We explore the technological evolution of three microprocessor firms between 1976 and 2004. We trace how two initially small entrants (Intel and AMD) competed against a larger and more established incumbent (IBM). We show that changes in interfirm relationships (as reflected by competitive and cooperative events) affect patenting strategies. Periods of increased competition correspond to greater patenting within patent classes in which the firms compete head-on. Periods of cooperation are surprisingly not always accompanied by increased patenting in complementary upstream and downstream areas. Despite changes in competitive regime, Intel and AMD exhibit a persistent dependence upon IBM for technology. Our study shows that small firms can compete against a large incumbent in the product market while being dependent upon external sources for knowledge. We also suggest ways in which incumbent firms operating in such environments (e.g., IBM) might engage with these entrants through co-opetition and open innovation.
Keywords: open innovation, IBM, Intel, AMD, patents, semiconductor industry, co-opetition