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Google Ads AI Max migration: a small-account checklist before 1 October
Google is moving campaign-level broad match and Automatically Created Assets into AI Max in September, in place and with no way back. Neither Google's +7% nor smec's 35% lower ROAS measures what that does to your account: a small account should narrow its scope, check five settings, and let a holdout on its own bookings decide.
The Google Ads AI Max migration is running right now, and it is running on your account whether you asked for it or not. Between 1 and 30 September 2026, Google is automatically upgrading every Search campaign that uses the campaign-level broad match setting or Automatically Created Assets to AI Max, campaign by campaign, in place (Google Ads Developers Blog). Once a campaign has moved there is no path back to the legacy settings. By 1 October you should assume every eligible campaign is an AI Max campaign and manage it as one.
What the Google Ads AI Max migration actually changes
AI Max is not a new campaign type. Google migrates campaigns in place, and Improvado notes that campaign IDs carry through. Google says AI Max is switched on "with settings configured to mirror your legacy setup" (Google). Campaigns that used Automatically Created Assets get search term matching and text customization switched on; campaigns that used campaign-level broad match get search term matching switched on. The timeline was set out by Search Engine Land: creating new campaigns with campaign-level broad match or legacy Automatically Created Assets has been blocked since 3 August, and the automatic upgrade runs 1 to 30 September. Dynamic Search Ads follow in February 2027, after Google pushed that part back in June because advertisers asked for more time.
Search term matching is the change underneath the campaign. It lets the system reach queries that are not in your keyword list, using your assets and landing pages as the signal. Final URL expansion, which lets the system send clicks to pages you did not choose, is a separate setting, and the developer announcement leaves it off in both kinds of migrated campaign. It stays off until someone turns it on. For anyone who carries Google Ads data into a spreadsheet or a BI tool, Improvado points to new reporting segments and views, and to one trap that only applies once final URL expansion is on: the page a person landed on is no longer always the final URL stored on the ad, so "any join keyed on that URL degrades quietly."
The claim gap: whose number is yours?
Google's figure for AI Max is 7% more conversions or conversion value at a similar CPA or ROAS. The comparison behind it matters: campaigns using the full feature set, search term matching, text customization and final URL expansion together, against campaigns using search term matching alone, from Google's internal 2026 data for advertisers outside retail (Google, April 2026). It does not compare AI Max with the legacy setup, and a migrated broad match campaign receives search term matching only.
The figure usually set against it comes from smec (Smarter Ecommerce), a PPC software vendor. In November 2025 it analysed more than 250 retail campaigns and found that AI Max traffic, where advertisers had opted in, returned about 35% lower ROAS than the exact, phrase and broad match traffic in the same campaigns (PPC Land).
The two numbers do not belong on one chart, and one cannot be subtracted from the other. Google's is a change in conversion volume against a partial AI Max setup outside retail. smec's is a ratio of return against keyword match types inside retail, measured five months earlier by a different company. Neither measures the September migration, and both can be true at once.
Neither number is yours. The only way to find out what AI Max does to a
specific local account is to withhold it somewhere comparable and count
the difference in bookings, not in platform-reported conversions. That
is the holdout test, and this month it
has a natural design: if the migration has already hit one campaign
and not yet another comparable one, you have a temporary control group
for free. Log the dates. The Google Ads API records each campaign's
migration time (aca_migration_date_time and
broad_match_migration_date_time).
| smec (Smarter Ecommerce) | ||
|---|---|---|
| Figure | +7% conversions or conversion value, at similar CPA or ROAS | About 35% lower ROAS |
| Compared | Full AI Max feature set against search term matching alone | Opt-in AI Max traffic against exact, phrase and broad match in the same campaigns |
| Advertisers | Outside retail | More than 250 retail campaigns |
| Measured by | Google, internal data | smec, a PPC software vendor |
| Published | April 2026 | November 2025 |
Under the spend floor, automation has nothing to learn from
AI Max is a learning system, and it learns from conversions. An account feeding it 12 conversions a month is not a smaller version of an account feeding it 40; it is a different, noisier thing. That is the logic of the spend floor: below roughly 30 conversions a month, "optimisation" is a reaction to noise.
The practical consequence for a small local account is counter-intuitive. The migration gives the system more freedom exactly when it has the least data. If the account sits under the floor, narrow the scope before the system gets more room: before the upgrade if the campaign has not migrated yet, and now if it has. One service, one campaign, exact match, so the conversions the system does see are concentrated. Search term matching can be switched off per campaign; on a sub-floor account that is usually the right default until the conversion count justifies it.
The five settings to check on a small account
- Confirm which campaigns are in scope. Open every active Search campaign and look for Automatically Created Assets or campaign-level broad match. If either is on, the campaign is in the migration path. Campaigns without either are untouched.
- Pin down the pre-migration baseline now. Cost per booking, search term report, and top landing pages for the weeks before each campaign migrated, exported and dated. Without it you cannot, as Seafoam puts it, "tell the difference between 'AI Max is working' and 'September is a good month.'"
- Audit negatives and brand controls, before migration where you still can. Broader matching reaches searches your negative lists were never written for, so thin negative coverage turns straight into spend on the wrong queries. Brand inclusions and exclusions carry over, but check them.
- Decide on final URL expansion. Migration leaves it off, and it stays off until someone switches it on. If you do switch it on, first exclude the pages you never want paid traffic on (careers, blog archives, a dormant service).
- Check the reporting join if final URL expansion is on. If landing-page URLs feed a report or a dashboard, the landing page and the ad's final URL can stop matching. Test the join in the first week of October.
How to judge the result in October
Judge it the way the bad-case forecast judges any change: against a bad, base and good range with the expectation set at the bad case, on the business's own records, over a full buying cycle. Compare October's cost per booking with the September baseline, not October's platform conversions with September's. If a comparable campaign or district stayed on legacy settings for even two weeks, that fortnight is your control: too short to pin the effect down to a percentage, long enough to rule out a claim the difference plainly contradicts. And if the number moved in the wrong direction, the arithmetic does not forbid switching search term matching off again; it forbids pretending Google's +7% was a promise made to you.
Frequently asked questions
- Can I opt out of the AI Max migration?
Not after a campaign has migrated. Before it migrates, disabling Automatically Created Assets and the campaign-level broad match setting removes the campaign from scope. After migration, individual features such as search term matching can still be switched off per campaign.
- When do Dynamic Search Ads move to AI Max?
February 2027. Google pushed the Dynamic Search Ads upgrade back in June 2026 after advertisers asked for more time; Search Engine Land reports in-account notices from September and reminders in January.
- Does the migration change my campaign IDs or conversion tracking?
Google migrates campaigns in place, and Improvado notes that campaign IDs carry through. Conversion actions carry over, but verify them alongside location targeting, ad schedules and negative lists after the upgrade.
- Is the +7% figure reliable?
It is Google's own internal 2026 measurement, it excludes retail, and it compares the full AI Max feature set with search term matching alone, not with your legacy setup. Treat it as the good case in a forecast, not the plan. Your account's number comes from a holdout on your own bookings.
Sources
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