The changes that took place in the telecommunications equipment industry during the 1990s can be attributed to both the introduction of new technologies and regulations and to the dynamics of demand and the industry. These changes led to many types of collaborative arrangements between firms ranging from contractual agreements and joint ventures to mergers and acquisitions. Based on 947 arrangements made by the 21 leading equipment manufacturers from 1992-1999, we examine the dynamics of governance structures. Moreover, we demonstrate that while the beginning of the period is characterized by very open contractual agreements, a trend towards mergers and acquisitions developed later on. In less than ten years, the cooperative strategies of the main equipment manufacturers underwent major changes in their form of governance. These dramatic changes may be explained by the dynamics of demand and technologies in different sectors of the market.