Programmatic agencies.

Only eleven UK agencies in the index lead with programmatic, and that number reflects how the discipline actually sits in the market. The big trading volumes live inside holding-group network agencies (GroupM, Publicis, Omnicom, Dentsu, Havas, IPG) and a small set of independent trading desks. Below the network tier, most generalist digital agencies treat programmatic as a sub-line of paid media, executed via DV360 or The Trade Desk rather than as a headline service. When a media plan is genuinely programmatic-led, the credible shortlist is short. Pricing in 2026 has two visible layers and one that often isn't. The visible layers are agency management fee (retainer, percentage of spend, or hybrid) and DSP access fee, typically 10-20% of media passed through or bundled. The invisible layer is the wider supply chain: SSP take, data licensing, verification, curation, and reseller hops. ISBA's Programmatic Supply Chain Transparency work and the 2024 ANA benchmark both found that less than half of every pound entering a DSP reaches a working publisher. The practical lesson is to demand log-level data and a separated fee schedule, not an all-in CPM. The same procurement conversation now also covers cookieless planning, supply path optimisation, Made-for-Advertising exclusion, and emissions-aware buying via Scope3.