Modelling upstream and downstream market power in bilateral oligopoly

This article develops a general model that estimates market power exertion in a bilateral market relationship for processors and retailers where each may also have market power in their primary input market and output markets, respectively. Monte Carlo experiments are used to generate industry data for market structures such as perfect competition, monopoly, monopsony, bilateral imperfect competition with an integrated processor/retailer, bilateral imperfect competition with separate processor and retailer, and bilateral imperfect competition with four adjacent upstream and downstream markets. Then, new empirical industrial organization models are estimated using the data with models that match the market structure under which the data were generated (true) and with models that reflect alternative market structures (alternative). The general model is derived using the production function approach without imposing the fixed proportion assumption. Monte Carlo simulation results indicate that the general model is preferred to alternative models that presume competitive behaviour by processors in primary input procurement and by retailers in the output market. Results indicate that less flexible models lead to biased market power estimates in the presence of market power in the corresponding input and output markets.