Madison & Wall projects that AI-directed campaign products will manage 27% of U.S. ad spending by 2030, roughly $158 billion, up from 12% today and just 2% in 2023. The research consultancy’s managing director Luke Stillman has been quietly rewriting the industry’s growth curve inside an addressable 2026 U.S. market worth $479 billion excluding political spend, and the shape of that curve is no longer really about total dollars. It’s about who directs them.

The migration is already visible at the platform level. Around 30% of Google’s search spend now runs through AI Max or Performance Max, and Meta CFO Susan Li has said Advantage+ is on a $75 billion run rate this year, up from $60 billion in 2025. Reddit, Pinterest, and TikTok have shipped their own automated equivalents.

Agencies are further along than the top-line numbers suggest. Tinuiti has tracked Performance Max at 60%–70% of ad spend among retail clients since Q4 2025. At Ars X Machina, Scott Hendler puts PMax at “well over 50%” of client budgets. Roast’s Becca Shih pegs her agency at 11%–12%. Jellyfish’s John Dawson dismisses the idea of a 20%–30% automation ceiling, saying media automation will reach 90%.

The concentration story runs alongside it. Google, Meta, and Amazon collectively took 56% of U.S. ad revenue in 2025, up from 53% in 2024, with Google rising from 28% to 29%, Meta from 17% to 19%, and Amazon from 8% to 9%. Everyone else shrank from 47% to 43%. IAB CEO David Cohen’s group has revised 2026 U.S. ad growth to 12.3% from 9.5%, led by social at 16.5%, CTV at 15.6%, and commerce media at 13.6%.

Madison & Wall then sees growth cooling to 7% in 2027 and 5% by 2029. The AI layer isn’t disrupting the walled gardens. It’s paving them.

Sources