NONCLASSICAL DEMAND - A MODEL-FREE EXAMINATION OF PRICE-QUANTITY RELATIONS IN THE MARSEILLES FISH MARKET

We suggest a model for a market, the Marseille wholesale fish market, in which purchases do not correspond to standard competitive demand. W e use nonparametric methods to detect the properties of price-quantity relations which reveal 'strategic demand'. Our data over three months include price quantity details of each transaction for each fish, and the identities of the buyers and sellers. The observed distributions of prices are stable over time, thus the market can be treated as a re peated game. Strategic demand curves are obtained by local fitting. Th ey are downward-sloping at the aggregate level but not in general at t he individual level. Thus regularities are generated by aggregation ra ther than derived from individual behaviour.