Theories of inter-organisational co-ordination propose that information processing capabilities (structure, process and technology) must be aligned with information processing needs (environmental, partnership and task uncertainty) and the fit between both is a strong determinant of performance. Electronic marketplaces dominate new developments in electronic commerce. While traditional models predominantly deal with one-to-one relationships, electronic marketplaces are mainly characterized as being one-to-many and many-to-many in nature. Such developments have meant performance is based on more than just the fit between information processing needs and information processing capabilities. Consequently measuring performance has become much more difficult. From utilising current research the authors develop a theoretical model examining issues such as trust, investment and ownership.The paper details the development of the model and proposes a research strategy for testing it.