Publications

A Practitioner’s Guide to Using Data on Private Equity Hospital Acquisitions [Paper] [Data] (with Mark Naslund, Sally Wang, Abid Hasan, Elijah Huang, Hyong-gu Hwang, Ambar La Forgia, Ryan McDevitt, Riley League, and Kelly Kaili Yang)

Selected Presentations: Annual Conference of the American Society of Health Economists 2026

Featured: Editor’s Choice article, Health Affairs Scholar

Abstract: Private equity (PE) investment in U.S. hospitals has drawn increasing policy and research attention, but empirical analysis has been constrained by fragmented and inconsistent transaction data. This study constructs a comprehensive and validated dataset of PE ownership in U.S. hospitals and offers guidance for its use in research. We integrate six major commercial deal databases to identify PE investments from 2000 to 2024, filtering for hospital-related transactions and linking targets to American Hospital Association (AHA) and Centers for Medicare and Medicaid Services (CMS) identifiers. We reconcile duplicate records, expand system-level deals to individual hospitals, and manually verify uncertain matches, deal dates, and exit events. The final dataset includes 141 unique PE deals involving 555 short-term acute care hospitals, corresponding to 721 hospital-deal observations. We document substantial variation across data sources in deal coverage, classification, and reporting level, showing that reliance on a single source can lead to incomplete or biased samples. Linking transactions to consistent hospital identifiers also requires extensive validation due to system-level reporting and identifier changes over time. Overall, the harmonized dataset and workflow provide a transparent and replicable foundation for studying PE ownership in the U.S. hospital sector.

Working Papers

When Buy-and-Build Breaks: Serial Private Equity Acquisitions in the Hospital Industry [Draft] [SSRN]

Selected Presentations: AFA Poster Session 2026, MFA Annual Meeting 2026, EFA Annual Meeting 2026, University of North Carolina at Greensboro 2026, Federal Reserve Bank of Kansas City 2026, AKFA Joint Conference 2026, SWFA Annual Conference 2026, RCF-ECGI Conference 2025, Inter-Finance PhD Seminar 2025, WEFI PhD Conference 2025, Duke University 2024

Awarded: Best PhD Paper Award, 2026 Joint Conference with Allied Korean Finance Associations (AKFA)

Abstract: I study the operational heterogeneity of private equity buyouts in the U.S. hospital industry. Classifying targets into platforms and add-ons, I document that these acquisitions serve different structural roles within a consolidated buy-and-build network. Post-acquisition, platform hospitals experience significant and persistent profitability gains, whereas local add-ons exhibit severe contractions in patient volume and profitability. Rather than reflecting managerial failure, this localized deterioration is a mechanical friction of intentional reallocation: sponsors contract local add-ons to centralize advanced clinical intensity and drive further profitability at the platform. Finding no evidence of commercial price increases, I show that system-wide value creation is driven primarily by operational restructuring; crucially, system-level health outcomes remain stable. Because private equity operations are executed differently depending on whether a target is a buy or a build, capturing their complete economic impact requires expanding the unit of analysis to the integrated system.

Privatization, Financial Distress and Spillover Effects in Hospitals (with Rui Guo) [Draft]

Selected Presentations: Inter-Finance PhD Seminar 2026

Abstract: This paper examines how acquisitions affect hospital financial distress and its spillovers in the US. We first scrutinize the selection problem, and find limited evidence that financially distressed hospitals are significantly more/less likely to be acquired. Then, we find that acquisitions do raise distress for hospitals on average and in urban markets, while it declines for rural hospitals. We explore mechanisms behind the urban and rural differences, finding that private equity acquisitions are associated with a lower share of Medicare patients and a lower commercial to Medicare price ratio, especially in urban areas, suggesting that reductions in revenue from private insurers may explain higher distress among acquired hospitals. Finally, we investigate the spillover effects of acquisitions. Acquisitions within [0,10) miles raise distress among neighboring hospitals due to stronger competitive pressure, while acquisitions within [20,30) miles reduce it by greater efficiency gains at moderate distances. We find limited evidence of spillovers on profitability, operating costs, salaries, discharges, size, or efficiency. Overall, the results show that acquisitions generate heterogeneous consequences across markets and may increase distress for hospitals that rely heavily on private insurance revenue.

