Vertical separation versus vertical integration in a macroeconomic model with imperfect competition

This paper develops a monopolistic competition macroeconomic model, and uses it to discuss the determination of relevant macro variables under both vertical separation and vertical integration regimes. Several main findings emerge from the analysis. First, in the market equilibrium aggregate output and consumption under the vertical integration regime are greater than under the vertical separation regime, while the product price index under the vertical integration regime is lower than that under the vertical separation regime. Secondly, the level of real aggregate profits under the vertical integration regime will be higher (lower) than that under the vertical separation regime if the degree of monopoly power is relatively large (small). Third, the welfare level under the vertical integration regime will be higher than that under the vertical separation regime regardless of the degree of monopoly power.