Market impact: a systematic study of the high frequency options market

This paper deals with a fundamental subject that has seldom been addressed in recent years, that of market impact in the options market. Our analysis is based on a proprietary database of metaorders—large orders that are split into smaller pieces before being sent to the market—on one of the main Asian markets. In line with our previous work on the equity market [Said, E., Bel Hadj Ayed, A., Husson, A. and Abergel, F., Market impact: A systematic study of limit orders. Mark. Microstruct. Liq., 2018, 3(3&4), 1850008.], we propose an algorithmic approach to identify metaorders, based on some implied volatility parameters, the at the money forward volatility and at the money forward skew. In both cases, we obtain results similar to the now well-understood equity market: Square-Root Law, Fair Pricing Condition and Market Impact Dynamics.     

Homotopy methods to compute equilibria in game theory

This paper presents a survey of the use of homotopy methods in game theory. Homotopies allow for a robust computation of game-theoretic equilibria and their refinements. Homotopies are also suitable to compute equilibria that are selected by various selection theories. We present the relevant techniques underlying homotopy algorithms. We give detailed expositions of the Lemke–Howson algorithm and the van den Elzen–Talman algorithm to compute Nash equilibria in 2-person games, and the Herings–van den Elzen, Herings–Peeters, and McKelvey–Palfrey algorithms to compute Nash equilibria in general n-person games. We explain how the main ideas can be extended to compute equilibria in extensive form and dynamic games, and how homotopies can be used to compute all Nash equilibria.     

Kinky perceived demand curves and Keynes–Negishi equilibria

The label "Keynes–Negishi equilibria" is attached here to equilibria in a monetary economy with imperfectly competitive product and labor markets where business firms and labor unions hold demand perceptions with kinks: as posited in Negishi's 1979 book Microeconomic Foundations of Keynesian Macroeconomics . Such equilibria are defined in a general equilibrium model, and shown to exist. Methodological implications are briefly discussed in a concluding section.     

Collusion and group lending with adverse selection

In an environment with correlated returns, this paper characterizes optimal lending contracts when the bank faces adverse selection and borrowers have limited liability. Group lending contracts are shown to be dominated by revelation mechanisms which do not use the ex post observability of the partners' performances. However, when collusion between borrowers under complete information is allowed, group lending contracts are optimal in the class of simple revelation mechanisms (which elicit only the borrower's own private information) and remain useful with extended revelation mechanisms.     

Collusion, Delegation and Supervision with Soft Information

This paper shows that supervision with soft information is valuable whenever supervisors and supervisees collude under asymmetric information and proceeds then to derive an Equivalence Principle between organizational forms of supervisory and productive activities. We consider an organization with an agent privately informed on his productivity and a risk averse supervisor getting signals on the agent's type. In a centralized organization, the principal can communicate and contract with both the supervisor and the agent. However, these two agents can collude against the principal. In a decentralized organization, the principal only communicates and contracts with the supervisor who in turn sub-contracts with the agent. We show that the two organizations achieve the same outcome. We discuss this equivalence and provide various comparative statics results to assess the efficiency of supervisory structures.     

Intertemporal market division:: A case of alternating monopoly

In this paper, we report on an equilibrium with market dominance that exists in a simple two-firm model that features neither entry barriers nor sophisticated punishment strategies. This equilibrium induces an intertemporal market division in which the two firms alternate as monopolists - despite the fact that the model also sustains a Cournot duopoly. Even when initially both firms are active in the market, the alternating monopoly reveals itself rather quickly. Moreover, it Pareto dominates the Cournot equilibrium - as it is close to the cartel outcome. Several examples of what well may be such alternating monopolies are presented.     

Sequential location equilibria under incomplete information

Summary We consider a simple model of incomplete information in location theory. Two firms compete in a two stage framework: a sequential location stage and a price competition stage. Firm 1 knows both its own constant marginal cost technology and that of Firm 2, whereas the latter has incomplete information about firm 1's technology. The location stage turns out to be a monotonic signaling game and theunique D1 equilibrium is a pure strategy separating equilibrium if firm 1's cost advantage is below some bound, and otherwise a pooling equilibrium if the prior probability that Firm 1 is of the low cost type is high, or a semi-pooling equilibrium if it is low. This surprising result is due to the fact that the location gap between the two types of Firm 1 is bounded because of natural economic reasons, which may prevent the separation of the two types. Hence, incomplete information matters: the equilibrium locations differ quite significantly from the full information equilibrium locations.We would like to thank an anonymous referee for very helpful comments and also the participants in seminars at GREQE (Marseille), Université de Montréal, UBC, HEC (Paris), in the Location Theory session of the World Congress of the Econometric Society (Barcelona) and in the Game Theory Conference at the University of Western Ontario for their comments. We remain, of course, solely responsible for the content of the paper. Financial support from FCAR (Québec), SSHRCC (Canada) and CNRS (France) is gratefully acknowledged.     

Incentive Regulation and The Cost Structure of The Local Telephone Exchange Network

This paper combines an engineering process model of the cost of local exchange telecommunications firms with an analytical model of optimal incentive regulation (with ex post cost observability), to study empirically the properties of the optimal regulatory mechanism. Relying on detailed properties of the cost function, we examine three issues: (i) the extent of natural monopoly when informational rents associated with regulation are taken into account; (ii) the extent of incentive correction, which expresses the divergence of pricing under the optimal mechanism from optimal pricing under complete information; (iii) the implementation of optimal regulation through a menu of linear contracts. Our findings are that, for fixed territory, strong economies of scale allow local exchange telecommunications to retain monopoly characteristics even when the (informational) costs of regulation are properly accounted for, the incentive correction term is small in magnitude, and that optimal regulation can be well approximated through relatively simple linear contracts.