Article dans une revue: We characterize the optimal dynamic contract for a long-term basic service when an uncertain add-on is required later on. Introducing firm risk aversion has two impacts. Profits for the basic service can be backloaded to induce cheaper information revelation for this service: an Income Effect which reduces output distortions. The firm must also bear some risk to induce information revelation for the add-on. This Risk Effect reduces the level of the add-on but hardens information revelation for the basic service. The interaction between these effects has important implications for the dynamics of distortions, contract renegotiation, and the value of incomplete contracts.