In aggregate, options on real and financial assets can have very different properties. Typically, the good or service produced by a real asset has a finite elasticity of demand and developers have finite capacities. Also, the supply of options can be limited, and developers can be less than perfectly competitive. In a subgame, perfect Nash equilibrium with these properties, the optimal exercise policy, and resulting values of developed and undeveloped assets are calculated explicitly. The novel comparative statics are discussed in details To date, options on real assets, like real estate, natural resources, and capital assets, have been analyzed only in partial equilibrium. 1 When viewed from the perspective of a single developer with a single undeveloped asset, real options have many characteristics in common with financial options. With real estate and other real assets, the option is an undeveloped property, the underlying asset is a developed property, the exercise price is the cost of development, and the maturity is generally infinite. In previous articles special characteristics of real options have been emphasized. These include the time to build, the often sto-I am grateful to Chester Spatt for suggesting this problem and to Chester