Thomas Tröger

Collusion Via Resale

The English auction is susceptible to tacit collusion when post-auction inter-bidder resale is allowed. We show this by constructing equilibria where, with positive probability, one bidder wins the auction without any competition and divides the spoils by optimally reselling the good to the other bidders. These equilibria interim Pareto dominate (among bidders) the standard value-bidding equilibrium, without requiring the bidders to make any commitment on bidding behavior or post-bidding spoil-division.

Why Sunk Costs Matter for Bargaining Outcomes: An Evolutionary Approach☆

Abstract Two bargaining parties play the Nash Demand Game to share a pie whose size is determined by one partys investment decision. Various investment levels are subgame-perfect. Adding the investment decision to Youngs evolutionary bargaining model yields the following long-run outcome: efficient investment prevails and the investors share of the pie approximates die maximum of (i) the smallest share that induces efficient investment, even if the investor expects to appropriate the available pie from every inefficient investment, and (ii) half of the pie. The result favors forward induction to subgame consistency and equity theory to hold-ups. Journal of Economic Literature Classification Numbers: C78, L14.

An evolutionary analysis of insurance markets with adverse selection

Since the seminal work by Rothschild and Stiglitz on competitive insurance markets under adverse selection the problem of non-existence of equilibrium hat puzzled many economists. In this paper we approach this problem from an evolutionary point of view. In a dynamic model insurance companies remove lossmaking contracts from the market and copy profit making ones. Occasionally, they also experiment, adding new contracts or removing current ones arbitrarily. We show that the Rothschild-Stiglitz outcome arises in the long run if it cinstitutes an equilibrium in the static framework, but also if it is not an equilibrium, provides that firms only experiment with contracts in the vicinity of their current portfolio.

Matching Heterogeneous Agents with a Linear Search Technology

Steady state equilibria in heterogeneous agent matching models with search frictions have been shown to exist in Shimer and Smith (2000) under the assumption of a quadratic search technology. We extend their analysis to the commonly investigated linear search technology.

Existence of Linear Equilibria in the Kyle Model with Multiple Informed Traders

We consider Kyles market order model of insider trading with multiple informed traders and show: if a linear equilibrium exists for two different numbers of informed traders, asset payoff and noise trading are independent and have finite second moments, then these random variables are normally distributed.

A Characterization of the Distributions That Imply Existence of Linear Equilibria in the Kyle-Model

The existence of a linear equilibrium in Kyles model of market making with multiple, symmetrically informed strategic traders is implied for any number of strategic traders if the joint distribution of the underlying exogenous random variables is elliptical. The reverse implication has been shown for the case in which the random variables are independent and have finite second moments. Here we extend this result to the case in which the underlying random variables are not necessarily independent and their joint distribution is determined by its moments.

Informed-principal problem with moral hazard, risk neutrality, and no limited liability

We consider a principal–agent moral-hazard problem with risk-neutral parties and no limited liability in which the principal has private information. The principals private information creates signaling considerations that may distort the implemented outcome. These distortions can explain, e.g., efficiency wages (Beaudry, 1994) and muted incentives (Inderst, 2001). We show that in a large class of environments these distortions vanish if the principal is allowed to offer sufficiently rich contracts.

On the Existence of Linear Equilibria in the Rochet-Vila Model of Market Making

This paper derives necessary and sufficient conditions for the existence of linear equilibria in the Rochet-Vila model of market making. In contrast to most previous work on the existence of linear equilibria in models of market making, we do not impose independence of the underlying random variables. For distributions that are determined by their moments we show that a linear equilibrium exists if and only if the joint distribution of noise trade and asset payoff is elliptical.