We characterize the class of symmetric two-player games in which tit-for-tat cannot be beaten even by very sophisticated opponents in a repeated game. It turns out to be the class of exact potential games. More generally, there is a class of simple imitation rules that includes tit-for-tat but...

We study cartels that operated in the US generic drug industry, leveraging quarterly Medicaid data from 2011-2018 and a difference-in-differences approach comparing the evolution of prices of allegedly collusive drugs with a group of competitive control drugs. Our analysis highlights (i) the...

The seminal work of Fudenberg and Tirole (1985) on how preemption erodes the value of an option to wait raises general questions about the relation between models in discrete and continuous time and thus about the interpretation of its central result, relying on an "infinitely fine grid". Here...

This paper presents a new method for estimating discrete games based on bounds of conditional choice probabilities. The method does not require solving the game and is scalable to models with many firms and many discrete decisions. We apply the method to study merger effects on firm entry and...

Horizontal shareholding exists when significant shareholders have stock in horizontal competitors. (It is often imprecisely called "common shareholding," but that term can also apply when shareholders own stock in two noncompeting corporations. It differs from "cross-shareholding," which...

This Article shows that new economic proofs and empirical evidence provide powerful confirmation that, even when horizontal shareholders individually have minority stakes, horizontal shareholding in concentrated markets often has anticompetitive effects. The new economic proofs show that,...

Cripps et al. (2005) conjectured that in an infinitely repeated game with two equally patient players, if there is positive probability that the players could be Stackelberg types, then equilibrium behavior would resemble a war of attrition, i.e., a two-sided reputation result would hold. In...

We present a model of repeated games in large buyer-seller networks in the presence of reputation networks via which buyers share information about past transactions. The model allows us to characterize cooperation networks - networks in which each seller cooperates (by providing high quality...