What happened
Similarweb published its 2026 Generative AI Landscape report on July 29, documenting a year of redistribution in generative AI web traffic. ChatGPT's worldwide share fell from 76.4% in June 2025 to roughly 53% by May 2026, a drop of more than 20 percentage points in twelve months. Gemini absorbed most of that loss, rising from under 9% to roughly 27-28% of traffic, a trajectory riding Google's existing distribution across Search, Android, and Workspace. Claude posted the steepest proportional gain of any platform tracked, climbing from under 2% to close to 9%, making it the fastest-growing assistant in the category. The category itself kept expanding fast enough to make any single platform's slice look smaller: average monthly visits across generative AI platforms grew 70% year-over-year to 9.5 billion. ChatGPT's absolute traffic held roughly flat throughout the period. It simply stopped being the whole market.
Why AI traffic share concentration is breaking apart
MagnetizeX builds founder visibility systems for B2B firms.
Founders who built their AI visibility work around ChatGPT alone are now optimizing for roughly half the audience, and that fraction keeps shrinking every quarter. Gemini's growth rides distribution Google already owns, which means it scales as fast as Google chooses to push it into existing products people open daily. Claude's growth comes from developers and technically sophisticated buyers opting in deliberately, a smaller audience that tends to stick around once it commits to a workflow. Both platforms are now large enough that skipping either one leaves real pipeline on the table, particularly for B2B software with a technical or developer-adjacent buyer persona who researches purchases inside these tools directly.
- Audit where your brand shows up beyond ChatGPTRun the same brand and product queries through Gemini and Claude, not just ChatGPT. Similarweb's data shows citation sets change roughly monthly and barely overlap between platforms, so a mention in one doesn't predict a mention in another, and a single-platform check will miss real gaps.
- Weight content toward checkable, comparable claimsCitation rates run three to five times higher in categories built on comparable facts, like travel and automotive, than in advice-heavy categories like professional services. Specific numbers, named comparisons, and dated claims get cited noticeably more often than general guidance or broad opinion pieces.
- Watch homepage and direct traffic for hidden AI referralsChatGPT's May 2026 update pushed homepage referrals from roughly 28% to over 60% of its referral traffic, and that level has held rather than faded. Traffic your analytics logs as direct or unattributed may increasingly be AI-driven discovery with the referral source stripped out entirely.
By the numbers: Citation presence in US ChatGPT prompts rose from 1.6% in June 2025 to 6.8% by May 2026, and roughly 26% of ChatGPT responses now contain an ad, concentrated most heavily in a session's very first reply before tapering off.
"What this data doesn't show is intent quality by platform. Traffic share tells you where people go, it doesn't tell you what they're asking, how deep into the purchase journey they are, or which platform is driving the most commercial outcomes," said Ofir Halfon, a global partnerships and GTM leader, commenting publicly on Similarweb's traffic data.
What to do this week
Pull your last 90 days of ChatGPT-referral traffic in GA4, then run the same set of five branded and category prompts through Gemini and Claude manually this week. If your product isn't surfacing in at least one of the two, add a comparison page or a specific-numbers FAQ, the content type Similarweb's data says gets cited most often.