“…Finally, the existence of strategic interaction between downstream firms allows for the emergence of asymmetric mode-ofoperation equilibria, in which the firms choose different organisational forms even when they are ex-ante identical; this is in sharp contrast to the results obtained in the monopolistically competitive framework in which asymmetric equilibria only arise in the presence of ex-ante efficiency differences. Despite the additional complexity arising from unionisation, this result is consistent with Leahy and Montagna (2011) who show that outsourcing -by softening the investment behaviour of rivals -can be viewed as a defensive business strategy that can be the best response to rivals' choice of vertical integration. However, the presence of unionisation, by endogenising the wage paid by firms, results in this model in the emergence of asymmetric wages, even when the firms' underlying cost parameters are the same.…”