In the early models of incomplete contract neither party used to invest in the subject matter of the contract; those models primarily kept their focus on analyzing the effect of legal rules on parties' incentives to trade or to breach. The modern models stretched beyond that to include value...

A repeated moral hazard setting in which the Principal privately observes the Agent's output is studied. It is shown that there is no loss from restricting the analysis to contracts in which the Agent is supposed to exert effort every period, receives a constant efficiency wage and no feedback...