Multibidding game under uncertainty

This paper considers situations in which a group of agents has to decide whether to carry out a given public project or its alternative when agents hold private information. I use the budget-balanced multibidding mechanism (Pérez-Castrillo and Wettstein in Am Econ Rev 5:1577–1587, 2002) according to which the game to be played by participants has only one stage and simple rules that can be applied in a wide range of situations. It is shown that the symmetric equilibria of the multibidding game deliver ex-post efficient outcomes if the number of agents is two, for any underlying symmetric distribution characterizing uncertainty, or is very large.     

Entry and Merger in Commercial Fishing with Multiple Markets

Received May 23, 2001; revised version received October 22, 2001     

Beyond cash-additive risk measures: when changing the numéraire fails

We discuss risk measures representing the minimum amount of capital a financial institution needs to raise and invest in a pre-specified eligible asset to ensure it is adequately capitalized. Most of the literature has focused on cash-additive risk measures, for which the eligible asset is a risk-free bond, on the grounds that the general case can be reduced to the cash-additive case by a change of numéraire. However, discounting does not work in all financially relevant situations, especially when the eligible asset is a defaultable bond. In this paper, we fill this gap by allowing general eligible assets. We provide a variety of finiteness and continuity results for the corresponding risk measures and apply them to risk measures based on value-at-risk and tail value-at-risk on L ^p spaces, as well as to shortfall risk measures on Orlicz spaces. We pay special attention to the property of cash subadditivity, which has been recently proposed as an alternative to cash additivity to deal with defaultable bonds. For important examples, we provide characterizations of cash subadditivity and show that when the eligible asset is a defaultable bond, cash subadditivity is the exception rather than the rule. Finally, we consider the situation where the eligible asset is not liquidly traded and the pricing rule is no longer linear. We establish when the resulting risk measures are quasiconvex and show that cash subadditivity is only compatible with continuous pricing rules.