Jeongmin "Mina" Lee's website

Hello! I'm an assistant professor in the finance department at the Olin Business School of Washington University in St. Louis.

I work on market microstructure and banking.


Download the PDF here

Working Papers

  1. When Are Financial Markets Perfectly Competitive? with Pete Kyle [September 2018]
    • We study competitiveness of financial markets in a one-period model, in which traders speculate on private information and hedge endowment shocks. Developing and fully characterizing a new measure of market competitiveness, we find that market becomes perfectly competitive if and only if the number of traders approaches infinity and speculation becomes negligible relative to hedging. While perfect competition – the key assumption for rational expectations equilibrium – is a strong condition, we show when it can be made innocuous and when it cannot. We discuss further implications of market competitiveness for the measurement of liquidity and the real-world financial market design.
    • Supersedes Information and Competition with Speculation and Hedging
  2. The Opportunity Cost of Collateral with Jason Donaldson and Giorgia Piacentino [September 2018]
    • We develop a dynamic model of borrowing and lending in the interbank market, in which banks fund investments through short-term collateralized debt, like repos. This debt is not a perfect substitute for cash: lending banks may not be able to convert their loans to cash to fund their own investments. Hence, lending comes with an opportunity cost that generates positive spreads even absent any credit risk. The opportunity cost channel gives a new explanation for why credit is tight in crises and loose before- hand. Through banks’ collateral constraints, the opportunity cost also determines asset demand and prices, creating a feedback loop that can result in multiple, welfare-ranked equilibria. High-leverage equilibria are inefficient in booms; hence, countercyclical capital regulation can improve welfare.
    • Supersedes Collateral Circulation and Repo Spreads

Publications and Forthcoming

  1. Toward a Fully Continuous Exchange, with Pete Kyle; Oxford Review of Economic Policy (Forthcoming)
    • We propose a new market design for a securities exchange to level the playing field for all traders.


Investments: Undergraduate/MBAs

Other things


Email: jlee89(at)wustl(dot)edu

Phone: 314-935-8177

Office: Simon Hall, Room 212,

One Brookings Drive, St. Louis, MO 63130-4899

At the São Jorge Castle in Lisbon, Portugal. 20170822.

With my parents and Lee in Washington DC. 20170609.

From The Last Daughter by Elena Ferrante. 20170903.