Risk arbitrage and hedging to acceptability under transaction costs

The classical discrete-time model of proportional transaction costs relies on the assumption that a feasible portfolio process has solvent increments at each step. We extend this setting in two directions, allowing convex transaction costs and assuming that increments of the portfolio process belong to the sum of a solvency set and a family of multivariate acceptable positions, e.g. with respect to a dynamic risk measure. We describe the sets of superhedging prices, formulate several no (risk) arbitrage conditions and explore connections between them. In the special case when multivariate positions are converted into a single fixed asset, our framework turns into the no-good-deals setting. However, in general, the possibilities of assessing the risk with respect to any asset or a basket of assets lead to a decrease of superhedging prices and the no-arbitrage conditions become stronger. The mathematical techniques rely on results for unbounded and possibly non-closed random sets in Euclidean space.

     

Macroeconomic effects of corporate default crisis: A long-term perspective

Using an extensive data set on corporate bond defaults in the US from 1866 to 2010, we study the macroeconomic effects of bond market crises and contrast them with those resulting from banking crises. During the past 150 years, the US has experienced many severe corporate default crises in which 20–50% of all corporate bonds defaulted. Although the total par amount of corporate bonds has at times rivaled the amount of bank loans outstanding, we find that corporate default crises have far fewer real effects than do banking crises. These results provide empirical support for current theories that emphasize the unique role that banks and the credit and collateral channels play in amplifying macroeconomic shocks.     

Intragroup transfers,intragroup diversification and their risk assessment

When assessing group solvency, an important question is to what extent intragroup transfers may be taken into account, as this determines to which extent diversification can be achieved. We suggest a framework to explicitly describe the families of admissible transfers that range from the free movement of capital to excluding any transactions. The constraints on admissible transactions are described as random closed sets. The paper focuses on the corresponding solvency tests that amount to the existence of acceptable selections of the random sets of admissible transactions.     

Collusion, Exclusion, and Inclusion in Random-Order Bargaining

This paper examines the profitability of three types of integration in a cooperative game solved by a random-order value ( e.g. the Shapley value). Collusion between players  i  and  j  is a contract merging their resources in the hands of one of them, say  i  . This contract can be represented as a combination of exclusion, which lets  i  exclude  j  's resource but not use it himself, and inclusion, which lets  i  use  j  's resource but not exclude  j  from it. This representation yields a third-difference condition on the characteristic function that determines the profitability of collusion, generalizing existing results for specific games. Namely, collusion is profitable [unprofitable] when the complementarity of the colluding players is reduced [increased] by other players.     

Coordination and discrimination in contracting with externalities: divide and conquer?

The paper studies bilateral contracting between N agents and one principal, whose trade with each agent generates externalities on other agents. It examines the effects of prohibiting the principal from (i) coordinating agents on her preferred equilibrium, and (ii) making different contracts available to different agents. These effects depend on whether an agent is more or less eager to trade when others trade more. The prohibitions reduce the aggregate trade in the former case, and have little or no effect in the latter case. The inefficiencies under different contracting regimes are linked to the sign of the relevant externalities, and are shown to be typically reduced by both prohibitions.