This thesis consists of four self-contained essays. The common theme of the essays is the behavior of multi-plant firms. An underlying idea in all four of them is that firms possess intangible assets such as management skills and organizational expertise, technological knowledge, marketing know-how and better access to finance capital or natural resources. These assets are typically specific to the respective firm. Due to market imperfections and failures, firms tend to internalize the advantages of firm-specific assets and exploit them themselves rather than sell or lease them to other firms. For instance, intangible assets are often joint inputs in the sense that knowledge developed by one unit can be transferred to another unit within the same firm at a low cost and without diminishing the amount of knowledge available to the first unit. Furthermore, the assets are typically only partly appropriable by their owner, and the market transactions of the assets are hampered due to information asymmetries between a potential buyer and seller. The literature on multinational firms emphasizes the role of intangible firm-specific assets in creating ownership advantages that, together with location and internalization advantages, explain the pattern of foreign direct investments. The essays in this thesis are based on the view that the ownership advantages created by firm-specific assets are the "raison d'etre" of large multi-plant firms. The existence of such assets is assumed to create multi-plant economies of scale and give incentives to make better use of capacity or overheads to gain advantage in size, economies of interdependent activities, integration and/or diversification. Rather than studying the international aspects of firms with intangible assets, the first three essays empirically explore different aspects of multi-plant firm behavior in domestic markets. This analysis has been made possible by the access to unique plant-level data on the thirty largest multinational manufacturing corporations in Sweden. The sample corporations play an important role in the Swedish economy. For instance, the thirty corporations account for about 70 percent of aggregate industrial R&D in 1999. This should be compared with their share of total manufacturing employment, which was about 30 percent during the period of study. The first essay examines the sources of productivity growth within multi-plant firms and particularly emphasizes the role of external restructuring and ownership changes in explaining why multi-plant firms may sustain higher productivity growth as compared to single-plant firms. The second and the third essay explore the idea that large multi-plant corporations exploit their ownership advantages when acquiring partial- and full-firm assets. The second essay analyzes whether technological intangible assets may explain transfers of productive capacity from acquiring corporations to their target. The third essay explores the idea that multi-plant corporations search for targets matching their firm-specific organizational capabilities when acquiring corporate assets. Uncertainty about the matching outcome explains why some acquisitions end in divestitures. However, the likelihood of a "good" match is expected to increase in the buyer's organizational capabilities. The fourth essay, coauthored with Karolina Ekholm, extends the analysis to encompass the international aspects of multinational firms. In this essay, we develop a theoretical model analyzing the localization decisions of multi-plant firms beyond the national borders. More specifically, we develop a two-country model where firms can choose to separate their innovative activities generating an intangible asset from the production of the final good. In our model, there are two agglomeration forces: knowledge spillovers associated with R&D and backward and forward linkages associated with high-tech production. We analyze how the interplay of these forces affects the localization decisions of the firms. / Diss. Stockholm : Handelshögsk., 2003