Enterprise computing is moving towards more open, collaborative systems. Joining a business network must be made efficient, despite the technical and semantic interoperability challenges involved in connecting different information and communication systems. Trust or lack thereof forms a pragmatic challenge: partners must continuously evaluate whether they trust each other enough to collaborate in the face of risk.??Supporting technology is needed for making trust-based decisions on routine business transactions and observing the business peers for malicious or incorrect behaviour on interactions.??We present a trust model for automating routine decision-making which considers both risk probabilities and tolerance valuations in the enterprise, and is dynamically updated based on new experience gathered both locally and from third parties.