Multi-Market Cournot Equilibria with Heterogeneous Resource-Constrained Firms
Prof. Martin Haugh
Associate Professor of Analytics and Operations Research
Department of Analytics, Marketing & Operations
Imperial College Business School
We study Cournot competition among firms in a multi-market framework where each of the firms face different budget / capacity constraints. We assume independent linear inverse demand functions for each market, and completely characterize the resulting unique equilibrium. Specifically, we introduce the notions of augmented and cutoff budgets for firms and markets, respectively. We show, for example, that firm i operates in market j if and only if firm i’s augmented budget is greater than market j’s cutoff budget. We also study the properties of the equilibrium as a function of the number of firms N while keeping the aggregate budget fixed. In a numerical study, we show that increasing N increases the total output across all markets although this monotonicity can fail to hold at the individual market level. Similarly, we show that that while the firms’ cumulative payoff decreases in N, the consumer surplus and social surplus increase in N. Finally, we consider extensions to the case of non-linear inverse demand functions.
(Based on joint work with Rene Caldentey)