Predator control cost-share contracts among livestock producers to control coyote predation date back to 1630 in North America and are common today among sheep producers in western states. Typically, per unit assessments are imposed on a monitorable input, and revenues are used to purchase predator control for participants' land. This study presents a model which provides refutable implications for the structure and distribution of these contracts over time and space. Historical and contemporary state and county data on sheep producer assessments support a model that is applicable more generally to the problem of investment in common property inputs.