This article addresses two questions. Firstly, which incentive structure is needed if we are to see the emergence of electronic markets and, secondly, which implications follow from this for the idea of open electronic markets. It is proposed to adopt a rather narrow concept of electronic markets which strongly relies on the notion of a competitive price mechanism in order to identify those pre-conditions which are specific to electronic markets as compared to other interorganisational systems. It is concluded that the applicability of this new coordination mechanism is resricted to groups establishing organised markets on the basis of strictly monitored membership rules which implies that there are only imperfectly competitive markets for electronic markets.