We consider a regulation problem with complete contracting in a principal-agent model with adverse selection and review within this model the various channels by which external competition parameters affect incentives within the regulated firm. The channels are: the principal's information, the principal's objective function, the agent's incentive constraint, the agent's participation constraint. We consider in particular a better information structure, a threat of liquidation, a fight for talent, a more efficient private sector, and the existence of better substitutes. We characterize in each case the conditions under which the effect on incentives is positive.