If you run Campaign-level Broad Match or legacy Automatically Created Assets campaigns, Google is migrating them to AI Max automatically between September 1 and 30, 2026 (Search Engine Land on the migration timeline). New Campaign-level Broad Match and legacy ACA campaigns can no longer be created as of August 3, 2026, so the old system is already closed to new entrants and the flip is coming to existing accounts inside that window. Most of the advice circulating is about preparing before the migration. This post is about the pass you run after your campaigns flip — because the negatives that carried over were sized for a narrower account than the one AI Max gives you.
The critical fact is that negatives carry over but their fit does not. Google’s own guidance is that negative keywords generally transfer during migration but should be reviewed, since “some broad matching behavior can change” (Google Ads Developer Blog on the migration). A list that adequately fenced off junk under Campaign-level Broad Match can leave gaps once AI Max widens the queries your campaign is eligible for. This is the after-migration audit: confirm what survived, find what now leaks, and catch any exclusion that has turned from a useful fence into an over-block.
What the migration actually changes
AI Max is not a cosmetic rename of your existing campaign; it changes the matching surface. Where Campaign-level Broad Match expanded within a defined set of behaviours, AI Max applies broader query-intent matching and can serve on searches your old configuration would not have reached. That wider reach is the entire point of the product from Google’s side, and it is also the entire source of your new risk: every additional query AI Max can match is a query your negative list has never been tested against. The list did not shrink, but the space it has to cover grew.
This is why carry-over is reassuring but insufficient. Your account-level negatives, your shared lists, and your campaign-level negatives all survive the flip and stay attached, so nothing is deleted. But a negative keyword only does its job relative to the queries flowing past it, and those queries are exactly what changed. The audit’s job is to re-establish fit: to check that the negatives you kept still block the right things and still let the right things through, now that the volume and variety of what they are filtering has gone up. The conflict mechanics that decide whether a given negative even applies under AI Max are covered separately in AI Max negative keyword conflicts; this post is the account-level verification that sits on top of them.
Step one: confirm what carried over
Start by verifying, campaign by campaign, that your negative lists are still attached and populated after the flip. Open each migrated campaign and check that its shared negative lists are applied, that campaign-level negatives are present, and that account-level negatives still show as active. Migrations rarely drop these silently, but “rarely” is not “never,” and a campaign that lost its shared list during migration is now running AI Max’s wide matching with no exclusions at all — the worst possible combination. This is a five-minute check that prevents the most expensive failure mode.
While you are confirming attachment, confirm structure. AI Max campaigns should inherit the same deliberate hierarchy you built before — account-level negatives for universal junk, shared lists for reusable themes, campaign-level negatives for the specific — and the migration is a good moment to check that hierarchy survived intact. If a negative that belonged on a shared list ended up stranded on a single campaign, or a campaign-level exclusion is missing, fix it now against the model in how to structure negative keyword lists. A tidy structure is what makes the rest of the audit fast, because you know where each negative is supposed to live.
Step two: find what the wider matching lets in
The highest-value part of the audit is finding the junk AI Max’s broader matching now admits. Wait a few days after your campaign migrates so the report has data, then pull the search terms report for the migrated campaigns and sort by cost. You are looking for query types that were not there before — new intent clusters, adjacent products, informational searches — that the wider matching has surfaced. These are the leaks your old negative list never had to cover, and they are exactly where amplified reach turns into amplified waste if you do not act.
Group what you find rather than negating it one query at a time, because AI Max will keep producing variants of each new intent. If a whole cluster of research-intent queries has appeared, block the pattern that defines it with a phrase negative rather than chasing each string. This is the same pattern-grouping discipline that keeps any search terms review finite, and it matters more under AI Max precisely because the query surface is wider — the method is in grouping search terms into patterns. The report you are reading here is the one AI Max produces post-migration; the general reading method is the same as in the search terms report guide.
Step three: find negatives that now over-block
The mirror risk is a negative that was fine under narrow matching but now blocks traffic you want. Broad-match-era accounts often used negatives as fences — blocking a term in one ad group so it served in another — and AI Max’s different routing can turn a useful fence into a wall that stops good queries entirely. Review your broadest negatives, especially any negative phrase or negative broad entries added to solve a routing problem that no longer exists post-migration, and check the search terms report for converting queries that have suddenly gone quiet.
A sharp drop in impressions or conversions on a term right after migration, with no change to bids or budget, is the signature of a negative over-blocking under the new matching. Trace it back to the exclusion causing it and decide whether that negative still earns its place. This is over-negation in a new context, and the diagnostic approach — how to tell a suppressed-good-traffic problem from a genuine demand drop — is in when negative keywords cost you sales. Post-migration is exactly when this failure mode spikes, because negatives written for the old reach are suddenly interacting with the new one.
Step four: schedule the follow-up
One audit right after migration is not enough, because AI Max’s matching keeps evolving and your first post-flip report only shows a few days of data. Schedule a second, deeper review two to three weeks after your campaign migrates, once there is enough volume to see the stable pattern rather than the initial noise. By then the new query clusters AI Max favours will be clear, the over-blocks will have shown up as depressed terms, and you can make the structural negative decisions with confidence instead of reacting to a thin first week.
After that, fold AI Max campaigns into your normal weekly search-terms cadence and treat them as the higher-variance campaigns they are. Because AI Max reaches wider, it generates new queries faster, so the campaigns most worth reviewing weekly are the migrated ones. The before-migration preparation — tightening lists so a gap is not amplified — is covered in the AI Max migration search-terms checklist; this after-migration audit is its other half. Run the checklist before your September flip and this audit in the days after, and the migration becomes a controlled change rather than a month of silent drift.