Lunio’s 2026 AI Max data study shows that AI Max adoption heavily correlates with increased invalid traffic rates. And while retail users are most affected right now, lead gen and other sectors will be impacted as AI Max is rolled out to thousands more advertisers from September 2026.

Get ahead of the curve and find out how AI Max is affecting IVT rates in real campaigns. Plus, see how to protect automated paid media campaigns from wasted ad spend and corrupt data signals.

Introduction

AI Max is the fastest-growing AI-powered Search ads product. It helps performance marketers move from keyword- to intent-based targeting in just a few clicks. And according to Google, advertisers who use AI Max will see 14% more conversions at a similar return on their ad spend.

But this might not be the full picture. Early adopters found AI Max posed significant risks to performance. In 2025, Lunio shared data indicating that AI Max could significantly increase invalid traffic (IVT) rates. Our client saw a 35% increase in IVT in one month with AI Max activated, leading to a surge in wasted ad spend.

And our 2026 data shows the problem isn’t confined to individual clients — it’s affecting AI Max users at scale. After analyzing ~114.5m search clicks, we found AI Max could increase invalid traffic rates by 35% across the board, leading to a huge uptick in wasted ad spend and compromised paid media performance.

Here, we share our AI Max invalid traffic 2026 dataset analysis, compare it to our 2025 findings, and explore how it maps to AI Max research from other analysts. Plus, you’ll discover why you should take note of these findings right now, and how to mitigate the impact of AI Max-related IVT on your campaigns.

2026 dataset: IVT in AI Max vs standard Search campaigns

Over nine months, Lunio tracked the IVT rate across ~114.5m clicks on standard Search and AI Max Search campaigns. In this time, AI Max went from having the lowest to the highest IVT rate within Search, resulting in a huge 114% increase in invalid clicks.

AI Max began approximately a third cleaner than standard Search and ended 72% dirtier. Even small initial volumes of IVT can corrupt data signals in automated campaign types, as AI models depend on existing traffic signals to seek out new similar users. This creates a negative feedback loop that compounds the IVT problem within AI Max campaigns.

Retail advertisers are currently affected more than most. Retail accounted for a third of all search clicks in Q4 2025, but a quarter of invalid clicks. By Q2 2026, retail had generated 55% of all search clicks, but 68% of all invalid clicks.

This indicates a big shift in the proportion of IVT affecting retail businesses — over nine months, retail went from being underrepresented in IVT to significantly overrepresented. This coincides with a massive increase in AI Max adoption among retail businesses; AI Max accounted for approximately 33% of retail search clicks in Q4 2025, rising to 55% by Q2 2026.

Despite the market shrinking, the share of retail advertisers using AI Max actually increased. And since AI Max appears to be responsible for the rise in IVT, this has seismic implications, especially for retail advertisers.

Invalid traffic outpaces total click share in AI Max

Total search volume fell over the nine month period, but the proportion of AI Max retail spend grew. Over this time, the rate of IVT started to outpace the total click share:

As retail advertisers shifted more budget toward AI Max, a growing share of the traffic they received was invalid — highlighting the risk of spending more on AI Max right now. In fact, by the time AI Max accounted for more than half of retail budgets, it also generated 68% of all invalid Search clicks. So invalid clicks became disproportionately concentrated where AI Max adoption was highest.

Lunio’s 2025 dataset — what sounded the alarm bells

We first flagged this problem back in 2025, after discovering IVT changes in one Lunio client account. The brand had been using Lunio’s ad traffic verification platform for 12 months prior to January 2025. With Lunio, they cut their overall average IVT rate in half across their Google Search campaigns, reducing it from just over 7% to a stable baseline average of 3.7%. From January to May 2025, the brand maintained this baseline average IVT rate, as you can see in the chart below.

In May 2025, the brand took part in the AI Max open beta, during which AI Max was enabled on 404 of their Search campaigns. 491 campaigns were unchanged, and ran without AI Max, giving us unique insights into the impact of AI Max on IVT rates.

Our data science team performed statistical analysis across all campaigns to assess the impact of enabling AI Max on IVT. In the chart above, you can see the actual rate of IVT — the blue line — starts to increase when AI Max is activated. (The red line denotes the expected rate of IVT had AI Max not been activated.)

