Collusion in Brokered Markets

John William Hatfield; Scott Duke Kominers; Richard  Lowery

Working Paper | HBS Working Paper Series | 2019

Collusion in Brokered Markets

by John William Hatfield, Scott Duke Kominers and Richard Lowery

Abstract

The U.S. residential real estate agency market presents a puzzle for economic theory: commissions on real estate transactions have remained constant and high for decades even though agent entry is frequent and agents’ costs of providing service are low. We model the real estate agency market, and other brokered markets, via repeated extensive form games; in our game, brokers first post prices for customers and then choose which agents on the other side of the market to work with. We show that prices appreciably higher than the competitive prices can be sustained (for a fixed discount factor) regardless of the number of brokers; this is done through strategies that condition willingness to transact with each broker on that broker’s initial posted prices. Our results can thus rationalize why brokered markets exhibit pricing high above marginal cost despite fierce competition for customers; moreover, our model can help explain why agents and platforms who have tried to reduce commissions have had trouble entering the market.

Keywords: real estate; ＂Repeated games＂; collusion; antitrust; brokered markets; Game Theory; Real Estate Industry;

Language: English

Format: Print

77 pages

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Citation:

Hatfield, John William, Scott Duke Kominers, and Richard Lowery. "Collusion in Brokered Markets." Harvard Business School Working Paper, No. 20-023, September 2019.

We introduce an empirical framework for models of matching with imperfectly transferable utility and unobserved heterogeneity in tastes. Our framework allows us to characterize matching equilibrium in a flexible way that includes as special cases the classic fully- and non-transferable utility models, collective models, and settings with taxes on transfers, deadweight losses, and risk aversion. We allow for the introduction of a very general class of unobserved heterogeneity on agents' preferences. Under minimal assumptions, we show existence and uniqueness of equilibrium. We provide two algorithms to compute the equilibria in our model. The first algorithm operates under any structure of heterogeneity in preferences. The second algorithm is more efficient, but applies only in the case when random utilities are logit. We show that the log-likelihood of the model has a particularly simple expression and we compute its derivatives. As an application, we build a model of marriage with two-sided preferences over the partner type and private consumption. We estimate our model using the 2013 "Living Costs and Food Survey" database.

Article | Management Science | December 2019

Patent Trolls: Evidence from Targeted Firms

Lauren Cohen, Umit Gurun and Scott Duke Kominers

We provide the first large-sample evidence on the behavior and impact of nonpracticing entities (NPEs) in the intellectual-property space. We find that, on average, NPEs appear to behave as opportunistic “patent trolls.” NPEs sue cash-rich firms and target cash in business segments unrelated to alleged infringement at essentially the same frequency as they target cash in segments related to alleged infringement. By contrast, cash is neither a key driver of intellectual-property lawsuits by practicing entities (e.g., IBM and Intel) nor of any other type of litigation against firms. We find further suggestive evidence of NPE opportunism: targeting of firms that have reduced ability to defend themselves, repeated assertions of lower-quality patents, increased assertion activity nearing patent expiration, and forum shopping. We find, moreover, that NPE litigation has a real negative impact on innovation at targeted firms: firms substantially reduce their innovative activity after settling with NPEs (or losing to them in court). Meanwhile, we neither find any markers of significant NPE pass-through to end innovators nor of a positive impact of NPEs on innovation in the industries in which they are most prevalent.

Keywords: Patent trolls; patents; innovation; Patents; Lawsuits and Litigation; Ethics; Innovation and Invention;

Citation:

Cohen, Lauren, Umit Gurun, and Scott Duke Kominers. "Patent Trolls: Evidence from Targeted Firms." Management Science 65, no. 12 (December 2019): 5461–5486. (Cited in the United States Federal Trade Commission Report on Patent Assertion Entities, 2016.) View Details

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Various forms of substitutability are essential for establishing the existence of equilibria and other useful properties in diverse settings such as matching, auctions, and exchange economies with indivisible goods. We extend earlier models’ definitions of substitutability to settings in which each agent can be both a buyer in some transactions and a seller in others and show that all these definitions are equivalent. We then introduce a new class of substitutable preferences that allows us to model intermediaries with production capacity. We also prove that substitutability is preserved under economically important transformations such as trade endowments, mergers, and limited liability.

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Collusion in Brokered Markets

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