Dynamic Trading: Price Inertia and Front-Running∗ Yuliy Sannikov Andrzej Skrzypacz Graduate School of Business Graduate School of Business Stanford University Stanford University
[email protected] [email protected] December 7, 2016 Abstract We build a linear-quadratic model to analyze trading in a market with pri- vate information and heterogeneous agents. Agents receive private taste/inventory shocks and trade continuously. Agents differ in their need for trade as well as the cost to hold excessive inventory. In equilibrium, trade is gradual. Trading speed depends on the number and market power of participants, and trade among large market participants is slower than that among small ones. Price has momentum due to the actions of large traders: it drifts down if the sell- ers have greater market power than buyers, and vice versa. The model can also answer welfare questions, for example about the social costs and benefits of market consolidation. It can also be extended to allow private information about common value. 1 Introduction. A market with heterogeneous investors { large institutions, small retail investors, liquidity providers and high-frequency traders { presents many puzzles. What de- termines the speed of trading? What is the link between microstructure and time series properties of prices, such as momentum and excess volatility? What is the price impact of large trades, and how much does it matter for optimal execution of transactions? What about phenomena such as front-running { are they detrimental ∗We are grateful to seminar participants at Yale, the New York Fed, Cambridge, Stanford, Latin American Econometric Society Meetings, LBS, Harvard, MIT, Northwestern, Chicago, NYU, Georgetown, Duke, the University of Helsinki, the University of Lausanne, Caltech, Collegio Carlo Alberto and Universidad de Chile for helpful comments.