Negative Keywords in the AI Max Era: Still Your Only Real Lever
Google spent the last two years taking levers away from search advertisers. Match types got looser, keyword lists started to matter less, and AI Max now decides which queries you enter, which headline the user sees and which page they land on.
One control survived all of it intact. Negative keywords are still the only lever that tells Google, in plain terms, where your money must not go. Google’s own AI Max documentation confirms that negatives are respected even with AI Max switched on (Google Ads Help).
That matters more than it sounds. When the system is choosing the queries for you, the quality of your exclusions becomes the quality of your traffic. In the accounts we manage, the gap between a profitable AI Max campaign and an expensive one is rarely bidding or creative. It is almost always what the advertiser told Google to stay away from.
This guide covers what AI Max actually changes, why negative keywords carry more weight now than they did under exact match, and the exact framework our paid marketing team uses to keep AI Max spend clean.
What AI Max for Search campaigns actually changes
AI Max is not a new campaign type. It is a setting layered on top of a standard Search campaign that hands three decisions over to Google’s AI.
| What AI Max controls | What it does | What you lose |
|---|---|---|
| Search term matching | Expands beyond your keywords using broad match, plus asset-based and landing page-based matching that needs no keyword at all | The keyword list as a hard boundary on which queries you enter |
| Text customization | Rewrites and generates headlines and descriptions from your site and existing ads | Full control of the message, and RSA pinning when combined with Final URL expansion |
| Final URL expansion | Sends users to whichever page on your site Google thinks fits the query | Control over which page each query lands on |
Google describes search term matching as broad match combined with keywordless technology (Google Ads Help). Read that carefully. Your ad can now enter auctions for queries that no keyword in your account would have triggered, because Google matched them to your ad copy or your landing page content instead.
The upside is real. You pick up converting queries you never thought to target. The downside is just as real: every vague line on your website and every loose phrase in your ads is now a potential entry point for spend.
Two technical details worth knowing before you switch it on. Search term matching does not work with manual CPC, so it needs a Smart Bidding strategy to function. And AI Max traffic is labelled with its own match source in the search terms report, which is where all the negative keyword work in this guide begins.
Why negative keywords matter more in the AI Max era, not less
Under exact match, your keyword list defined your traffic. Negatives were a cleanup job. Under AI Max, the logic flips: the AI defines your traffic, and your negatives are the only hard boundary you still own.
Everything else you configure is a signal. Your keywords, your ad copy, your landing pages, your audience data: Google reads all of them as hints and weighs them against its own prediction of what will convert. A negative keyword is different. It is an instruction, not a suggestion, and the system has to follow it.
That difference shows up in three places.
The AI optimises toward your conversion data, not your business. If your tracking counts a newsletter signup the same as a demo request, AI Max will happily chase cheap signups. Negatives let you shut out whole intent classes like “free”, “template” or “jobs” that inflate conversion volume without adding revenue.
Keywordless matching borrows from your website. A careers page, a blog post about industry salaries or a support article can quietly pull in queries you would never bid on. Some of that is fixed with URL exclusions, but the query itself still needs to be blocked.
Spend scales before learning catches up. In the first few weeks, AI Max explores aggressively. Every irrelevant query it tests is paid for with your budget. A strong negative list before launch shortens that expensive exploration phase considerably.
If cost per lead is already your pressure point, this is usually the fastest win available. We cover the wider playbook in our guide on how to lower cost per lead without cutting ad spend.
How negative keywords behave inside AI Max
Negatives work the same way in AI Max as in any Search campaign, which is exactly why so many advertisers get them wrong. The rules were always stricter than people assume, and AI Max simply exposes the gaps faster.
Negatives do not cover close variants. A positive broad match keyword will match plurals, misspellings and synonyms. A negative keyword will not. If you exclude “cheap”, you have not excluded “cheapest” or “low cost”. Under AI Max, where the query pool is far wider, those gaps get found and paid for within days.
Match type still decides how much you block. Negative broad blocks any query containing all your words in any order. Negative phrase blocks that exact sequence of words. Negative exact blocks only that precise query. Use broad for intent you never want (“jobs”, “salary”, “course”) and exact when you want to kill one query without collateral damage.
Negatives are not the only exclusion, and using the wrong one costs you. Google’s own developer documentation offers a simple triage that we use with every client (Google Ads API docs):
| Problem you see | Right tool | Level |
|---|---|---|
| Irrelevant query triggering your ad | Negative keyword | Ad group, campaign, account or shared list |
| Right query, wrong landing page | URL exclusion | Campaign (needs text customization and Final URL expansion on) |
| AI Max eating your own brand traffic or chasing competitor names | Brand exclusion | Campaign |
| Ads should only show with your own brand | Brand inclusion | Campaign or ad group |
One practical example. If a single blog post keeps attracting informational queries, adding thirty negatives is the slow fix. One URL exclusion on that post solves the routing problem, and a handful of negative broad terms covers the intent. Use both, but in that order.
The negative keyword framework we use for AI Max campaigns
This is the process our team runs on every account before and after AI Max goes live. It is built in layers, because one giant list nobody maintains is how most accounts end up leaking spend.
