To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.respol.2006.09.006 Byline: Anita M. McGahan (a), Brian S. Silverman (b) Keywords: Technological innovation; Competitor; Firm value Abstract: In 1986, Teece proposed a seminal framework for analyzing why innovators may fail to benefit from their innovations. He argued, in part, that firms with the requisite complementary assets can often expropriate an innovator's returns especially when appropriability regimes are weak. In this paper, we explore the implications of this framework from the perspective of an incumbent firm -- more precisely, of investors in that firm -- facing innovation by established corporate rivals and by inventors from outside its industry. We demonstrate that the financial-market value of publicly traded firms depends on patented innovation by competitors (both established rivals and industry outsiders). Our empirical study generates three main results. First, the financial-market value of an incumbent is negatively associated with 'important' patenting by outside inventors. Second, in industries characterized by weak appropriability regimes or by a strong reliance on complementary assets, this relationship is reversed: important patenting by outsiders is positively associated with the incumbent's financial-market value. Third, the effect of outsiders' patented innovation on the focal incumbent is qualitatively different than that of established rivals' patented innovation on the incumbent. These results are consistent with implications of Teece [Teece, D., 1986. Profiting from Innovation, Research Policy] and with recently developed models that formalize elements of his framework. More generally, these results support theories about both the market-stealing and spillover effects of innovation. Author Affiliation: (a) Everett W. Lord Distinguished Faculty Scholar, Strategy and Policy, Boston University, 595 Commonwealth Avenue, Boston, MA 02215, United States (b) J.R.S. Prichard and Ann Wilson Chair in Mgmt, Rotman School of Management, University of Toronto, 105 St. George Street, Toronto, Ont. M5S 3E6, Canada