Abstract
This paper investigates the effects of the National Industrial Recovery Act (NIRA) and the Robinson-Patman Act on market power in the 1930s rayon industry. Unlike the traditional structure-conduct-performance approach of constructing measures of market power from accounting data, the model we use in this paper estimates market power from a gauge of the discrepancy between price and marginal cost. The results show that the NIRA increased market power in the rayon industry, whereas the Robinson-Patman Act did not have a noticeable effect on market power. Also, market power appears to have steadily declined throughout the 1930s.