Industries (with Yeong Jae Kim, Sehoon Kim, Ju Hyun Pyun, and Moonyoung Kim) (submitted)
Latest draft: February 2, 2026
Abstract: Firms are increasingly engaging in Environmental, Social, and Governance (ESG) activities to pursue decarbonization goals while maintaining profitability. However, there are growing concerns about whether ESG scores accurately reflect firms’ actions toward meaningful reductions in greenhouse gas emissions. Based on Pastor et al. (2024), we develop a framework to quantify the carbon burden at the firm level for major carbon-intensive industries in South Korea to assess whether ESG ratings meaningfully capture corporate actions toward future climate damages. By forecasting future firm-level emissions using a panel VAR model and translating those emissions into monetary values using the EPA's updated Social Cost of Carbon estimates, we show that Korean firms’ ESG scores do not align with their estimated carbon burden. This finding highlights that a substantial share of firms’ external environmental costs remains unincorporated in ESG ratings, an issue that warrants closer attention from ESG rating agencies, investors, and policymakers. We propose that the concept of "carbon burden" can be effectively operationalized into current ESG assessment methodologies. Such a shift would allow evaluators to move beyond historical data and capture the efficacy of a firm's forward-looking climate mitigation strategies.
Political Participation, Intergenerational Transfer, and Capital Accumulation in General Equilibrium
Latest draft: September 15, 2021
Abstract: This paper studies the dynamic politico-economic theory in general equilibrium where repeated voting on an intergenerational tax and transfer system disproportionately aggregates policy preferences of households, and the relative political power depends on households' voting participation, i.e. endogenous turnout. In particular, I incorporate household's turnout decision in an otherwise standard overlapping generations model with capital accumulation. Political process is modeled by the probabilistic voting theory in which the political power emerges endogenously to household's primitives. I characterize the Markov perfect equilibrium and policy rules of the incumbent government and private sector saving. The Social Security tax exhibits a positive relationship with aggregate capital, in contrast to the independent relationship when voter turnout is exogenous. This suggests that agents are faced with a trade-off between political participation and economic welfare, and this trade-off depends on the extent to which the current generation extracts resources from the next unborn generation. The transitional dynamics shows that in response to population aging, capital accumulation and evolution of the endogenous tax rate are substantially different with exogenous and endogenous turnout.
Selected Works in Progress
Skill-promoting Policy and Changes in Technology and Labor Market Power (with Han Gao)
Online Leisure and Digital Platforms in an Open Economy (with Xiaohan Zhang)
Simultaneous Inference of Regression with Time-varying Random Coefficients (with Wentao Hu, Kun Ho Kim, Wei Biao Wu)
Discussion Slides
Discussion Slides for “Perceived versus Calibrated Income Risks in Heterogeneous-agent Consumption Models,” by Tao Wang
Discussion Slides for “Unmasking Social Security: Navigating the Impact on Welfare Distribution,” by Eungsik Kim
Discussion Slides for “Does Protectionism Save Domestic Jobs?: New Evidence from Tariffs on Washing Machines,” by Jaerim Choi