We develop a version of the fundamental theorem of asset pricing for discrete-time markets with proportional transaction costs and model uncertainty. A robust notion of no-arbitrage of the second kind is defined and shown to be equivalent to the existence of a collection of strictly consistent price systems.

In this note we show that the results developed in Singh and Vives (1984) are sensitive to the duopoly assumption (Rand Journal of Economics 15, 546-554). If there are more than two firms, prices may be higher under price competition than under quantity competition. This will be the case if quality differences are large and goods are complements. If goods are substitutes, high-quality firms may...

ELECTIONS AND ASSET PRICING: THE POLITICALLY SENSITIVE EQUITY OF US MILITARY CONTRACTORS by

In contrast with the classical models of frictionless financial markets, market models with proportional transaction costs, even satisfying usual no-arbitrage properties, may admit arbitrage opportunities of the second kind. This means that there are self-financing portfolios with initial endowments laying outside the solvency region but ending inside. Such a phenomenon was discovered by M. Rás...

Focus is here on coalitional games among economic agents plagued by aggregate pollutions of diverse sorts. Defecting players presumably pollute more than others. Then, granted convex preferences and technologies, the core is proven nonempty. In fact, under natural assumptions, a specific, computable core solution comes in terms of shadow prices on the said aggregates. Such prices may, in large ...

For portfolio choice problems with proportional transaction costs, we discuss whether or not there exists a shadow price, i.e., a least favorable frictionless market extension leading to the same optimal strategy and utility. By means of an explicit counter-example, we show that shadow prices may fail to exist even in seemingly perfectly benign situations, i.e., for a log-investor trading in an...