ChatGPT's AI Search Share Halves in a Year: What Now?

ChatGPT's share of worldwide generative AI web traffic has fallen from roughly 76% in June 2025 to around 53% by May 2026, according to Similarweb's 2026 Generative AI Landscape report. Gemini has climbed past a quarter of all traffic and Claude has become the fastest-growing platform in the category. For brands doing GEO work, this means optimising for ChatGPT alone no longer reaches most of the AI-using audience, so visibility strategy has to become genuinely multi-platform.

What changed?

Similarweb published its 2026 Generative AI Landscape report this week, and the headline number is stark. The report documents a market where ChatGPT's share of standalone web visits has fallen sharply since mid-2024, while advertising has moved from experiment to fixture, appearing in 26% of US desktop ChatGPT chats during June 2026.

The scale of the shift is significant. ChatGPT remains the largest standalone generative AI website by monthly visits, but its share of the category has eroded steadily, holding above 80% of the tracked set through late 2024, then declining across 2025 and into 2026 to just above 50% by May 2026. Gemini, Claude, Perplexity and DeepSeek absorbed the difference, according to FourWeekMBA's analysis.

Other trackers using the same Similarweb panel confirm the trend with more granular numbers. ChatGPT's share of AI chatbot web traffic dropped from 79.0% in May 2025 to 53.9% in May 2026, while Gemini rose to 27.9% and Claude reached 9.2%, per CommandLinux's usage statistics. A separate June 2026 update from PPC Land put it even more directly: ChatGPT lost 23.7 points over 12 months while Claude surged from 1.6% to 8.9% and Gemini captured 27.3% of AI traffic.

Claude's trajectory is the standout. Anthropic's Claude reached approximately 9.2% in June 2026, up from just around 2.2% six months earlier, PPC Land reports. That is not just a consumer story either: Anthropic's commercial position has strengthened alongside its traffic growth.

The other new wrinkle in the report is advertising inside AI answers. Similarweb found that roughly 26% of ChatGPT responses now contain an ad, with ad density concentrated most heavily in the first response of a session. That is a meaningful change to how a ChatGPT answer looks and behaves, and it adds a new variable to how brands get seen at all.

Why does this matter for your business?

The core implication is simple: the days of treating "AI search" as synonymous with "ChatGPT" are over. As Similarweb's own analysis puts it, for three and a half years "ChatGPT" was practically shorthand for generative AI, but that is no longer true, with Gemini having climbed past a quarter of all traffic and Claude gone from a rounding error to the fastest-growing platform in the category.

That has direct consequences for how marketing teams should think about brand visibility. Optimising for one AI platform used to cover most of the addressable audience, but it no longer does. A GEO strategy tuned exclusively to how ChatGPT cites and describes brands is now missing more than four in ten AI-driven interactions.

It is also worth noting that overall usage of AI platforms is still expanding fast, even as ChatGPT's relative share shrinks. Average monthly web visits to generative AI platforms reached 9.5 billion between June 2025 and May 2026, up 70% from 5.6 billion in the preceding twelve months, according to Similarweb. In other words, this is not a shrinking pie being redistributed, it is a growing pie where ChatGPT's slice is proportionally smaller even as its absolute traffic holds broadly steady.

Gemini's rise deserves particular attention because of where its traffic is coming from. Gemini holds 27.9% of global AI chatbot web traffic in May 2026, with the Gemini app passing 900 million monthly active users, up from 400 million a year earlier, per CommandLinux. Google's distribution advantage through Search, Android and Workspace means Gemini exposure often happens without users actively choosing it, which is a very different discovery path from a deliberate ChatGPT query.

Claude's growth is smaller in absolute traffic but strategically important because of where it is concentrated. Claude posted the fastest recent growth on both web traffic and US mobile share, and it leads the enterprise API and coding markets outright, according to FourWeekMBA. If your brand sells into technical or enterprise buyers, Claude citations may matter more than raw traffic share suggests.

The ad penetration figure matters too, because it changes what a citation or mention competes against. If a quarter of ChatGPT responses now carry an ad, brand visibility inside the organic answer has to work harder to stand out from paid placements sitting alongside it.

What should you do now?

First, stop measuring AI visibility on a single platform. If your current GEO tracking only covers ChatGPT, you are missing well over 40% of the addressable AI search audience based on these traffic figures, and that gap keeps widening as Gemini and Claude grow.

Second, treat Gemini as a distribution channel, not just another chatbot. Given its integration inside Google Search, Android and Workspace, brands that already invest in traditional SEO fundamentals, structured data, clear entity signals and authoritative third-party mentions, are likely to see some of that work carry over into Gemini's answers.

Third, if you sell into technical, developer or enterprise audiences, do not ignore Claude on the basis of its smaller consumer traffic share. Its growth is concentrated exactly where B2B buying research happens.

Fourth, keep an eye on how ads inside AI answers evolve. As paid placements become more common inside ChatGPT responses, the line between earned AI visibility and bought AI visibility will blur, and knowing which one you are actually getting will matter more for reporting accurately to leadership.

Finally, this is a good moment to actually check where your brand shows up today rather than assume. Running your brand through a free tool like Sited's AI visibility audit will show you which platforms mention or cite you and which ones do not, which is the first step before deciding where to invest.

Frequently asked questions

Has ChatGPT actually lost users, or just market share?

Its share has fallen, but its user base has kept growing in absolute terms. ChatGPT remains the largest standalone generative AI website by monthly visits, but its share of the category has eroded steadily as the overall market expanded faster than ChatGPT alone could capture.

Why is Gemini growing so quickly?

Much of it comes down to distribution rather than users switching preference. The Gemini app passed 900 million monthly active users, up from 400 million a year earlier, largely through integration across Google's existing products such as Search, Android and Workspace.

Is Claude relevant if it only has around 9% of web traffic?

Yes, particularly for B2B and technical audiences. Claude posted the fastest recent growth on both web traffic and US mobile share, and it leads the enterprise API and coding markets outright.

Do ads inside ChatGPT responses affect brand citations?

They add a new competitive layer. Roughly 26% of ChatGPT responses now contain an ad, with ad density concentrated most heavily in the first response of a session, meaning organic brand mentions now sit alongside paid placements more often than before.

What's the single biggest takeaway for a marketing team?

Multi-platform measurement is no longer optional. Gemini now holds roughly a quarter of worldwide AI web traffic and Claude is approaching one-tenth, meaning a strategy that only accounts for ChatGPT no longer reaches the majority of the AI-using audience on its own.