Forrester: 9 in 10 US agencies use AI, creativity at risk

Forrester and the 4A’s put a hard number on what agency leaders already feel in their margins: nine in 10 U.S. marketing agencies now use generative AI, and half are already using agentic AI for marketing execution. Released June 24, 2026, in Cannes and Cambridge, Massachusetts, the study says productivity and cost efficiency can come at the expense of creativity and marketing effectiveness.

That warning lands directly in SEO and digital agencies, where AI is already speeding up research, summaries, content drafts, and competitive analysis. Those are useful tasks, but they are also the easiest ones to commoditize. If an agency can only point to faster production, it is selling the same promise every other shop now makes. The stronger pitch is more specific: AI should shorten the path to better briefs, sharper editorial judgment, and work that still sounds like the brand the client hired the agency to protect.

Forrester’s latest numbers show how fast the market moved from curiosity to habit. In June 2024, more than 60% of agency decision-makers said their agency already used genAI, while 31% said they were still exploring use cases. Among large U.S. agencies with more than 201 employees, 78% were already using genAI. The 2026 figure, at nine in 10 agencies, makes clear that adoption is no longer the differentiator. Execution quality is.

The commercial model is where the pressure gets sharper. Forrester has said 75% of marketing agencies bear the costs of generative AI capabilities themselves rather than passing those costs to clients. That leaves agency operators in a familiar trap: absorb the software bill, pocket the efficiency gain, and hope the client never asks why the work now costs less to produce. Forrester’s warning is that opaque cost structures and services built around cheaper, faster output will not hold up for long if they strip out the strategic value clients actually buy.

The broader forecast is even less forgiving. Forrester says agencies will face an average 8% headcount cut in 2025 and another 15% reduction in jobs in 2026, while 85% of U.S. B2C marketing executives plan to review their media agencies this year. In a separate June 21 blog, Forrester said Google had become U.S. marketing agencies’ preferred AI partner, overtaking Adobe, Anthropic, Microsoft, and OpenAI. That mix of vendor consolidation, procurement pressure, and labor reduction leaves agencies with a narrow path: use AI to improve the work, not just the unit economics, or watch the market treat speed as table stakes.