Before you switch AI Max on
- Fix conversion tracking first. AI Max optimises toward whatever you count as a conversion. If micro conversions or duplicate events sit in your primary goal, no negative list will save you. Our GA4 guide for marketers covers the setup we check.
- Build an account-level universal list. These are terms that are wrong for your business in every campaign: “jobs”, “careers”, “salary”, “internship”, “free download”, “pdf”, “reddit”, “meaning”, “definition”, “diy”. Tailor it to your vertical. A SaaS brand probably wants “open source” and “crack” on it. A clinic wants “at home” and “side effects”.
- Mine at least 90 days of search terms. Pull every query that spent money without converting from your existing broad and phrase campaigns. These are the patterns AI Max will find again, only faster.
- Add campaign-level intent negatives. Each campaign should block the intent that belongs to a different campaign. Your non-brand campaign blocks your brand name. Your premium service campaign blocks “cheap” and “affordable” if those leads never close.
- Set brand exclusions and URL exclusions. Exclude your own brand from non-brand AI Max campaigns so you are not paying non-brand CPCs to steal clicks your brand campaign would win anyway. Exclude careers, legal, login and support pages from Final URL expansion.
During the first 30 days
- Review search terms twice a week, filtered to the AI Max match source. This is where the exploration spend goes.
- Look for patterns, not single queries. One bad query is noise. Five queries sharing the word “course” is a negative broad keyword.
- Set a clear spend threshold. Our working rule is any query that has spent more than your target CPA without a conversion gets reviewed that day. Some will be early converters. Most will not.
- Log every negative you add and why. It sounds like admin. It is the only way to undo a mistake three months later when a good query stops showing.
Ongoing
- Move to a weekly review once the campaign stabilises, and a monthly audit of the shared lists themselves.
- Check for over-blocking. Run a search terms comparison against the previous period. If impression share drops on queries you want, a negative broad term is probably catching more than intended.
- Promote proven AI Max queries into keywords. When AI Max finds a converting query you never targeted, add it as a keyword. That gives you a controlled bid on it and frees the AI to keep exploring.
Five mistakes that quietly kill AI Max performance
Turning AI Max on with default settings. It is tempting to accept the recommendation in the Google Ads interface and see what happens. What usually happens is a CPA spike in week one, a panicked pause in week two and a conclusion that “AI Max doesn’t work for us”. The feature was never given a fair test.
Treating the search terms report as a monthly task. Under exact match, a monthly review was fine. Under AI Max, a month of unchecked exploration can burn a meaningful share of the budget on queries a five-minute review would have caught.
Over-correcting with aggressive negatives. Panic leads to negative broad terms like “best” or “price” that block your highest-intent buyers along with the junk. Every negative should be tested against the question: would a real customer ever search this?
Ignoring overlap with Performance Max. If you run PMax alongside AI Max Search, both campaigns can compete for the same queries. Use brand exclusions and account-level negatives deliberately so each campaign has a clear job, rather than letting Google decide which one wins.
Expecting negatives to fix a weak offer. Negative keywords stop bad traffic. They cannot make good traffic convert. If your landing page or offer is the problem, the cleanest search terms report in the world will not rescue the numbers. Before deciding which channel deserves the budget, it is worth reading our breakdown of Google Ads vs Meta Ads.
The bottom line
AI Max is not going away, and fighting it is a losing strategy. The advertisers winning with it are not the ones with the cleverest bidding setup. They are the ones who decided, before launch, exactly where their budget should never go, and who keep enforcing that decision every week.
Google now chooses the query, the headline and the landing page. You still choose what is off limits. Treat that as the most important job in your account, because it is.
If your AI Max campaigns are spending more than they should, or you want a second pair of eyes before switching it on, our team can audit your search terms, exclusions and conversion setup. Explore our paid marketing services and AI marketing services, or book a free audit and we will show you exactly where the spend is leaking.
Frequently asked questions
Does AI Max respect negative keywords?
Yes. Google confirms that negative keywords are respected when AI Max is turned on. That includes ad group, campaign, account-level and shared negative keyword lists.
Do negative keywords block close variants in AI Max?
No. Negative keywords never match close variants such as plurals, misspellings or synonyms. You need to add those variations yourself, which matters more under AI Max because its query pool is much wider.
What is the difference between negative keywords and brand exclusions in AI Max?
Negative keywords block specific search terms. Brand exclusions stop your ads from showing against named brands, including your own, and are mainly used to prevent AI Max from cannibalising a separate branded campaign.
How often should I review search terms in an AI Max campaign?
Twice a week for the first 30 days, filtered to the AI Max match source, then weekly once performance stabilises. A monthly audit of your shared negative lists helps catch over-blocking.
Can I use AI Max with manual CPC bidding?
The search term matching feature does not work with manual CPC. You need a Smart Bidding strategy such as Maximize Conversions or Target CPA for AI Max to expand your reach.
Should I add negatives before or after enabling AI Max?
Before. Build an account-level list and mine at least 90 days of historical search terms first. It shortens the expensive exploration phase and gives the AI cleaner signals from day one.
