TL;DR
- Adthena counted 7,306 weekly ChatGPT advertisers in the week of 9 July 2026 and 12,075 in the week of 31 August, with a peak of 13,009 in the week of 10 August.
- One-to-two word queries produced 62.9% of 288.6 million US AI Overview ad appearances and 74.4% of 13.6 million in Asia, per Adthena's September 2026 pulse.
- The result reverses Adthena's April and June 2026 reports, which found three-to-four word queries drove most AI Overview ad appearances; no cause is given.
- The September advertiser count does not state its market scope, and ChatGPT ads launched in Thailand on 23 September 2026, after the 31 August window closed.
Adthena's September 2026 AI data pulse, published on 25 September 2026, reports that the weekly number of unique advertisers in ChatGPT ads rose from 7,306 in the week of 9 July to 12,075 in the week of 31 August, an increase of roughly 65 percent. The same report finds that one-to-two word searches now produce more than half of all ad appearances inside Google's AI Overviews in every region Adthena measured, the opposite of what the company itself reported in April and June 2026.
What Adthena's September pulse reports
Adthena is a search intelligence company that sells ad-monitoring data, so its reports are vendor research rather than platform figures. According to PPC Land's coverage of the report, the September pulse is an eight-page document sent to press and summarised in a LinkedIn post by the company. It covers three things: ChatGPT advertiser participation, the length of queries that trigger ads inside Google AI Overviews, and which brands capture AI Overview ad visibility in the United States, the European Union, Australia and Asia.
ChatGPT advertiser count, week by week
Adthena tracked unique advertisers appearing in ChatGPT ads each week between 9 July and 31 August 2026. The count started at 7,306 in the week of 9 July, peaked at 13,009 in the week of 10 August, dipped to just over 10,000 in the week of 24 August, and closed at 12,075 in the week of 31 August. Adthena describes the full rise from its lowest recorded week to its highest as a 1.78 times increase, and the start-to-end change as roughly 65 percent.
Adthena's materials do not explain the dip. PPC Land notes that it falls just before ChatGPT ads went live in 31 European markets on 24 August 2026, and that the recovery follows the days after that expansion. Adthena itself does not draw a causal link, so the timing is a coincidence worth noting, not a finding.
Short queries now lead AI Overview ads
The second finding concerns Google, not OpenAI. Adthena reports that one-to-two word queries now account for over half of AI Overview ad appearances in every market it measured. The regional split below is taken from Adthena's report as quoted by PPC Land.
| Region | Total AI Overview ad appearances | Share from 1-2 word queries |
|---|---|---|
| United States | 288.6 million | 62.9% |
| European Union | 110.8 million | 62.4% |
| Australia | 50.5 million | 56.5% |
| Asia | 13.6 million | 74.4% |
Three-to-four word queries sit in second place: 33.1 percent in the United States, 34.3 percent in the EU, 39.6 percent in Australia and 23.9 percent in Asia. Queries of five words or more account for less than 5 percent of appearances in every region, and seven-plus word queries are 0.4 percent or less.
What is new compared with Adthena's earlier reports
Relevant Audience covered Adthena's August pulse on 25 August 2026 in "Retail took 39% of ChatGPT ads on 24% of US queries, Adthena finds", which looked at category concentration during the early European launch. The September data moves the story on in two ways.
First, it adds a trend line. Adthena's earlier index, launched in July 2026, counted 7,378 distinct ChatGPT advertisers across the United States, the United Kingdom and Australia for the single week of 13 to 20 July. The September pulse starts almost exactly at that level and shows eight weeks of movement after it. PPC Land points out that the September pulse does not say whether its 7,306-to-12,075 figures use the same three-market scope or a broader set of regions. That matters, because ChatGPT ads were adding markets during the window, and a count that grows partly because more countries are included measures something different from a count that grows within fixed markets.
Second, the query-length result reverses Adthena's own earlier conclusion. In April 2026 the company published a 29 million query report finding that three-to-four word queries accounted for over 60 percent of AI Overview ad appearances, which it presented as a challenge to the idea that AI search is mainly a long-tail phenomenon. A June 2026 Adthena report put the three-to-four word band at between 57.4 and 71.2 percent across three markets. The September pulse now puts one-to-two word queries on top everywhere.
Why the reversal happened is not stated
Adthena describes the September result as a shift from June. PPC Land reports that the documents it reviewed do not explain the mechanism. Three explanations are possible and none is confirmed by the source: Google may have changed which queries are eligible for AI Overview ads, the mix of queries reaching AI Overviews may have changed, or Adthena's measurement method may differ between the two periods. PPC Land also notes that Google's search chief Liz Reid said in April 2026 that longer natural-language queries were already happening at scale, and that ads appeared in 0.12 percent of AI Overviews by April 2026, up from 0.052 percent in November 2025. Her comments concerned overall query behaviour and ad frequency, not the word-count split of ad appearances, so they neither confirm nor contradict the September data.
Which brands lead AI Overview ads by region
Adthena's report also ranks the advertisers with the largest share of AI Overview ad appearances in each region. Carvana leads the United States at 1.2 percent, Booking.com leads the EU at 2.9 percent, Dan Murphy's leads Australia at 4.3 percent and Hostinger leads Asia at 3.6 percent. The Asian top six also includes Shopee Singapore at 3.1 percent, Lenovo at 3.1 percent, Shopee Indonesia at 2.9 percent, Booking.com at 2.8 percent and Trip.com at 2.8 percent.
