Measuring Economies of Vertical Integration in Network

This paper provides a framework that aims at distinguishing the technological economies of vertical integration from the vertical economies resulting from market imperfections. To illustrate our analyze, we use consistent panel data econometric methods to estimate cost functions on a sample of North-American water utilities. Contrary to what has been found for other network industries (electricity and gas for instance), we show that the economies of vertical integration are only significant for the smallest utilities