Reference / Glossary / Practice and industry
Principal-Based Buying
Also: Inventory media; Proprietary media
An arrangement in which the agency buys media on its own account and resells it to the client at a price of its choosing, acting as principal rather than agent, so the margin is not disclosed. Principal-based buying is legal with client consent and is now a major profit source for holding companies; the ANA has repeatedly urged advertisers to require disclosure and opt-in.
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Cite this entry:
Agency Echelon. "Principal-Based Buying." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/principal-based-buying/