Abstract: This paper focuses on the question of whether intra-group and inter-group rivalries have different performance impacts on firms partitioned by mobility barriers. The sample contains listed companies in the pharmaceutical industry of China over the period of 2010 to 2011. Data were mainly acquired from CSMAR and RESSET databases and annual reports of those companies. Grouping variables were selected according to strategic group research in pharmaceutical industry. The companies were clustered into four strategic groups aided by SAS software with Ward method, and then mobility barriers were identified.POLS and RE models were used to examine the effects of intra-group and inter-group rivalries in the panel data regressions, where the protection of mobility barriers is the moderating variable. Results show that intra-group rivalry has a stronger adverse impact on firms outside mobility barriers than on firms inside mobility barriers, whereas inter-group rivalry has a stronger adverse impact on firms inside mobility barriers than on firms outside mobility barriers. These findings indicate that rivalries within and between strategic groups have different influences on firm performance. Our findings also suggest that firm studies should take into consideration the strategic group structure and mobility barriers, and the effects of intra-group and inter-group rivalries should be analyzed separately rather than jointly.

Key words: strategic groups, mobility barriers, intra-group rivalry, inter-group rivalry, firm performance