We formalize the Marshallian idea that when the proportion of income spent on any commodity is small then the income effects are small. If n is the number of goods, we show, under certain assumptions on preferences and prices, that the order of magnitude of the norm of the income derivative of demand is 1/√n. As a corollary we get that for the case of a single price change the percentage error in approximating the Hicksian Deadweight Loss by its Marshallian counterpart goes to zero at least at the rate 1/√n and that demand is downward sloping for n large enough.

A standard demand-deposit contract in which individuals are entitled to their full deposit at any time provided the bank is solvent is analyzed in a context in which there are no exogenous events on which agents condition their behavior and a unique equilibrium involving a bank run with positive probability is shown to exist.

The strategic incentives, with respect to the choice of price policy in spatial competition, are analyzed in a duopoly model. Price discrimination emerges as the unique equilibriu m outcome in games with either simultaneous choice of policy and pric e or sequential choice where firms may commit first to uniform mill p ricing before the actual market stage. Nevertheless, profits may be h igher with uniform pricing. The authors' models are applied to analyz e some common business practices that arise in geographical pricing, like the basing point system, and in the pricing of varieties or opti ons from a base product in a product-differentiation context.