In particular, outsourcing is the practice of involving the third party to create supply chain surplus. It includes aggregate planning in capacity, inventory, transportation, warehousing, procurement, information, relationship and costs. All these units integrate to produce the supply chain surplus when outsourcing is in place.
Not all these functions are outsourced depending on an organization to outsource which of their facility. Inditex, having said that, owns 40% of manufacturing while the rest is outsourced such as, capacity, procurement and costs (Chopra, Meindl 3rd Ed).