We propose a so-called trust matrix model to build trust for conducting first trade transactions in electronic commerce; i.e. transactions in an electronic commerce environment between two parties that have never conducted trade transactions between them before. The trust matrix model is based on the idea that for business-to-business electronic commerce a balance has to be found between anonymous procedural trust, i.e. procedural solutions for trust building, and personal trust based on positive past experiences within an existing business relation. Procedural trust building solutions are important for first trade situations, because of the lack of experience in these situations. The procedural trust solutions are related to the notion of institution-based trust, because the trust in the procedural solutions depends on the trust one has in the institutions that issued or enforces the procedure. The trust matrix model can be used as a tool to analyze and develop trust-building services to help organizations conduct first-trade electronic commerce transactions.