Agency Echelon
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A marketplace that connects buyers and sellers of programmatic inventory and runs the auction between them. Originally a distinct layer between SSPs and DSPs, exchanges have mostly merged into SSPs. Google's AdX, now part of Google Ad Manager, is the largest and the subject of the US Department of Justice's 2024 ad tech antitrust ruling, which found Google illegally monopolized publisher ad servers and ad exchanges.

Cite this entry: Agency Echelon. "Ad Exchange." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/ad-exchange/

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Reviewed September 23, 2026. Reference text is licensed CC BY 4.0. Privacy