The Federal Trade Commission, joined by a coalition of states, has launched a significant enforcement action aimed at alleged collusion among major advertising agencies in the digital advertising market. The April 15 announcement is notable not just for the parties involved, but for where regulators are focusing next: beyond dominant technology platforms and into the intermediary ad ecosystem that influences pricing, placement, and competition across online media.

That matters because advertising agencies sit at a critical junction between brands, publishers, platforms, and consumers.