The first methodology discussed is multi-agent architecture and this forms the basis of a simulation environment developed in order to test the proposed models. The second concerns a bargaining model based on the negotiation mechanism and the third centers on production planning to support agents during the bargaining phase. The fourth is the possibility of a coalition between the suppliers and the authors offer a choice of two different approaches. One is the application of Nash equilibrium to select the members of a potential coalition of sellers, while the other is a centralized approach with a profit sharing mechanism based on the Shapley value. All the innovative approaches reported in have been statistically tested in different market conditions. The methodologies, approaches and results presented in will be of interest to PhD students, operations managers and supply chain management researchers who develop value-added services for an e-marketplace in a business-to-business environment.