For most of Performance Max's life the honest answer to "how do I stop it showing for this search" was that you largely could not. Negative keywords were capped at a token handful and had to be requested through a Google representative, which meant the campaign type that reaches the widest, least predictable set of queries was also the one you had the least direct control over. That has changed, and the change is worth acting on because it closes the single biggest gap in the Performance Max wasted-spend story.
This post covers what actually changed in 2025, how to add negatives to Performance Max in the current interface, where to put them, and the important limit that everyone hits sooner or later: the inventory these negatives do not touch at all. It is the Performance Max companion to reading the Google Ads search terms report, where the same instincts about thematic negatives apply with less visibility to work from.
What actually changed in 2025
Three things changed, and together they turn Performance Max negatives from a manual favour into a normal part of account hygiene. First, the per-campaign limit rose from 100 to 10,000 negative keywords in March 2025, matching Search campaigns. Search Engine Land covered the expansion at the time as part of Google giving advertisers more control over Performance Max, and a limit that high effectively removes the ceiling for any normal account.
Second, adding those negatives became self-service. The campaign-level negative keyword form moved into the standard Google Ads interface over the course of 2025, so you no longer email a representative a spreadsheet and wait. Third, Performance Max gained support for shared negative keyword lists, with the rollout completing in August 2025. A shared list is the same object Search campaigns use — build it once in the shared library, attach it to as many Performance Max campaigns as you like, and one edit propagates everywhere. Alongside these, Google widened the search-term visibility Performance Max offers, so you have at least a coarse view of what themes are triggering the campaign.
How to add them in the current interface
There are three self-service routes into a Performance Max negative keyword, and they differ only in scope. At the campaign level, open the Performance Max campaign, go to its settings, and find the negative keywords section — you add words there exactly as you would type positive keywords, using the same broad, phrase and exact notation. At the account level, negative keywords live in the account settings and apply to every campaign, Performance Max included, which makes them the right home for terms that must never serve under any circumstances.
The third route is the shared negative keyword list, and for most accounts it is the one that matters. Build the list in the shared library, add your universal exclusions, then attach it to your Performance Max campaigns. The documented limits are up to 20 lists per account and up to 5,000 keywords per list; the per-campaign cap of 10,000 is separate, so a campaign can carry its own negatives and inherit several lists at once. Because a list attaches to the campaign and updates it in place, this is how you avoid the classic mess of the same exclusion pasted into a dozen campaigns and none of them in sync — the same placement logic described in the search terms report walkthrough.
The limit everyone hits: Search and Shopping only
Performance Max negative keywords apply only to Search and Shopping inventory. They do nothing on Display, YouTube, Gmail or Discover. This is the single most misunderstood thing about them, and it is easy to see why: you add a negative, the query stops showing on search, and you assume the exclusion is total. It is not. The video and display surfaces inside a Performance Max campaign are matched by audience signals, the asset group's creative and the landing page, not by the search query, so a negative keyword has no lever to pull there.
The practical consequence is that a negative keyword list is only half of Performance Max traffic control. To limit the non-search surfaces you use different tools: placement exclusions to cut specific apps, channels and sites; brand exclusion lists to keep the campaign off competitor and brand terms across surfaces; and content suitability settings for the video and display environment. Treat negative keywords as the instrument for the query-matched half of the campaign and those other controls for the rest, and you stop expecting one setting to do a job it was never wired to do.
What to actually block, given the thin reporting
Because Performance Max reports search categories and themes rather than a full query list, you write negatives from less evidence than a Search campaign gives you — so write themes, not strings. A single exact-match negative on one query is nearly useless here, because you cannot see the family of related queries it belongs to and Google is not going to show you most of them. A thematic negative on the word that made the search worthless retires the whole family, including the part you were never going to see.
Start with the exclusions that are true for the whole account regardless of what any report shows: employment language such as jobs, salary and career for a product that is not a job; free-and-DIY intent such as free, template and crack where those buyers never convert; informational intent such as what is, meaning and tutorial; and the names of adjacent products you do not sell. Put those in a shared list and attach it everywhere. Then use the search categories Performance Max does surface to spot themes specific to the account, and add those as you would from a Search campaign — checking each candidate word against your active keywords first, so a negative meant to block waste does not quietly strangle a product line a different campaign is bidding on. The same discipline from the wasted-spend hunt applies: block the theme, not the one string you happened to see.
Brand traffic, and why it hides in Performance Max
Performance Max mixes brand and non-brand queries and, unlike Search, does not let you split them cleanly in the interface — which is why so much of the campaign's reported performance is really brand traffic it would have won anyway. If someone searching your company name buys and the sale is attributed to Performance Max, the campaign's return on ad spend looks excellent while the incremental value is close to zero. Negative keywords are one of the levers you have to separate the two.
If you want Performance Max to chase genuinely new demand, add your brand terms as negatives to the campaign — or use the brand exclusion list, which is built for exactly this — so brand searches route to a dedicated brand Search campaign where you can see and bid on them deliberately. If instead you are happy for Performance Max to capture brand, leave them in but know that the headline numbers are flattered. Either choice is defensible; making it by default, and then reading the campaign's numbers as if brand were not in them, is the expensive mistake.
Fitting it into the audit routine
Review Performance Max negatives on the same cadence as the rest of the account — weekly for serious spenders, monthly for smaller ones, and always after a change to assets, budgets or feed, because those change what the campaign reaches for. The steps are the familiar ones with one adjustment for the thin reporting: open whatever search-term and category visibility the campaign offers, look for themes rather than individual queries, and write thematic negatives into a shared list wherever the exclusion is account-wide.
Keep the same written log you would keep for a Search campaign: what you excluded, at which level, and why, with a date. Negatives are the one part of an account whose effect is invisible — there is no report of the searches a negative prevented — and Performance Max makes that worse by showing you so little to begin with. If the campaign's volume drops a month after an aggressive negative session, the log is the only way to find which exclusion did it and reverse it. Over-negation is a silent failure mode, and the accounts most prone to it are the diligent ones.