What is an outside vendor who has the authority to buy products and services from others called?

The correct term for an outside vendor who has the authority to buy products and services from others is a purchasing officer. This individual is responsible for making procurement decisions and managing purchasing agreements with suppliers. The role typically involves assessing the needs of the organization, negotiating terms, and ensuring that purchases align with budgetary constraints and company policies.

A systems integrator is typically focused on combining different subsystems into a whole and ensuring they function together, which is different from directly purchasing products and services. A sales agent usually represents a company in selling its products or services rather than making purchasing decisions. A supply chain manager oversees the entire supply chain process, from procurement to delivery, but does not specifically denote a role focused only on direct purchasing authority.

Given this understanding, the correct answer aligns with the specific authority and functions of a purchasing officer, who directly engages in the buying process.