The forest product companies’ ownership of timberland is decreasing in the United States as in many other countries. In aggregate the forest product industry owned 26.5 million hectares (11.6% of the U.S. timberland) in 2002 compared with 28.5 million hectares in 1987 (FIA 2006). Reasons for this decrease of timberland ownership are several and complex. This article presents four case studies of U.S.-based forest product companies. The vertical integration theory and empirical studies about timberland ownership give a base for the study. Four hypotheses are formulated on the basis of the literature. The results give support to two of them. An important reason for timberland ownership is a wish to secure deliveries. Market conditions are important for the need of owning timberland. Two of the companies did not own timberland, the main reason being more profitable alternative uses of capital. The ownership structure of the company, tradition, and culture are other important explanations for timberland ownership. This study did not show the advantage of timberland ownership for information and coordination.