We develop and implement a model for a profit maximizing firm that provides an intermediation service between commodity producers and commodity end-users distributed over a realistic spatial network. Producers and end-users trade with the firm through contracts for delivery of grain during the marketing season. The firm begins the marketing season with a portfolio of prearranged purchase and sa...

This paper reports on a two-task principal-agent experiment in which only one task is contractible. The principal can either offer a piece-rate contract or a (voluntary) bonus to the agent. Bonus contracts strongly outperform piece rate contracts. Many principals reward high efforts on both tasks with substantial bonuses. Agents anticipate this and provide high efforts on both tasks. In contras...

This paper reports on a two-task principal-agent experiment in which only one task is contractible. The principal can either offer a piece-rate contract or a (voluntary) bonus to the agent. Bonus contracts strongly outperform piece rate contracts. Many principals reward high efforts on both tasks with substantial bonuses. Agents anticipate this and provide high efforts on both tasks. In contras...