Agricultural economics society prize essay - Imperfect price transmission: Is market power really to blame?

Several studies in the literature have argued that price transmission in vertically-related markets is imperfect, i.e. that farm input price changes are not fully passed-through to the final product price. Market power, notably oligopoly, is presumed to be the principal source of imperfect price transmission. To date, the impact of oligopsony (buyer) power oil the degree of price transmission has not been evaluated using a formal theoretical model. Moreover, neither has the combination of oligopoly and oligopsony despite the fact that its influence has been formally acknowledged in both the UK and some European food markets. This paper makes a contribution to the literature by developing a model of price transmission where both oligopoly and oligopsony power co-exist and where industry technology is assumed to be characterised by variable input proportions. It shows that taking the degree of price transmission in a perfectly competitive market as a benchmark, oligopoly and oligopsony power do not necessarily lead to imperfect price transmission, although they can. Indeed, they may counteract each other's impact on the degree of price transmission. The key to these outcomes is to be found in the functional forms for retail demand and farm supply.