This paper empirically examines the relationship between the external business network of a country business unit (CBU) of a multinational firm, its performance, and the unique institutional characteristics of the foreign market in which it operates. We develop hypotheses about the CBU network structure associated with operating margin given different levels of institutional development, and the categories of network contacts associated with CBU operating margin. We test the hypotheses using social network analysis in 54 CBUs in two different business segments within one multinational company. Results show that the CBU network structure associated with higher operating margin depended partially on the level of the country's institutional development, and that network composition related strongly to CBU operating margin. We identify implications for research. Copyright © 2010 John Wiley & Sons, Ltd.