The Hedge Fund Game

This paper examines theoretical properties of incentive contracts in the hedge fund industry. We show that it is very difficult to structure incentive payments that distinguish between unskilled managers, who cannot generate excess market returns, and skilled managers who can deliver such returns. Under any incentive scheme that does not levy penalties for underperformance, managers with no investment skill can game the system so as to earn (in expectation) the same amount per dollar of funds under management as the most skilled managers. We consider various ways of eliminating this “piggy-back effect,” such as forcing the manager to hold an equity stake or levying penalties for underperformance. The nature of the derivatives market means that none of these remedies can correct the problem entirely.incentive contracts, excess returns

Using CRISPR to Genetically Engineer Two Genes Involved in Gonadogenesis in the Model Organism C. elegans

C. elegans is a nematode model organism commonly used in research because of its small size and similarity to humans. Of the known protein sequences of C. elegans, 40%-80% have human homologous genes, making C. elegans an ideal organism for study of human proteins (Lai et al. 2000). Additionally, there are two sexes of C. elegans, male and hermaphrodite. Of the two sexes, this research focuses on the males, especially the development of the gonad and the genes involved in this process. Two genes were chosen for study, C10E2.6 and pig-1, based on essentiality and mRNA expression during gonadogenesis. An essential gene is defined as a gene that is necessary for the organism to survive. The mRNA expression of the genes was observed to be higher in both the male and hermaphrodite gonads during development when compared to the mRNA expression in the rest of the organism. DNA constructs, including gRNA (guide RNA) and a homologous repair construct, were designed to study the genes. In this research, CRISPR will be used to genetically alter the worms so that the gene products of the aforementioned genes are fused with GFP. Future research will allow for the study of the genes\u27 specific role in gonadal development through the study of the effects of the absence of the gene products in the worm. Even further, it is possible that some parts of gonad formation may be a conserved process between species, perhaps shedding light on this process in mammals

Regret testing: learning to play Nash equilibrium without knowing you have an opponent

A learning rule is uncoupled if a player does not condition his strategy on the opponent's payoffs. It is radically uncoupled if a player does not condition his strategy on the opponent's actions or payoffs. We demonstrate a family of simple, radically uncoupled learning rules whose period-by-period behavior comes arbitrarily close to Nash equilibrium behavior in any finite two-person game.Learning, Nash equilibrium, regret, bounded rationality

The Cost of Stability in Coalitional Games

A key question in cooperative game theory is that of coalitional stability, usually captured by the notion of the \emph{core}--the set of outcomes such that no subgroup of players has an incentive to deviate. However, some coalitional games have empty cores, and any outcome in such a game is unstable. In this paper, we investigate the possibility of stabilizing a coalitional game by using external payments. We consider a scenario where an external party, which is interested in having the players work together, offers a supplemental payment to the grand coalition (or, more generally, a particular coalition structure). This payment is conditional on players not deviating from their coalition(s). The sum of this payment plus the actual gains of the coalition(s) may then be divided among the agents so as to promote stability. We define the \emph{cost of stability (CoS)} as the minimal external payment that stabilizes the game. We provide general bounds on the cost of stability in several classes of games, and explore its algorithmic properties. To develop a better intuition for the concepts we introduce, we provide a detailed algorithmic study of the cost of stability in weighted voting games, a simple but expressive class of games which can model decision-making in political bodies, and cooperation in multiagent settings. Finally, we extend our model and results to games with coalition structures.Comment: 20 pages; will be presented at SAGT'0

Contagion in financial networks

The recent financial crisis has prompted much new research on the interconnectedness of the modern financial system and the extent to which it contributes to systemic fragility. Network connections diversify firms' risk exposures, but they also create channels through which shocks can spread by contagion. We review the extensive literature on this issue, with the focus on how network structure interacts with other key variables such as leverage, size, common exposures, and short-term funding. We discuss various metrics that have been proposed for evaluating the susceptibility of the system to contagion and suggest directions for future research

Stochastic learning dynamics and speed of convergence in population games

We study how long it takes for large populations of interacting agents to come close to Nash equilibrium when they adapt their behavior using a stochastic better reply dynamic. Prior work considers this question mainly for 2 × 2 games and potential games; here we characterize convergence times for general weakly acyclic games, including coordination games, dominance solvable games, games with strategic complementarities, potential games, and many others with applications in economics, biology, and distributed control. If players' better replies are governed by idiosyncratic shocks, the convergence time can grow exponentially in the population size; moreover, this is true even in games with very simple payoff structures. However, if their responses are sufficiently correlated due to aggregate shocks, the convergence time is greatly accelerated; in fact, it is bounded for all sufficiently large populations. We provide explicit bounds on the speed of convergence as a function of key structural parameters including the number of strategies, the length of the better reply paths, the extent to which players can influence the payoffs of others, and the desired degree of approximation to Nash equilibrium

Payoff-Based Dynamics for Multiplayer Weakly Acyclic Games

We consider repeated multiplayer games in which players repeatedly and simultaneously choose strategies from a finite set of available strategies according to some strategy adjustment process. We focus on the specific class of weakly acyclic games, which is particularly relevant for multiagent cooperative control problems. A strategy adjustment process determines how players select their strategies at any stage as a function of the information gathered over previous stages. Of particular interest are “payoff-based” processes in which, at any stage, players know only their own actions and (noise corrupted) payoffs from previous stages. In particular, players do not know the actions taken by other players and do not know the structural form of payoff functions. We introduce three different payoff-based processes for increasingly general scenarios and prove that, after a sufficiently large number of stages, player actions constitute a Nash equilibrium at any stage with arbitrarily high probability. We also show how to modify player utility functions through tolls and incentives in so-called congestion games, a special class of weakly acyclic games, to guarantee that a centralized objective can be realized as a Nash equilibrium. We illustrate the methods with a simulation of distributed routing over a network

How safe are central counterparties in credit default swap markets?

We propose a general framework for estimating the vulnerability to default by a central counterparty (CCP) in the credit default swaps market. Unlike conventional stress testing approaches, which estimate the ability of a CCP to withstand nonpayment by its two largest counterparties, we study the direct and indirect effects of nonpayment by members and/or their clients through the full network of exposures. We illustrate the approach for the U.S. credit default swaps market under shocks that are similar in magnitude to the Federal Reserve’s stress tests. The analysis indicates that conventional stress testing approaches may underestimate the potential vulnerability of the main CCP for this market