Int. Rev. Econ. (2007) 54:261–283 DOI 10.1007/s12232-007-0017-2 DEREGULATION, CONSOLIDATION AND BANKS EFFICIENCY IN SINGAPORE: EVIDENCE FROM EVENT STUDY WINDOW APPROACH AND TOBIT ANALYSIS FADZLAN SUFIAN  and MUHAMED-ZULKHIBRI ABDUL MAJID  Abstract: A three-year window analysis together with the Data Envelopment Analysis (DEA) approach is employed to investigate the effects of mergers and acquisitions on the Singapore banking groups’ efficiency. The results suggest that the merger has resulted in a higher Singapore banking groups’ mean overall efficiency. We do not find evidence of more efficient acquirers compared to the targets and that the acquiring banks’ mean overall efficiency tends to improve from the merger with a more efficient bank. The Tobit regression results suggest that bank profitability has positive impact on bank efficiency, whereas poor loan quality has negative influence on bank performance. (JEL: G21, D24) Keywords: bank mergers, Data Envelopment Analysis, Singapore, Tobit model 1. Introduction Examining banking performance has been a common practice among banking and finance researchers for a number of years. The main reason for  Planning and Research Department (BCB), Bumiputra-Commerce Bank Berhad and Department of Banking and Finance, University of Malaya, Kuala Lumpur (Malaysia). E-mail: fadzlan.sufian@cimb.com  Central Bank of Malaysia and Monetary and Financial Policy Department, Bank Negara Malaysia, Kuala Lumpur (Malaysia). E-mail: muhamedz@bnm.gov.my All findings, interpretations, and conclusions are solely those of the authors’ and do not necessarily represent the views of the institutions to which they belong. We would like to thank the anonymous referees for their comments and suggestions. The remaining errors are of our own. © Springer-Verlag 2007 123