We study how the impact of capabilities for performance is contingent upon the environment. Using a novel dataset of information security start-ups, we study how markets for technology change the relative impact of technology and marketing capabilities on performance. Since internal technical effort enables firms to generate technology inputs instead of acquiring them from the market (substitute), a greater supply of technology diminishes the importance of technical ability as a source of competitive advantage. Moreover, since marketing capability complements technology inputs, a greater supply of technology enhances the impact of marketing capability on performance. Copyright © 2011 John Wiley & Sons, Ltd.