Here’s what we found:

• For Search campaigns with AI Max enabled, the average IVT rate rose from 3.7% to 5%, with highs of up to 6% reported. 
• The change in the baseline IVT rate (from 3.7% to 5%) represents a 35% increase in the amount of IVT AI Max-enabled campaigns were exposed to.
• For accounts spending large amounts (like this client), this represents a significant increase in wasted ad spend. 

Our data science team explains how they analyzed the results:

“We performed statistical analysis on both sets of campaigns to assess the impact of AI Max. We started with an initial difference-in-difference test to assess the first impressions. This involved looking at the control (non-AI Max) and treatment (AI Max) campaigns before and after the AI Max adoption date, and comparing the differences between their averages. 

The final test statistic suggested a significant increase associated with the treatment group’s IVT levels post-AI Max adoption compared to the control. The IVT seemed to increase in the treatment group.”

Is the increase in IVT definitely due to AI Max?

The team assessed these findings against other possible explanations, such as seasonality and other external trends. But we found that these were unlikely to account for the increase in IVT. The two charts below show average IVT rates for the account’s non-AI Max campaigns across a similar period in 2024 and 2025:

“We compared trends to the same time period last year to gauge seasonal trends, as well as sense checking against trends across the year. After comparing the broad characteristics of both trends (standard deviation and slope), they were considered similar. So it can be safely assumed that the change in IVT wouldn’t be due to seasonal trends.”

Additionally, we checked the account’s 2024 IVT data to identify any trends that occurred in the previous year (prior to using Lunio). But as you can see from the chart below, their IVT rate remained consistent throughout the year, with one spike occurring around October:

On reviewing this data, the team said:

“The 2024 IVT rate data shows that the IVT rate broadly fluctuated around 4.5%, with no discernible trend. This adds to the assumption that any IVT rate change after AI Max adoption won't be due to external trends and can be assumed to be caused by AI Max features.”

So if AI Max is responsible for this rise in invalid traffic, what would the IVT rate have looked like if the brand hadn’t activated AI Max for those campaigns? Our team forecasted the predicted IVT rate without AI Max to provide a clear visual comparison:

“Based on the difference-in-difference test, I wanted to rigorously test the outcome, and forecast the pre-AI Max IVT rates to see what IVT rates could look like if AI Max wasn’t adopted.

The red line on the chart is a simple linear forecast based only on the company’s IVT rates before AI Max adoption. In line with the 2024 trend, the forecast predicts a steady average IVT rate if they hadn’t activated AI Max.

However, the actual IVT rate has increased in this period instead, suggesting that AI Max is driving up IVT rates.”

It’s important to acknowledge that these are early-stage insights from a single account, so they’re not necessarily fully representative. But the data spans almost 900 campaigns, so the results are significant, and can give an indication of AI Max’s broader performance.

Why AI Max increases invalid traffic

AI Max increases your exposure to invalid traffic because it removes many of the manual levers that help control your targeting.

Google’s AI uses broad match and keywordless technology to increase your reach, meaning your ads are served against queries you’ve never specified. Additionally, AI Max uses Final URL expansion to send users to landing pages you’ve never nominated, unless you switch off this setting after enabling AI Max.

Broader inventory with lower visibility and control leaves more room for invalid traffic to infiltrate your campaigns: which is just one of the risks of using AI Max.

What other researchers are finding

There’s no question that AI Max can expand your reach. But whether it expands into the areas you want is another matter. Analysis of 2026 data from Smarter Ecommerce found that AI Max generated 13% more conversions among 600+ retail advertising accounts — but cost per acquisition was around 16% higher.

We Know Growth’s Matthew Gatley also reported CPAs that are 13.6% higher than the campaign baseline, and Ezra Sackett, director of paid search at Monks, found that a huge 99% of AI Max impressions had zero conversions across ~30K search terms. So while AI Max is expanding your visibility, this isn’t always translating to tangible results.

Smec also found that advertisers using AI Max had wildly different ROAS results. Some advertisers achieved a significant increase of +42%, while others found ROAS performance dropped by -35%. Less than a quarter of advertisers (22%) saw similar ROAS to baseline performance.

So whether you’ll improve your ROAS with AI Max is a bit of a gamble. You could get lucky and substantially increase your return, but it’s far from a given.

