Business & finance · also called holdco, agency holding company
Holding company (agency holdco)
An agency holding company (holdco) is a parent group that owns many advertising, media, creative and marketing agencies, such as WPP, Publicis Groupe, Omnicom, Dentsu and Havas.
Holdcos are the conglomerates of advertising. Each owns dozens of agency brands (media agencies, creative shops, PR firms, data and technology units) and pools their scale to negotiate with media owners and platforms. The largest global groups are WPP, Publicis Groupe, Omnicom, Dentsu and Havas. Omnicom became even larger after completing its acquisition of IPG (Interpublic Group) in late 2025.
Holdcos matter to ad tech because they direct a huge share of large advertisers' media budgets. They run programmatic trading desks, negotiate deals with DSPs and SSPs, build data and identity assets (for example Publicis's Epsilon and Omnicom's Acxiom, which came with IPG), and increasingly engage in principal-based buying.
Their business model is under pressure from in-housing, consultancies, walled gardens' self-serve tools and AI automation. Transparency questions, including media rebates and principal media margins, remain a long-running tension with advertisers and bodies such as the ANA.
Think of it like this
An agency holdco is like a restaurant group that owns many different restaurants under different names, sharing one central kitchen and one big buying power with suppliers.
An example
A global consumer goods company consolidates its US$1 billion media account at one holdco, which splits the work among its media agency, creative agencies and data unit.
Related terms
Agency
An agency is a company that plans, buys, creates or manages advertising on behalf of advertisers, in exchange for fees, commissions or a margin on the media it buys.
Trading desk
A trading desk is a specialist team, usually inside an agency or advertiser, that plans and executes programmatic buying on DSPs on behalf of campaigns and clients.
Principal-based buying
Principal-based buying is when an agency buys media for its own account and resells it to clients at a price it sets, instead of buying at cost as the client's agent.
Media rebates
Media rebates are payments, credits or free inventory media owners give agencies for the volume of client spend they bring, which may or may not reach advertisers.
Advertiser
An advertiser is the company, organisation or person that pays to place ads in order to sell products, build a brand, recruit, or spread a message.