Search advertising intelligence firm Adthena reports that advertisers on ChatGPT grew 65% while queries producing Google AI Overviews declined, according to data the firm shared with PPC Land.

The inverse trend — rising paid adoption on OpenAI's chatbot platform and shrinking query volume on Google's AI-generated answer surfaces — comes as brands reassess where to place search budgets in 2025.

What did Adthena measure?

Adthena, a competitive search-intelligence platform used by agencies and in-house PPC teams, tracks paid-search activity across major surfaces. According to the firm's findings reported by PPC Land, the advertiser count on ChatGPT climbed 65% over the period studied. Over the same window, query volume that surfaces Google's AI Overviews — the AI-generated summaries that appear above traditional blue links — moved in the opposite direction.

The report frames the two trends as complementary: budget and attention are not just shifting between Google surfaces but across the broader generative-AI search ecosystem, including conversational interfaces where ads now appear inside chat responses.

Why would ChatGPT gain advertisers while AI Overviews lose queries?

The two movements may share a common cause. Marketers spent 2024 testing placements on emerging AI surfaces, and ChatGPT's ad inventory has expanded as OpenAI pushed further into monetization. At the same time, user behavior on Google's AI Overviews has shown signs of query-level fatigue: fewer searches trigger the AI summary, which shrinks the pool of impressions above the organic fold.

Search watchers have noted for months that AI Overview appearance rates vary sharply by query category, with informational queries over-represented and transactional queries under-represented. If transaction-heavy queries — the ones advertisers most want to bid on — produce AI Overviews less often, then a query-volume decline could matter less to paid media than to organic SEO.

How should advertisers read the gap?

For paid-search teams, the Adthena numbers suggest three practical readings:

• ChatGPT ad inventory is no longer experimental. A 65% rise in advertiser count signals a market in active onboarding, not a pilot phase.
• AI Overview query shrinkage reduces one of the biggest unknowns in 2025 Google Ads planning: how often an ad competes against an AI answer rather than another advertiser's listing.
• The two trends together imply budget reallocation, with some search spend shifting away from Google's AI surfaces and toward OpenAI's conversational placements.

For SEO teams, the AI Overview query decline is the more consequential signal. If Google is showing fewer AI Overviews on the queries that matter most to a site, the threat model that animated 2024 — "AI Overviews eat our clicks" — may be recalibrating faster than the wider industry discussion suggests.

What's still unclear?

Adthena has not published the specific comparison window, the advertiser-count methodology, or how it counted "AI Overview queries" — whether impressions, search-trigger counts, or another metric. Without those definitions, search marketers should treat the 65% figure as directional rather than absolute.

The PPC Land report does not include a direct quote from Adthena or OpenAI, and Google has not publicly addressed the AI Overview query trend inside this dataset. That absence matters: distinguishing Adthena's tool-derived measurement from any official Google or OpenAI disclosure will determine how much weight to give the figures.

What to monitor next

Three signals in the coming weeks and months will determine whether Adthena's snapshot holds up:

1. Adthena's next quarterly read on advertiser count across ChatGPT and competing AI surfaces, which will confirm whether the 65% growth curve continues or flattens.
2. Any Google disclosure — in earnings calls, blog posts, or Search Central updates — of AI Overview impression share or appearance rate at the query level.
3. OpenAI's expansion of ad formats, placement density, and targeting controls inside ChatGPT, each of which extends or caps the runway behind the 65% growth.

For now, the headline finding is simple and worth watching: Adthena's data points to a search-ad market that is splitting, not shrinking, with OpenAI's chatbot taking on more advertisers while Google's AI Overview surface quietly contracts.