Group Purchasing Organizations (GPOs) increasingly gain in importance with respect to the supply of pharmaceutical products and frequently use multiple or exclusive rebate contracts to exercise market power. Based on a Hotelling model of horizontal and vertical product differentiation, we...

A budget-constrained buyer wants to purchase items from a shortlisted set. Items are differentiated by quality and sellers have private reserve prices for their items. Sellers quote prices strategically, inducing a knapsack game. The buyer's problem is to select a subset of maximal quality. We...

A budget-constrained buyer wants to purchase items from a shortlisted set. Items are differentiated by quality and sellers have private reserve prices for their items. Sellers quote prices strategically, inducing a knapsack game. The buyer's problem is to select a subset of maximal quality. We...