A company's suppliers and the suppliers' suppliers are considered the portion of the supply chain.

Upstream portion

Explanation:

Supply chain is defined as the network of all resources, individuals, activities, technology and organization, who are engage in the establishment of the product and sale of the product, from delivery of materials to the manufacturer.

Suppliers of the company and the suppliers who supplies are considered to be the upstream portion of the supply chain. It is that portion of supply chain which involves the supplies of the company and the processes who manages the relationship with them.

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