We study pricing by a monopoly platform that matches buyers and sellers in an environment with cross-market externalities. Said platform has no private information, does not set the commodity's price and can only charge trading parties for the transaction. Our innovation consists in introducing...

We study a dynamic contracting problem in which size is relevant. The agent may take on excessive risk to enhance short-term gains, which exposes the principal to large, infrequent losses. To preserve incentive compatibility, the optimal contract uses size as an instrument; there is downsizing...