In the SIAM structure that uses a lead supplier as the service integrator, who has the contractual relationship with the external service providers?

In the 'lead supplier as service integrator' model, the customer organization selects an existing, often strategic, supplier to perform the service integration function in addition to their primary service delivery role. A key characteristic of this model is that the customer organization typically retains direct contractual relationships with all service providers, including the lead supplier and other external providers. The lead supplier then manages and coordinates these providers on behalf of the customer, but the legal and financial agreements remain between the customer and each individual provider. This structure allows the customer to maintain control and avoid vendor lock-in.

B. lead supplier: This is incorrect. In this specific SIAM model, the lead supplier manages the other providers but does not typically hold the contractual relationship with them; the customer does.
C. prime vendor: This describes a different sourcing model where a prime vendor holds a single contract with the customer and then subcontracts to other providers, which is not the 'lead supplier' SIAM model.
D. service integrator: This is the role the lead supplier performs. As explained for option B, the service integrator in this model manages, but does not contract with, the other providers.

1. Scopism. (2020). Service Integration and Management (SIAM™) Foundation Body of Knowledge (BoK) (Second Edition). Section 4.4.4, 'Lead supplier as service integrator', Page 61. "In this model, the customer organization has a contract with the lead supplier for the services it provides, and for the service integration capability. The customer organization also has contracts with the other service providers."

2. Scopism. (2020). Service Integration and Management (SIAM™) Professional Body of Knowledge (BoK) (Second Edition). Section 3.2.4, 'Lead Supplier Integrator', Page 35. "The customer retains contracts with all the service providers, including the lead supplier."