Effects of vertical integration on price and volume: An empirical inquiry

A simple model with two stages of production is used for deriving some empirically testable hypotheses. Firms (two upstream and two downstream) in the industry are either vertically integrated or not, hence the industry has three alternative patterns: Complete unintegrated, partially integrated, or fully integrated.Final good prices, outputs and profits of firms are different in each integration pattern but what is optimal can not be stated (i.e., pay-offs are much too complicated in order to solve the sub-game equilibrium).The essential feature of the model is that there are external markets for the intermediate inputs. Hence input trade between the four firms/divisions need not balance since excess supply or demand is traded at the external market. With this feature purely downstream exogenous shocks have no effect on upstream pricing nor production decisions if all four firms are unintegrated. Such exogenous shocks have non-zero effects if at least one firm is vertically integrated. There are also other dissimilarities in comparative statics of each industry integration pattern.An indirect method to test the effects of vertical integration on price and volume is presented and empirically tested. Depending on the vertical integration pattern of an industry exogenous shocks have dissimilar effects on prices and outputs of the final and intermediate good. A four equations system is estimated by using Finnish forest industry firm data. Final good demand rise has a reducing effect on both paper and pulp prices. Stumpage prices (upstream marginal costs) have a negative impact on paper and pulp production and a positive impact on prices. These effects from upstream (downstream) stage into downstream (upstream) market should not occur when all firms are unintegrated.This is a revised version of a paper which was presented at seminars at Brussels, Turku, Vienna, and Stuttgart. I would like to thank seminar participants (specially Frank Schmid) and anonymous referees for helpful comments. Financial support from the Marcus Wallenberg Foundation is gratefully acknowledged.