This article develops a typology that describes and measures different types of technological competence accumulation. The notion of accumulation comprises not only the state but also the change in competence, and hence it complies with the criticism of the static approaches to competence management. The typology of competence accumulation enables a comparison of firm profiles that lead to identification of four groups of firm behavior across the telecommunications industry. The relationship between the firm and the industry level is established on the condition that each firm's competence level depends on the firms' mutual relationships with other firms in the same industry (known as Red Queen evolution). The four groups of firm behaviour are therefore not considered as groups of independent firms that are similar by coincidence, but as patterns of behavior within the telecommunications industry, which allows for a discussion of more general implications for management of technology. Copyright 2005, Oxford University Press.