We analyse a stylized model of the world grain market characterized by a small oligopoly of traders with market power on both the supply and demand side. Crops are stochastic and exporting countries can impose export tariffs to protect domestic food prices. Our first result is that export...

We study contracting between a consumer and an expert. The expert can invest in diagnosis to obtain a noisy signal about whether a low-cost service is sufficient or whether a high-cost treatment is required to solve the consumerś problem. This involves moral hazard because diagnosis effort and...