Other researchers have found AI Max may be taking undue credit for certain results. Brad Geddes at Adalysis suggests AI Max may be treating all keywords as broad match, regardless of the specified type. That means it could be taking credit for conversions that existing exact and phrase match keywords would have won anyway, artificially inflating its own performance.

Smec also found that AI Max caused unwanted expansion into competitor traffic. In one AI Max-enabled campaign, brand terms for a single competitor accounted for 69% of total impressions. Smec estimated that including all competitor terms would increase the impression share to more than 80%. (Smec’s Mike Ryan has highlighted brand interference as one of five common AI Max mistakes advertisers make.)

Creating conflict between you and your competitors isn’t just bad for your brand. It can also lead to escalating costs, thanks to increased click competition and a heightened risk of clicks from irrelevant users who are actively searching for other brands.

Multiple paid media experts have independently found that AI Max can compromise performance marketing efficiency, so Google’s stats don’t give the full picture. And as well as compromising ROAS, CPAs, and competitor relationships, Lunio has shown that AI Max could increase your exposure to IVT, too.

What does this mean for marketers?

Increased invalid traffic will inevitably lead to more wasted ad spend, as bots and other fake users click your ads with zero chance of conversion. And the more IVT you have, the more of your budget you could lose. So seeing a rise in IVT due to AI Max activation is a worry, especially for accounts that spend heavily on Google Search.

Invalid traffic has other serious implications for advertisers. As well as draining your ad budget, high levels of IVT can make your data unreliable, and force your sales team to spend time weeding out the fake leads from your CRM. Ultimately it makes your sales and marketing processes much less efficient, and can even impact performance if you’re using Performance Max and other automated campaign types, which rely on clean, accurate data to generate quality conversions. 

If you’re already using AI Max (or planning to in future), it’s worth auditing your traffic to see how much IVT your ads are being exposed to. Lunio offers a free 14-day traffic audit to reveal your IVT rate, so you can decide whether it makes commercial sense to deal with it at this stage.

IVT rates of less than 2% aren’t normally too much of a concern. But if you’re seeing IVT rates of 5% or more in your Google Search campaigns (before or after AI Max adoption), there’s usually a strong business case to tackle it. This can reduce financial and time inefficiencies, leaving you in a better position to advertise to genuine users with a real chance of conversion.

Why this matters right now

If you’re here, you’re probably already using AI Max (or at least thinking about it). But soon the matter could be out of your hands. Google has set out a clear timetable for expanding AI Max to more advertisers, including those using Dynamic Search Ads:

• September 2026 — Campaigns using automatically created assets (ACA) and campaign-level broad match settings will automatically be switched to AI Max.
• February 2027 — Dynamic Search Ads (DSA) campaigns will be sunsetted and automatically switched to AI Max.

September marks the start of peak trading times, especially for retail businesses. So it’s important to be prepared for this major shift. Establishing an invalid traffic baseline before the upgrade takes place will let you monitor the impact of AI Max on your IVT rate when you’re auditing AI Max performance in future.

What actually reduces invalid traffic from AI Max

If you suspect you have an IVT problem within your AI Max campaigns, there are a few ways to reduce your exposure in-platform:

• Add negative keywords at campaign- and ad group-level to limit which queries your ads are shown for
• Add URL exclusions to reduce exposure via irrelevant landing pages
• Update location settings to control where your ads are served
• Update text guidelines to refine your messaging

Google advises waiting at least 2 weeks after implementing AI Max before making any major campaign changes.

Most of these controls help refine your targeting, but won’t eliminate your IVT exposure. They only apply after AI Max activation (and IVT can proliferate during the 2 week wait). It also takes time to manually implement these controls, and they won’t reduce IVT from search queries that don’t appear in your reports.

To properly control IVT, you need to validate traffic at the source, before the click. This helps maintain incrementality without exposing your campaigns to IVT, keeping your conversion data clean.

That’s where Lunio comes in. Our invalid traffic detection solution identifies and blocks IVT at the source, helping performance marketers get more from automated campaign types like AI Max and Performance Max. Joe Seabridge, paid media manager at Lunio client Represent, said:

"As the marketing sector continues to evolve, more spend is inevitably going to automated campaign types like Performance Max. With less control over where budget actually gets spent, Lunio acts as a guardrail, ensuring we’re feeding higher quality traffic into our campaigns to optimize against higher-intent visitors."