The Economic Effects of a Rapid Increase in the Minimum Wage: Evidence from South Korea Experiments (with Taeyoung Doh, Kyoo il Kim, Kyungho Song, and Hwanoong Lee) (Submitted) [Draft] [SSRN] [Federal Reserve Working Paper]

Selected Presentations: KER International Conference 2023, Federal Reserve Bank of Kansas City 2022

Abstract: South Korea’s minimum wage rapidly rose from 53 percent of the median wage to 63 percent between 2017 and 2019. While the minimum wage has been increasing steadily over decades, the rapid pace in 2018-19 was largely unexpected and driven by a sudden shift in the political environment. We study the economic effects of this minimum wage hike on employment, wages, and labor productivity using South Korean manufacturing firm data, which comprehensively covers all manufacturing firms with 10 or more employees. We find a significant negative employment (3% decline in domestic employment) effect of the minimum wage hike for 2018-19 compared with its modest increase in 2015-17, as the fraction of firms exposed to the minimum wage shock substantially increased and these firms adjusted to the shock through both intensive margins (layoffs) and extensive margins (plant closings). Adjustments through extensive margins jumped up at firms whose exposure to the minimum wage hike is in the right tail. The negative employment effect is also confirmed in our supplementary analysis using population-level administrative data on firms in the service sector. At the same time, labor productivity and wages increased more for manufacturing firms with greater exposure to the minimum wage. Our empirical findings are consistent with a task-based production model with firm-level heterogeneity emphasizing the substitution between low skill labor and other production factors.

Works in Progress

Do Private Equity Acquisitions Transform Healthcare Information Technology Utilization? (with Nan Clement and Ryan McDevitt)

Selected Presentations: Annual Conference of the American Society of Health Economists 2026

Abstract: IT adoption in U.S. hospitals remains uneven despite its potential to improve coordination and efficiency. This paper examines whether private equity (PE) ownership shapes hospitals’ IT investment strategies. Using a harmonized dataset of PE hospital acquisitions (Kim et al., 2026) combined with hospital-level IT measures, we find that PE ownership leads to a targeted pattern of adoption. After PE entry, hospitals are more likely to adopt enterprise master patient indexes (EMPI), cost accounting systems, and operating-room scheduling software relative to non-acquired acute-care hospitals. EMPI and cost accounting enable patient- and service-level margin analysis, while OR scheduling improves throughput in high-margin units, together supporting revenue maximization and cost efficiency. PE acquisition also accelerates adoption of clinical documentation tools prior to the HITECH Act. Overall, the findings suggest that PE ownership drives selective technological modernization aligned with operational and financial performance goals, rather than broad-based IT transformation.

Federal Reserve Publications

Doh, T., Kim, S., & Yang, S. K. (2021). How You Say It Matters: Text Analysis of FOMC Statements Using Natural Language Processing. Economic Review-Federal Reserve Bank of Kansas City, 106(1), 25-40. [Paper]

Çakır Melek, N., & Kim, S. (2021). Cell Phone Data Suggest Persistent Differences in Work from Home by Income, Race, and Education during the Pandemic. Economic Bulletin-Federal Reserve Bank of Kansas City, (March 31, 2021), 1-4. [Paper]

Kahn, G. A., & Kim, S. (2020). Navigating the Decade Ahead: Implications for Monetary Policy: An Introduction to the Bank’s 2020 Economic Symposium. Proceedings-Economic Policy Symposium-Jackson Hole (pp. xvii-xxix). [Paper]