Ad exchange

An ad exchange is a technology platform that facilitates the buying and selling of media advertising inventory from multiple ad networks. Prices for the inventory are determined through real-time bidding (RTB). The approach is technology-driven as opposed to the historical approach of negotiating price on media inventory. This represents a field beyond ad networks as defined by the Interactive Advertising Bureau (IAB), and by advertising trade publications.

Ad exchanges
Notable ad exchanges include:
 * AppLovin (which recently acquired MoPub)
 * FreeWheel (owned by Comcast)
 * Google Ad Manager (also known as Google Authorized Buyers, formerly known as AdX, and now part of Google Ad Manager)
 * InMobi
 * Magnite Inc (formed by the combination of Rubicon Project, SpotX, and Telaria)
 * OpenX (company)
 * Pubmatic
 * Smaato
 * Xandr (formerly AT&T AdWorks which bought AppNexus, now owned by Microsoft)
 * Yahoo (formerly AOL, Brightroll, OATH and other entities rolled into the Yahoo brand)