Google started auto-migrating Search campaigns to AI Max on September 1, 2026. Here is what changed, who is affected, and what service businesses must do this week.
Ido Cohen · Published 2026-09-05 · Paid Advertising
Google began forcibly migrating your Search ad campaigns to its AI-powered system called AI Max on September 1, 2026 — and if you haven't checked your account yet, the switch may already be in progress. This isn't a beta test or an optional upgrade: it's an automatic, account-wide change that touches how your ads match searches, what headlines they display, and which landing pages they send traffic to. If you're a plumber, HVAC tech, dentist, real estate agent, or any other service business spending money on Google Search Ads, this is the most consequential platform change to hit your account in years.
Google flipped the switch on a mandatory migration that's been telegraphed since April. Starting September 1 and rolling out gradually through September 30, Google is automatically upgrading two legacy campaign types to AI Max for Search campaigns: any campaign using Campaign-level Broad Match and any campaign running Automatically Created Assets (ACA) — Google's older system for auto-generating ad copy.
According to Search Engine Land's coverage of the official timeline, the September 1–30 window covers automatic migration of Campaign-level Broad Match and ACA campaigns to AI Max, with Dynamic Search Ads (DSA) following in a separate wave beginning February 2027. Google stopped allowing advertisers to create new Campaign-level Broad Match or legacy ACA campaigns back on August 3, so the population of affected accounts is frozen — you're either in the migration path or you're not, and that answer became final weeks ago.
The ad firm and agency community flagged the quiet rollout: Google announced this via direct email to affected advertisers in early August, but published no accompanying blog post at the time, meaning a large share of business owners had no idea this was coming. If you're managing your own ads — or if your agency hasn't mentioned this to you — there's a real chance your campaigns are being restructured right now without your knowledge.
AI Max for Search campaigns is Google's unified AI-powered serving mode built on its Gemini models. Think of it as Google replacing your manual steering wheel with an autopilot system. It bundles three major capabilities into one:
As Google's own product blog put it, AI Max brings "the best of Google AI into your Search campaigns" by handling targeting, creative generation, and URL selection simultaneously. The upside is that it can capture demand from searches you'd never have thought to bid on. The downside is less manual control over every one of those three levers.
For a local service business — say, a roofing contractor in Phoenix — this means your "roof repair" campaign could start matching "storm damage home insurance claim process" if Google's AI decides that's close enough. Whether that's a win or a waste depends entirely on what guardrails you set up before the migration hit.
Google claims AI Max delivers an average of 7% more conversions or conversion value at a similar CPA or ROAS when using the full feature suite, compared to using search term matching alone. That's the number they'll show in every deck and help-center article.
Here's the other number: independent testing across more than 250 retail campaigns found a 35% ROAS decline after migration, according to PPC Land's 2026 data cited by agency reporting. That's a 42-percentage-point gap between what Google reports and what advertisers are actually measuring.
Why the gap? A few reasons:
1. Google measures conversions differently in AI Max — the platform can attribute more events to the campaign, making numbers look better even if actual business results don't improve.
2. Broad query matching inflates volume but often brings in lower-intent traffic.
3. URL expansion can send users to pages that weren't designed to convert, quietly hurting your cost-per-lead without an obvious culprit.
4. Service businesses are particularly exposed because your qualified lead is narrow. A dentist running implant ads doesn't want to show up for "what is a tooth implant" research queries. An HVAC company doesn't want to pay for clicks from renters researching whether their landlord is responsible for AC repairs.
One important note: approximately 84% of advertisers experienced neutral or negative results when measuring overall account performance — not just within the AI Max campaign itself — according to data compiled by Didoo.ai from early migration cohorts. That's worth keeping in perspective when your account rep tells you the numbers look good.
Not every campaign in your account is being migrated. Here's the breakdown:
The critical distinction on Broad Match: only the campaign-level setting triggers the automatic upgrade. If you have individual broad match keywords inside an ad group, that does NOT trigger migration. Only the campaign-level toggle does.
To check your exposure right now, open Google Ads, go to Campaigns, filter by "Status: Active," and look for any campaign with Campaign-level Broad Match enabled or ACA turned on. If you see either, that campaign is in the migration window — and depending on where Google's rolling rollout is in your account, it may have already been switched.
The silver lining: Google says existing brand inclusions and brand exclusion lists carry over automatically when a campaign migrates. So if you had competitor exclusions or brand protections built in, they're supposed to transfer. Verify this rather than assume it.
