AI Will Run 80% of US Ad Spend by 2028 — Here's How to Keep Control
Gartner expects 80% of US ad spend to flow through AI-powered platforms by 2028 — so the marketer's job shifts from running campaigns to supervising machines that profit when you spend more, which makes independent measurement the new core skill.
The number: 80% of US ad spend, AI-run, by 2028
By 2028, some 80% of US ad spending will flow through AI-powered platforms, according to Gartner analyst Eric Schmitt. Globally, Gartner expects more than 70% of ad spend to move through self-serve systems where AI 'materially influences' the outcome. Media buying, in other words, is becoming something you supervise rather than something you do.
Schmitt's warning is blunt: 'One has to be very cautious right now about turning over too much autonomy to these systems.' The tools — Google's Performance Max, Meta's Advantage+, Amazon's suite — promise efficiency. The risk is that efficiency gets measured on the platform's terms, not yours.
'Machine bias': the platforms optimise for themselves
The core problem is a conflict of interest baked into the machine. As Schmitt puts it, the AI's recommendation almost always amounts to 'you should spend more with us'. These systems are built to maximise the platform's revenue, which is not the same objective as minimising your cost per acquisition.
That matters more as concentration rises: Google, Meta and Amazon already command roughly 60% of global ad spend. Hand an opaque, self-interested optimiser a bigger share of budget with fewer guardrails, and you are trusting the referee to also keep score.
The Marketing Minute playbook for keeping control
The answer is not to boycott AI buying — that ship has sailed — but to supervise it like any powerful contractor. First, keep a human on the budget: no unfettered spend authority without review. Second, define the business outcome before you switch a tool on, so the machine optimises to your goal rather than its own proxy.
Third, limit the variables: fewer platforms and cleaner objectives make it far easier to see what is actually working. Fourth — and most important — measure independently. Do not accept platform self-reporting as truth; use third-party or incrementality measurement, and bring finance into the room to pressure-test the numbers.
The bottom line for CMOs and CFOs
The uncomfortable shift is cultural, not technical. As AI absorbs the mechanics of buying, the marketer's job moves from pulling levers to setting objectives, auditing outputs and owning the measurement framework. The teams that thrive will treat platform AI as a talented but self-interested employee: useful, fast, and never left alone with the company chequebook.
For finance leaders, the takeaway is simpler still. If 80% of spend will soon run through systems that profit when you spend more, independent measurement is not a nice-to-have — it is the only thing standing between an efficiency story and an expensive one.
Quick FAQ
How much US ad spend will AI control by 2028?
Gartner estimates 80% of US ad spending will flow through AI-powered platforms by 2028, with more than 70% of global spend moving through self-serve systems where AI materially influences outcomes.
What is 'machine bias' in ad platforms?
The tendency of platform AI to recommend outcomes that maximise the platform's revenue — effectively 'spend more with us' — rather than minimise the advertiser's cost per acquisition.
How can marketers stay in control?
Keep human oversight of budgets, define outcomes before deploying tools, limit platforms and variables, involve finance, and use independent third-party measurement rather than platform self-reporting.
AI media buying is the most useful employee you'll ever hire — and the one you can least afford to leave alone with the budget. The winning skill isn't running campaigns any more; it's setting the objective, auditing the output and owning independent measurement. Trust the platform's numbers last, not first. — Daniel Nikolla, Founder of Merx Marketing
The takeaway: as AI takes over media buying, your edge shifts from executing campaigns to setting objectives and owning independent measurement — because the platform profits when you spend more.
How much of your media budget already runs on platform AI — and who checks its homework? Tell us how you're keeping control.
If you would like to know more about this topic, please contact us on danieln@merxmarketing.co.uk
Source: Marketing Dive (marketingdive.com); Gartner (Eric Schmitt).
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Written by Daniel Nikolla, Founder of Merx Marketing Ltd and Marketing Minute
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