Retail first, not retail only

Much of the AI Max performance data so far is based on retail advertisers, but that doesn’t mean only retail brands are affected. Retail advertisers were among the earliest to adopt AI Max, thanks to the feed-driven, automation-friendly nature of ecommerce.

Other sectors haven’t seen performance problems on quite the same scale — yet. This is likely because sectors that favor tight, regulated, exact match campaigns are less likely to adopt query-expanding features like AI Max.

But lead gen advertisers aren’t exempt. As DSA and other features are sunsetted, many of these advertisers will be pushed over to AI Max automatically. The symptoms of the problem might look different — spam leads rather than limited conversions — but they’ll probably still be there.

Reveal your IVT rate with Lunio

As more research is showing, AI Max tends to prioritize traffic quantity over quality. High reach and impression share can be helpful, but it’s important that you know who’s seeing your ads, and whether these users are worth paying for. That’s why it’s essential to track your IVT rate, especially if you’re using AI Max.

Google and other ad platforms are notoriously bad at tackling IVT. And as they make it increasingly difficult to access performance data, advertisers need as much information as possible to get the best results.

Lunio tells you exactly how much IVT is affecting your AI Max campaigns. It monitors 100% of your traffic and blocks invalid users in real-time, keeping your campaign data clean and preventing wasted ad spend. Plus, Lunio lets you segment your traffic reports by campaign type, so you can monitor AI Max performance independently of standard Search.

Establish your IVT baseline and find out the real cost of invalid traffic for your paid media performance with a free 14-day traffic audit from Lunio.

FAQ

Learn more about how AI Max can affect invalid traffic rates in these frequently asked questions.

Does AI Max increase invalid traffic?

Yes, it appears that AI Max can increase your exposure to invalid traffic. Lunio data indicates a clear correlation between AI Max adoption and invalid traffic, with a significant jump in IVT rates coinciding with AI Max adoption among retail businesses. Additionally, the IVT rate clearly outpaced total click share as AI Max adoption increased.

How much invalid traffic do AI Max campaigns have?

Data from Lunio’s 2026 Global Traffic Report found that, on average, brands experienced a 35% increase in IVT after switching on AI Max for Search.

The exact volume of IVT is brand-specific. The best way to find out your AI Max IVT rate is to get a free traffic audit.

Why would AI Max attract more invalid traffic than standard Search?

AI Max increases your exposure to IVT because it broadens your reach without putting in adequate controls to remove invalid users before the click. So even if your IVT rate remains the same, you’ll be exposed to more invalid users simply by increasing your impression share.

Can negative keywords and URL exclusions fix it?

Not usually. Exclusions like negative keywords and URL exclusions are mostly added reactively, after you’ve seen them crop up in query reports. Post-click exclusions can help reduce exposure after the click, but it won’t undo the damage already done. Allowing invalid users to interact with ads can corrupt your data, leading to a negative feedback loop that invites more invalid users to click your ads.

Does Google refund invalid clicks from AI Max campaigns?

No, but they may issue ad credits that you can put towards future campaigns. Bear in mind that it’s a myth that invalid traffic is taken care of in-platform. In-platform filters are generally good at identifying general IVT, but only detect a small fraction of sophisticated IVT, which is more dangerous and insidious. That’s why third-party click fraud detection platforms are required to protect you from the most harmful types of IVT.

Is AI Max the same as Performance Max?

No. AI Max and Performance Max are two separate campaign types available to Google advertisers. AI Max is specific to Search campaigns, while Performance Max enables automated advertising across a range of Google channels, including Google Display Network, YouTube, Gmail, and Google Maps.

Should I turn AI Max off?

AI Max has plenty of risks, but switching it off altogether probably isn’t the solution. For one thing, Google is pushing more users onto its AI-powered products, so you may be forced into using AI Max sooner or later if you want to keep advertising via Google Search.

So instead of turning off AI Max, it’s best to use best practices to optimize campaigns, and use reliable third-party click fraud prevention platforms to protect your ad spend and campaign hygiene.