GroupM

Formerly the world's largest media investment group by spend under management; now operating as WPP Media, retaining its position as the dominant global media buying and planning operation within WPP.

GroupM was WPP's unified media investment and management operation, functioning as the parent company and resource hub for WPP's portfolio of media agencies. Founded in 2003, it served as the world's largest media buying and planning group, responsible for overseeing more than $60 billion in annual media spend on behalf of some of the world's largest advertisers. Its agency brands — Mindshare, Wavemaker, EssenceMediacom, and mSix&Partners — operated as distinct client-facing entities while benefiting from GroupM's centralized trading, data, and technology infrastructure. GroupM played a pivotal role in the AdTech ecosystem by operating at the intersection of media buying, data intelligence, and marketing technology. Through its data and technology unit Choreograph, its addressable TV offering Finecast, and its programmatic capabilities, GroupM provided advertisers with scaled access to media inventory alongside sophisticated audience targeting and measurement solutions. Its sheer scale gave it significant leverage in negotiations with media owners, platforms, and technology vendors globally. In Q2 2025, GroupM was rebranded as WPP Media as part of WPP CEO Cindy Rose's Elevate28 transformation strategy. The rebrand consolidated the group's identity more directly under the WPP parent brand while retaining the same operational structure, agency portfolio, and leadership. The agency brands — Mindshare, EssenceMediacom, Wavemaker, T&Pm, Choreograph, and Finecast — continue to operate under the new WPP Media umbrella, making GroupM a legacy name for what is now one of the most significant media investment operations in the world.