Regulatory decisions about search usually get filed as publisher stories. This one is a layout story, and layout decides whether an ad gets seen.
On 3 June 2026 the Competition and Markets Authority imposed a conduct requirement on Google Search under the UK’s digital markets regime. The headline provision hasn’t been done anywhere else in the world.
What Was Imposed
The requirement follows the CMA designating Google with strategic market status in general search, which gave the regulator power to impose targeted rules where it considers them proportionate.
Publishers now have effective tools to prevent their content being used to power AI features including AI Overviews. Google also has to attribute publisher content with clear links inside AI-generated results and, after consultation feedback, let publishers opt out of having their content used to fine-tune AI models.
Sarah Cardell, the CMA’s chief executive, framed it around AI Overviews reshaping search and publishers needing real bargaining power over how their content gets used.
Google has nine months to implement, though the CMA expects the important parts to reach publishers well before that. Compliance reports are due every six months for the first year.
Why This Changes Page Composition
Here’s the bit that’s gone underdiscussed. If a meaningful number of publishers use the opt-out, AI Overviews have less material to draw on for the queries those publishers covered.
An AI summary is only as complete as its sources. Take away enough sources for a given topic and either the summary gets thinner or it stops appearing for that query.
Both outcomes push organic results and ad units back up the page.
Vertical position has been the quiet casualty of the AI Overview era. The ad unit itself didn’t change. What changed is how much screen sits above it. A Google Vehicle Ads unit in the same nominal position on a page carrying a tall AI summary is a materially different asset from the same unit on a page without one, and advertising that depends on being seen before a decision forms depends on exactly this.
Uptake Will Be Wildly Uneven
Forecasting this is genuinely hard because opt-out behaviour will vary enormously by sector.
News publishers have the strongest incentive and the best organisation. Documented traffic losses, active legal complaints, trade bodies that have been talking to the CMA throughout. Expect real uptake there.
Commercial and transactional content is a different sum entirely. A site whose model depends on being cited may well decide visibility inside AI features beats the traffic it displaces.
So there won’t be a uniform retreat of AI Overviews. There’ll be a patchwork, with some query categories thinning out considerably and others not moving at all. Sectors sitting between editorial and commercial content are hardest to call, and vehicle search sits awkwardly in that gap, pulling on review content, market commentary and listings all at once.
What the CMA Has Signalled Next
The regulator has been explicit that this is one measure in a sequence.
Google announced significant changes to embed AI further into search in May 2026, and the CMA has confirmed the conduct requirement covers those changes. It’s monitoring implementation and has said it’ll bring forward further measures if the exchange of value between Google and publishers stays unfair. It has also flagged more action on Google’s search business in the following weeks, and has four strategic market status investigations running across Google, Apple and Microsoft.
Buried in the CMA’s language is a point worth taking seriously. The regulator keeps emphasising the flexibility of the UK regime, its ability to respond to what a designated firm is doing now and in future.
For anyone whose advertising performance depends on how a Google results page gets assembled, that flexibility cuts both ways. The composition of that page is now subject to ongoing regulatory adjustment instead of being purely a product decision.
Campaigns built on assumptions about where a unit sits vertically are, for the first time, built on something a UK regulator is actively reshaping. Which argues for measuring visibility directly instead of inferring it from position data that no longer means what it used to.