The Service Oriented Architecture (SOA) provides a methodology for designing software systems by integrating loosely coupled services. Compared to traditional distributed object-oriented architectures, SOA is more suitable to integrate heterogeneous systems, and more adaptable in a changing environment. This paper presents the design and implementation of a SOA framework for financial transaction applications. The framework provides an easy and uniform way for service composition in a controlled environment, and leverages Web service standards with efficient communication mechanisms and durable and/or transactional message queues. Speci?cally, the work addresses the following issues: 1) the incorporation of existing systems and protocols that are not Web-service compatible. This paper focuses on business processes of equities transactions using the FIX [6] protocol. 2) the congfiguration and deployment of services and service endpoints in a flexible and dynamic manner. 3) the capability of specifying business processes as Web service compositions and a distributed runtime environment that supports it. 4) the scalability, resiliency and transactional aspects as required in critical business applications. The experience of applying the framework in building a high performance equities transaction system is presented.