This paper investigates how leniency programs induce collusive offenders to self report in a dynamic setting, where the risk of independent detection evolves stochastically over time. We show how uncertainty about the future can push firms into preemptive application, and how these preemptive incentives can unravel to the point where firms apply long before the risk of detection is in any way imminent. For policy, the analysis suggests that a relatively harsh treatment of latecomers may be more important than offering high absolute reductions or even rewards, and that leniency should be available to firms who are already under investigation.