Measuring Oligopsony Power of UK Salmon Retailers

A significant increase of concentration in the UK salmon retail subsector has heightened concerns about retail firms' ability to exercise market power in the purchase of supplies (oligopsony power). To assess the extent to which retail firms have exercised oligopsony power, we develop a dynamic error correction translog profit Junction to model the behaviour of retailers in the input market for smoke, fillet, and whole salmon. Initial estimates indicated violations of monotonicity and convexity conditions as implied by economic theory. fit order to ameliorate the problem, a Bayesian technique was used to impose inequality restrictions to correct the anomaly. The final estimated indices of market power ill the models were low and statistically significant but sufficiently closer to the perfect competition benchmark indicating that retailers as a whole behaved competitively during much of the period covered by this study.