This paper can be downloaded without charge at: The Fondazione Eni Enrico Mattei Note di Lavoro Series Index: http://www.feem.it/Feem/Pub/Publications/WPapers/default.htm Social Science Research Network Electronic Paper Collection: http://ssrn.com/abstract=XXXXXX The opinions expressed in this paper do not necessarily reflect the position of Fondazione Eni Enrico Mattei Merger Performance under Uncertain Efficiency Gains Rabah Amir, Effrosyni Diamantoudi and Licun Xue NOTA DI LAVORO 79.2004 MAY 2004 CTN – Coalition Theory Network Rabah Amir, CORE and Department of Economics, UCL Effrosyni Diamantoudi, Department of Economics, University of Aarhus Licun Xue, Department of Economics, University of Aarhus