Advertising agencies covers the holding companies, network agencies, independent creative shops, media buying agencies and digital production studios sitting between brands and the channels they buy. The buyer is typically a CMO at a Fortune 1000 brand or a consumer-product founder with a media budget. Global ad spend ran around $1.1T in 2025 per GroupM, with digital now more than 70% of the pie and retail media and connected TV the fastest-growing lines. The category is structurally consolidating - the Omnicom-Interpublic merger announced in December 2024 created the largest holding group, while AI-native challengers and in-housing pressure the traditional agency model.

The sector spans creative agency networks, integrated media buying and planning, performance marketing and digital media, PR and earned media, brand experience and event marketing, production and content studios, retail media and commerce marketing, and the independent creative boutiques sitting outside the holding groups.

Revenue is led by retainer fees from anchor brand clients, project-based creative and production fees, media-buying commissions and trading margins, performance-based fees tied to campaign outcomes, and a growing line of technology, data and analytics fees as the holding groups push their proprietary platforms (WPP Open, Publicis Marcel, Omnicom Annalect) into the client mix.

Advertising agencies is part of IT services.