Sole sourcing may be the result of a monopoly, where only one supplier exists capable of satisfying a requirement. Situations involving a monopoly must be fed back into the purchase planning process so that the Postal Service can take steps to either widen the requirement or stimulate competitive suppliers in the future. Sole sourcing may also be imposed by the client’s insistence on a specific source for a material or service or as a requirement of other stakeholders. In either case, the purchase/SCM team must ensure that those making the requirement are cognizant of the future risks of sole sourcing. Such risks may include greater vulnerability to rising prices and greater exposure to interrupted supply continuity.