{IT-based} Service Economy requires Service Markets to flourish for the trade of services. market does not represent a simple buyer-seller relationship, rather it is the culmination point of a complex chain of stake-holders with a hierarchical integration of value along each point in the chain. To enable a Service Economy, Service Markets must be practically realized, which in turn requires an enabling infrastructure to support service value chains and service choreographies resulting from service composition scenarios. In such scenarios, services compose together hierarchically in a producer{\textendash}consumer manner to form service supply-chains of added value. Service Level Agreements {(SLAs)} are defined at various levels in this hierarchy to ensure the expected quality of service for different stakeholders. Automation of service composition directly implies the aggregation of their corresponding {SLAs.} In this paperwe elaborate on the requirements of hierarchical aggregation of {SLAs} corresponding to service choreographies leading to businessmodels such as Business Value Networks. During the hierarchical aggregation of {SLAs,} certain {SLA} information pertaining to different stakeholders is meant to be restricted and can be only partially revealed to a subset of their business {partners.We} introduce the concept of {SLA-Views} to protect such privacy concerns. We then formalize the notion of {SLA} Choreography and define an aggregation model based on {SLA-Views} to enable the automation of hierarchical aggregation of Service Level Agreements. The aggregation model has been designed to comply with {theWS-Agreement} standard.