Arrangements by which politically connected firms receive economic favors are a common feature around the world, but little is known of the form or effects of influence in business-government relationships. We argue that influence not only brings significant privileges for selected firms, but requires firms to relinquish certain control rights in exchange for subsidies and protection. We show that, under these conditions, political influence can actually harm firm performance. Enterprise surveys from approximately 8,000 firms in 40 developing countries indicate that influential firms benefit from lower administrative and regulatory barriers (including bribe taxes), greater pricing power, and easier access to credit. But these firms also provide politically valuable benefits to incumbents through bloated payrolls and greater tax payments. These firms are also less likely to invest and innovate, and suffer from lower productivity than their non-influential counterparts. Our results highlight a potential channel by which cronyism leads to persistent underdevelopment.