"Finitely Repeated Games with Small Side Payments"

This paper investigates repeated games with perfect monitoring, where the number of repetition is finite, and the discount factor is far less than unity. Players can make a side payment contract, but their liability is severely limited. The history of play may not necessarily be verifiable. With positive interest rate of the contractible asset, we show that, in spite of limited liability and verifiability, efficiency is sustainable in that there exist a contract and an efficient perfect equilibrium in its associated game, and that efficiency is even uniquely sustainable if there exists the unique one-shot Nash equilibrium. In partnership games, efficiency is uniquely and approximately sustainable, even if the interest rate equals zero. In partnership games with two players and positive interest rate, efficient sustainability is robust to renegotiation-proofness on the terms of explicit contracting as well as implicit agreements.

Cooperation cannot be sustained in a discounted repeated prisoners' dilemma with patient short and long run players

This study presents a modified version of the repeated discounted prisoners' dilemma with long and short-run players. In our setting a short-run player does not observe the history that has occurred before he was born, and survives into next phases of the game with a probability given by the current action profile in the stage game. Thus, even though it is improbable, a short-run player may live and interact with the long-run player for infinitely long amounts of time. In this model we prove that under a mild incentive condition on the stage game payoffs, the cooperative outcome path is not subgame perfect no matter how patient the players are. Moreover with an additional technical assumption aimed to provide a tractable analysis, we also show that payoffs arbitrarily close to that of the cooperative outcome path, cannot be obtained in equilibrium even with patient players

A Computational View of Market Efficiency

We propose to study market efficiency from a computational viewpoint. Borrowing from theoretical computer science, we define a market to be \emph{efficient with respect to resources $S$} (e.g., time, memory) if no strategy using resources $S$ can make a profit. As a first step, we consider memory-$m$ strategies whose action at time $t$ depends only on the $m$ previous observations at times $t-m,...,t-1$. We introduce and study a simple model of market evolution, where strategies impact the market by their decision to buy or sell. We show that the effect of optimal strategies using memory $m$ can lead to "market conditions" that were not present initially, such as (1) market bubbles and (2) the possibility for a strategy using memory $m' > m$ to make a bigger profit than was initially possible. We suggest ours as a framework to rationalize the technological arms race of quantitative trading firms

Sustainable monetary policy and inflation expectations

The author shows that the short-term nominal interest rate can anchor private-sector expectations into low inflation more precisely, into the best equilibrium reputation can sustain. He introduces nominal asset markets in an infinite horizon version of the Barro-Gordon model. The author then analyzes the subset of sustainable policies compatible with any given asset price system at date t = 0. While there are usually many sustainable inflation paths associated with a given set of asset prices, the best sustainable inflation path is implemented if and only if the short-term nominal bond is priced at a certain discount rate. His results suggest that policy frameworks must also be evaluated on their ability to coordinate expectations.Inflation (Finance) ; Interest rates ; Asset pricing

Market Efficiency and Price Formation When Dealers are Asymmetrically Informed

We consider the effect of asymmetric information on the price formation process in a quote-driven market where one market maker receives a private signal on the security fundamental.A model is presented where market makers repeatedly compete in prices: at each stage a bid-ask auction occurs and the winner trades the security against liquidity traders.We show that at equilibrium the market is not strong-form efficient until the last stage.We characterize a reputational equilibrium in which the informed market maker will affect market beliefs, and possibly misleads them.At this equilibrium, a price leadership effect arises, quotes are never equal to the expected value of the asset given the public information, the informed market maker expected payoff is positive and the rate of price discovery increases in the last stages of trade before the information becomes public.pricing;information;market structure;capital markets

Market efficiency and Price Formation when Dealers are Asymmetrically Informed

We consider the effect of asymmetric information on price formation process in a quote-driven market where one market maker receives a private signal on the security's fundamental. A model is presented where market makers repeatedly compete in prices: at each stage a bid-ask auction occurs and the winner trades the security against liquidity traders. We show that at equilibrium the market is not strong-form efficient until the last stage. We characterize a reputational equilibrium in which the informed market maker will aspect market beliefs, possibly misleading them, in the sense that he will push the uninformed participants to think the value of the risky asset is different from the realized one. At this equilibrium a price leadership effect arises, quotes are never equal to the expected value of the asset given the public information, the informed market maker expected payoff is positive and the information revelation speed is slower than in an analogous order-driven market.bid-ask prices; asymmetric information; repeated auction; insider trading