According to Adthena, Booking.com is the only brand in the top five across three markets at once: the United States, the EU and Asia. Adthena summarises the rest of the data by saying that every other category belongs to whoever owns the local market. The shares are small in absolute terms. A leading advertiser in the United States holds just over 1 percent of appearances, which suggests AI Overview ad visibility is spread across many advertisers rather than concentrated in a few.
Retail sub-verticals, measured by clicks
For two retail sub-verticals Adthena measures share of clicks rather than AI Overview appearances. In electronics and appliances, Temu leads the United States at 28.3 percent and Australia at 14.25 percent, and places third in the United Kingdom at 7.89 percent behind Argos at 17.97 percent and Amazon UK at 12.0 percent. In apparel and accessories no brand passes 9 percent in any market: Lululemon leads the United States at 8.8 percent, Shein leads the UK at 4.66 percent and Coach leads Australia at 7.96 percent. Adthena's reading is that apparel has no global winner, only local leaders.
Limits of the data
These figures deserve careful handling, and the source itself flags several limits.
- The ChatGPT count measures unique advertisers seen, not spend, impressions or results. Adthena's method, as PPC Land describes it, monitors paid placements across live ChatGPT sessions rather than drawing on OpenAI's internal reporting.
- The market scope of the September advertiser count is not specified, as noted above.
- No independently audited share-of-voice standard exists for ChatGPT ads yet, according to PPC Land. OpenAI's own Ads Manager reports cost-per-click, impressions and click-through rate for an advertiser's own campaigns but gives no market-wide view, which is the gap vendors such as Adthena sell into.
- Adthena has commercial interests in this channel. PPC Land notes its July 2026 partnership with Dentsu to measure UK ChatGPT cost-per-click volatility, an arrangement PPC Land examined critically at the time.
- Adthena has now published at least three query-length reports in about five months, and the latest contradicts the two before it without explaining why.
None of that makes the data useless. It means the direction of travel is more reliable than any single figure, and a claim built on one Adthena number should say where the number came from.
The expansion behind the advertiser growth
The advertiser rise happened while ChatGPT ads were expanding quickly. PPC Land's timeline says OpenAI began serving ads on 9 February 2026 to logged-in adult users on the Free and Go tiers in the United States. Brazil and Mexico went live on 17 August 2026, bringing the publicly counted total to nine markets. Ads reached 31 European markets on 24 August, India followed on 29 August, and on 31 August OpenAI said ChatGPT ads operated in more than 40 countries. The same week, according to CNBC reporting cited by PPC Land, OpenAI said advertising had reached a $1 billion annualised revenue run rate. Seven more Asian markets were added after Adthena's window closed, taking the count past 60 countries by late September.
ChatGPT ads went live in Thailand on 23 September 2026, as Relevant Audience reported on 24 September. That date is after Adthena's measurement window ended on 31 August, so Thai advertisers cannot be part of the September advertiser count. PPC Land's report does not name Thailand among the seven Asian markets it mentions.
What advertisers should take from it
For Google Ads accounts, the query-length finding is the more actionable part, with the caveat that it has already flipped once. If short, high-intent terms now drive most AI Overview ad appearances, advertisers who trimmed short-tail coverage in favour of mid-length terms after the April and June reports may want to check their own data before changing anything again. Search term reports in Google Ads will show which query lengths actually trigger your ads; a vendor's regional average cannot. Google does not break out AI Overview placements in a way the source describes, so this remains a question of reading your own query data.
For ChatGPT ads, a growing advertiser count points to more competition in each auction as new markets open, though the source gives no price data to confirm that. On the organic side, the same shift explains why brands are paying attention to how they are cited inside AI answers, which is the work covered by ChatGPT SEO and broader generative engine optimisation.
What this means for Thai marketers
Adthena's report does not mention Thailand. Its Asian AI Overview figures cover 13.6 million ad appearances with 74.4 percent from one-to-two word queries, the highest short-query share of the four regions, but the source does not say which Asian countries are included. Thai advertisers should treat the Asia number as regional context, not a Thai benchmark. The more practical point is timing: ChatGPT ads have been available in Thailand only since 23 September 2026, so Thai brands are entering a channel where, going by Adthena's counts, more than 12,000 advertisers a week were already active in other markets by the end of August. Early Thai campaigns will have little local benchmark data, which makes careful tracking from day one more useful than copying overseas averages.
FAQ
How many advertisers are running ChatGPT ads?
Adthena counted 12,075 unique advertisers in ChatGPT ads in the week of 31 August 2026, up from 7,306 in the week of 9 July. The count peaked at 13,009 in the week of 10 August, and the report does not state which markets it covers.
Do short keywords or long queries trigger more AI Overview ads?
Short ones, according to Adthena's September 2026 data: one-to-two word queries produced 56.5 to 74.4 percent of AI Overview ad appearances across the four regions measured. That reverses Adthena's April and June 2026 reports, which found three-to-four word queries dominant.
Why did Adthena's query-length finding change?
The source does not say. PPC Land reports that neither Google's ad-serving changes nor any change in Adthena's methodology is identified as the cause.
Is Thailand included in Adthena's September data?
No Thai data is identified in the report. ChatGPT ads launched in Thailand on 23 September 2026, after the 31 August end of Adthena's advertiser window, and the report's Asia figures are not broken out by country.
Can I rely on Adthena's numbers for planning?
Use them as directional context rather than a benchmark. They come from a vendor's own monitoring of live sessions, measure advertiser counts and appearances rather than spend or results, and have reversed once on query length within five months.
Next step
If you are deciding how to split budget between Google search, AI Overview visibility and the new ChatGPT ads inventory in Thailand, start with your own query and conversion data. Relevant Audience's Google Ads team can help you read it before the next vendor report changes the picture again.
