The ad market in Europe and Belgium, and three scenarios for agents to 2029
European digital advertising grew 10.5% in 2025 and Belgian media keep 79% of media investment. Nobody can yet measure how much will be bought by agents, so we work with three scenarios.
Before deciding how much to invest in agents, it helps to look at the market they will operate in. This article summarises the latest European and Belgian figures and explains why we prefer scenarios to forecasts when it comes to agentic advertising.
Europe: still growing, driven by video, social and retail media
According to IAB Europe’s AdEx Benchmark 2025, published in July 2026, digital advertising in Europe reached €131.1 billion in 2025, up 10.5% on 2024. Every one of the 30 markets tracked grew.
- €131.1 bn European digital ad spend in 2025 (+10.5%)
- €34.0 bn video (+19.6%)
- €35.5 bn social (+19.2%)
- €13.3 bn retail media (+16.7%)
Search remains the largest category at €56.2 billion (+8.8%), while non-video display was flat. Retail media passed 10% of digital spend for the first time. For publishers, the message is clear: growth is in video and in formats tied to data, while standard display has stopped growing.
A market this large and this fragmented, with dozens of countries, languages and sellers, is exactly where shared interfaces for agents make sense. A buying agent that has to learn every publisher’s rate card by hand gains little.
Belgium: local media remain strong
The UMA/UBA Benchmark Media Investments 2025 shows a market where Belgian media keep a strong position:
- 79% of media investment goes to Belgian media
- 37.4% digital share of the total
- ~80% local share in the digital channels where local and international players really compete
Those competitive channels are online video, display and other digital formats. Search and social are left out because there is no Belgian search engine or national social network to compare with. In other words, the international platforms dominate search and social, but display and video are where Belgian publishers compete directly, and where they win most of the budget.
One caution on comparisons: the 2025 benchmark uses a much wider scope than earlier editions, including direct sales by local media. The previous edition put digital at 41.9% of the 2024 total; the new, more complete scope puts it at 37.4%. The two figures cannot be compared as a trend.
The demand side is moving
In the United States, IAB’s 2026 Outlook expects ad spend to grow 9.5% in 2026, and about two-thirds of the buyers surveyed said they plan to focus more on agentic AI for buying and campaign execution. That is a US result and should not be applied mechanically to Belgium, but it is an early signal of what buyers will ask for.
Why scenarios rather than a forecast
There is no reliable statistical series yet that would let anyone predict the share of advertising bought by agents in Belgium in 2029. Ad spend forecasts exist; agentic adoption forecasts would be guesses. We therefore plan with three scenarios:
| Scenario | 2027 | 2028 | 2029 |
|---|---|---|---|
| Conservative | Copilots dominate; agents are mostly read-only. | Controlled actions in a few workflows. | Agent-to-agent buying is still niche; people remain at the centre. |
| Central | Monitoring and reporting agents are common. | Sales and ad-ops agents are connected to tools; catalogues are structured. | Agent-to-agent is used for part of direct and programmatic workflows. |
| Accelerated | Buying agents, MCP and A2A accelerate. | Catalogues and APIs become a commercial advantage. | Planning, proposals, deals and reporting are largely machine-to-machine, under policies. |
The point is not to pick one. The first investments, in data, a product catalogue and an advertising API, pay off in all three. What changes between scenarios is how fast you open those foundations to external agents.
Signals to watch
- Adoption of buyer and seller agents, and growth of IAB Tech Lab’s Agent Registry.
- APIs and MCP servers from DSPs, SSPs, ad servers, data providers and measurement vendors.
- Real use of agents by agencies and advertisers, not just product announcements.
- Identity, delegated authority, contracts and payments designed for agents.
- Traffic from assistants and agents to publishers’ own sites.
- EU regulation and audit practices, starting with the AI Act’s transparency rules.
We will come back to these signals as the standards and the market evolve.
Sources
- IAB Europe: retail media gains 16.7% as video grows, PPC Land, July 2026, on the IAB Europe AdEx Benchmark 2025.
- UMA/UBA Benchmark Media Investments 2025: 79% of advertising spend goes to local media, UMA.
- Digital advertising surges to 41.9% of media investment, UBA, March 2025.
- 2026 Outlook, IAB, January 2026.