Conducting business on the Internet poses many risks and involves making trusting decisions. Software agents re?ecting the preferences of their users will have different trust attitudes and can therefore make different trusting choices. We present the results of a simulation for a market scenario in which buyers and sellers are not always fully committed to the market?s protocol. Our interest is in the effects of different trust attitudes (trust dispositions and risk behaviours) on the monetary gains of the individual agents and the electronic market as a whole.