Once your campaign migrates to AI Max, you're working with a different set of controls. The old levers don't disappear entirely — they just move and some become softer.
What you still control:
What AI Max now controls:
The AI Brief is actually worth paying attention to. It's Google's mechanism for giving the AI more context — think of it as writing a one-paragraph brief about your business that the algorithm uses when making decisions. A roofing company that writes "we only serve residential homeowners in Maricopa County, focus on storm damage and full replacements, minimum project value $8,000" gives AI Max a much cleaner signal than a blank brief.
Microsoft made the same move this month: its own AI Max equivalent reached general availability and is now on by default for all new Search campaigns, per Seafoam Media's September briefing. So this isn't just Google. Both major search ad platforms are moving in the same direction simultaneously.
The migration is already in progress. Here's a prioritized action list for service business owners:
1. Audit your account today. Log into Google Ads and identify every campaign with Campaign-level Broad Match or Automatically Created Assets enabled. List them. This takes 10 minutes.
2. Pull a performance baseline before changes compound. Export your CPA, ROAS, conversion volume, and top search terms for the last 30 days for each affected campaign. You need a pre-migration benchmark so you can tell the difference between "AI Max is working" and "September is just a slower month."
3. Build out your negative keyword list aggressively. This is the single most important control you have post-migration. AI Max will expand your reach; negatives are how you stop it from going somewhere damaging. Add every irrelevant service, every geographic area you don't serve, every informational query type (how, what is, definition, DIY) that won't convert for your business.
4. Disable Final URL Expansion if your site isn't built for it. If you only have one or two landing pages that actually convert — which is common for local service businesses — turn this feature off. You don't want Google sending urgent plumbing emergency clicks to your blog post about pipe maintenance.
5. Write an AI Brief. Spend 15 minutes writing a clear description of your business, your ideal customer, your service area, and the jobs you don't want. This is now a real lever, not a checkbox.
6. Set a 30-day check-in alert. By end of September, all eligible campaigns will have migrated. Schedule a review for October 7 to compare your CPA and search term report against your baseline. If you see cost-per-lead climb more than 20% without a corresponding lift in volume, start there.
7. Call your agency. If someone else manages your Google Ads, ask them specifically: "Which of our campaigns were migrated to AI Max in September, and what did you change before the migration?" If they don't have a clear answer, that's important information.
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What is Google AI Max for Search, and how is it different from what I had before?
AI Max for Search is Google's AI-powered campaign system that replaces manual targeting, creative, and URL controls with an automated system built on Google's Gemini models. Unlike traditional Search campaigns where you chose specific keywords and wrote fixed ads, AI Max matches your ads to searches it judges as relevant, generates headline variations dynamically, and can redirect users to different pages on your site than the one you specified. The key shift is from manual control to AI-driven inference, with guardrails you set rather than decisions you make.
My campaigns haven't migrated yet — is there anything I can do to prepare?
Yes. Since the rollout is gradual through September 30, some campaigns won't flip until later in the month. Use the time to build your negative keyword list, pull a performance baseline, disable Final URL Expansion if your site has limited landing pages, and write an AI Brief that gives the algorithm accurate context about your business. Campaigns that enter AI Max with strong guardrails set tend to perform better than those that get migrated cold.
Does this affect my campaigns if I only use exact match or phrase match keywords?
Only if you also have Campaign-level Broad Match or legacy Automatically Created Assets enabled. Standard Responsive Search Ads using keyword-level match types — including individual broad match keywords at the keyword level — are not part of the September migration. Dynamic Search Ads have their own separate migration timeline beginning February 2027.
Google says AI Max delivers 7% more conversions — should I trust that number?
Treat it with serious skepticism, especially for service businesses. Google's figure comes from internal data and measures conversions as the platform counts them, which can include attribution that looks better on paper than in your actual revenue. Independent data from agency and third-party testing has shown meaningfully worse ROAS outcomes for many advertisers after migration. Set your own pre-migration baseline and measure against it — don't take the platform's word for performance.
What is the AI Brief and how should I use it?
The AI Brief is a plain-language input field inside AI Max where you describe your business, your messaging priorities, and your target audience in your own words. Powered by Gemini, it gives the AI additional context when making targeting and creative decisions. For a service business, a strong AI Brief should include your service area, the specific jobs you do (and don't do), your typical customer, and any messaging constraints — for example, "we are a licensed HVAC contractor serving residential customers only in Dallas-Fort Worth, we do not offer commercial HVAC, and our minimum service call fee is $150." The more specific, the better the guardrail.
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