We analyze the impact of partial public ownership (PPO) on managerial incentives. A novelty of the paper is that it explicitly considers competition in the product market. We find that PPO negatively affects managerial incentives when all firms are partially owned by the government. When partially public firms compete with private firms, the effects on managerial incentives crucially depend on the degree of competitive pressure. Thereby, PPO induces either partially public firms or their private competitors to offer stronger managerial incentives. This result is essentially confirmed even if the government's primary concern is consumer protection rather than social welfare.