Evaluating Traditional Share-Price and Residual Demand Measures of Market Power in the Catsup Industry

In this paper we specify a price determination model which can test both the traditional positive interbrand price share hypothesis and the negative intrabrand relationship predicted by residual demand analysis. We evaluate this relationship empirically using three-dimensional panel data from the catsup industry. We find support for both hypothesized relationships, and conclude that market power exists in this industry. Further, we conclude that the results depend critically on the characteristics of the data set to be analyzed.