The Effect of Common Ownership and Input-Output networks: The Case of the Spanish Economy

We quantify a parsimonious model of oligopolistic competition with common ownership in input–output networks. Using Spanish data on demand, ownership, and input–output linkages, we estimate the overall welfare effect of common ownership. Input–output linkages introduce a theoretical channel through which common ownership could improve welfare. We find that this channel exists but is not strong enough to offset the reduction in competition: common ownership has a negative welfare effect, though weaker than in the absence of input–output linkages. Finally, we introduce a parameterized ownership separation to compute a firm-level index of the anti-competitiveness of common ownership.