Exploring Competition in Digital Markets: Meet Economics PhD Student Kyungho Lee

Lee traces his interest in economics to econometrics courses he took as an undergraduate at Seoul National University, illustrating how economic theory and real-world behavior could be studied together in a rigorous way.

“If you have data, you can examine people’s behavior,” Lee said. “You can ultimately understand more how markets work.”

These early interests led him to conduct his own research, including an undergraduate empirical project on minimum wage hikes in South Korea. After completing a master’s degree at Seoul National University, Lee was drawn to Yale in part by his advisor, Yoon-Jae Whang PhD ’91, who spoke highly of the program’s academic rigor and collegial environment. Over time, he developed a broader agenda focused on technology and competition: how new technologies affect markets, how large firms use them to shape everyday economic life, and what society gains or loses in the process.

Lee’s current main research project centers on Fulfillment by Amazon (FBA), the company’s logistics service for third-party sellers. For Lee, the project begins with a simple but important observation: Amazon is not just a marketplace connecting buyers and sellers. It also controls storage, shipping, and delivery for many of the businesses that rely on its platform.

That structure has become central to antitrust debates. Lee said the project grew in part out of the Federal Trade Commission’s case against Amazon, which raised questions about whether the company’s logistics network may shape or limit competition across platforms. In particular, he became interested in how Amazon’s logistics integration affects both consumers and sellers, and whether it changes sellers’ incentives to list products elsewhere.

To study those questions, Lee built his own dataset linking sellers and products across Amazon and Walmart, combining data on prices, product characteristics, and sellers’ fulfillment choices. His early findings suggest that Amazon’s logistics fees are passed through to consumers at meaningful rates. They also suggest that sellers who use FBA may be less likely to join competing platforms such as Walmart, in part because inventory stored in Amazon’s facilities is harder to use elsewhere. Lee is now working to better understand the causal relationship behind that pattern.

“I want to find what is pro-competitive, what is anti-competitive, and what is the right policy intervention, if it is necessary,” Lee said.

Another major project, joint work with Sukjin Han (University of Bristol), examines copyright and competition through a very different market: fonts. He describes fonts as a kind of “fruit fly” for studying copyright: simple enough to analyze clearly, but rich enough to shed light on broader policy questions.

Using data from MyFonts.com, the world's largest online font marketplace, Lee and Han trained a neural network to measure visual similarity between fonts in a way that better tracks human perception. They then used that measure in a structural model of supply and demand to study how copyright protection affects entry, imitation, and consumer welfare, including in a world where generative AI makes imitation easier and cheaper.

Their findings point to a nuanced conclusion. Stronger copyright protection can improve consumer welfare, but too much protection can discourage entry and make the marketplace worse. More broadly, the project reflects Lee’s interest in bringing new forms of data and new empirical tools to longstanding policy questions.

Although Lee came to Yale with broad interests in economics and technology, his work on antitrust and Amazon took shape through coursework, conversations with faculty, and a research culture that encourages students to pursue questions with clear policy relevance.

That environment mattered personally as well. Coming to the United States from South Korea for a PhD was a major transition, and Lee said Yale’s collegiality stood out early. He wanted to be part of a community where relationships with faculty and fellow students felt accessible, not distant. Weekly dinners with fellow graduate students and office-mates have become one of the steady rhythms of graduate life, and faculty have also made an effort to include graduate students in the department’s broader intellectual and social community.

Looking ahead, Lee hopes his research can help modernize copyright and antitrust policy for digital markets. Doing so, he argues, will require a clearer understanding of how technology reshapes competition and where policy intervention is actually needed. At the core of his work is a broader question: when markets change, how should policy keep up?

See Kyungho Lee's full research portfolio here.