For three years ChatGPT enjoyed the rarest prize in tech: its name became the whole category. People did not say they were using generative AI. They said they were using ChatGPT, the same way folks once said they would Google something.
Now it looks like the golden run that began in 2023 may finally be cooling off.
Under half the market for the first time
According to Sensor Tower's new State of AI 2026 report, ChatGPT's slice of the AI assistant market fell below 50% for the first time in March 2026, then closed May at 46%. Over the same stretch Google Gemini holds 28%, and Claude has climbed to 10%.
A TrendKia report in May had already flagged that ChatGPT's web traffic share had slid from 77.6% to 53.7% over a single year. Sensor Tower's figures simply confirm that it has now crossed into minority territory.
Still the biggest app on earth
None of this means ChatGPT is dying. In May the app sailed past 1 billion monthly users, becoming the fastest app in history to reach that milestone, ahead of TikTok, YouTube and Instagram. OpenAI is now reshaping ChatGPT into a superapp that bundles shopping and agents, timed to line up with an IPO process the company has already kicked off.
What is actually ending is the monopoly on being the one AI app that even your most casual relative has heard of. The more rivals show up in the market, the more brand-agnostic everyday consumers become.
Why Gemini is surging
Gemini's rise is mostly a distribution story, and the headcount depends on who is counting. Google told investors in February that Gemini had reached 750 million monthly users, then announced more than 900 million at its developer conference in May. Sensor Tower's outside tracking, which measures only Gemini's own app and site, puts that same month at 662 million.
Either figure lands in the same spot. ChatGPT's dominance is fading not because it has gotten worse, but because distribution and default settings now matter more than raw capability. Gemini's deep integration across Android, Search, Chrome and Workspace hands it an edge that no benchmark can capture.
Claude's trust dividend
In the U.S., Claude's share nearly tripled, from 5% in December to 14% in May, and that jump has a clear story behind it. In late February, Anthropic refused Pentagon demands to drop safeguards against mass surveillance and autonomous weapons. The Department of Defense, since renamed the Department of War, branded the company a supply chain risk. Days later, OpenAI signed its own deal with that same department.
Sensor Tower found that ChatGPT uninstalls in the U.S. spiked roughly 200% above average during the week of March 9. For five straight days that March, Claude out-downloaded ChatGPT before ChatGPT's lead snapped back. Brand trust, it turns out, is a feature too.
Crypto traders have a clear favorite, and it is not ChatGPT
The juiciest detail sits inside the user-persona data. Grok users are about four times more likely than the general population to be crypto traders, the widest skew of any assistant Sensor Tower measured.
For whatever reason, ChatGPT is a meh choice among degens. Claude sits a distant second, ahead of Copilot, while ChatGPT users barely clear the population baseline.
Grok's advantage traces back to X, where it ships free inside Premium and reads live posts the moment a meme coin starts trending, an edge no standalone chatbot can match.
Several structural factors reinforce one another here. Grok is embedded in X's ecosystem, where crypto traders already gather; it taps straight into real-time sentiment and meme coin chatter; Musk's personal crypto enthusiasm shapes the platform's culture; and the user base itself leans toward people already steeped in crypto Twitter. Together these create a self-reinforcing loop that naturally pulls Grok toward crypto-focused output.
Depending on the situation, it also offers an experience much like ChatGPT, with a chat box, artifacts, coding abilities, generative image, generative video that ChatGPT does not offer, web searching, connectors and more.
Claude's runner-up spot lines up with last fall's Alpha Arena contest, where Grok and Claude Sonnet posted real-money trading gains on the Hyperliquid exchange while GPT-5 and Gemini 2.5 Pro each lost more than a quarter of their stake. Crypto Twitter remembers who made it money, so its chatbot preferences may not be so crazy after all.
The money says the same thing
The revenue numbers back up the user numbers. Claude's average revenue per U.S. mobile user jumped from under $0.50 last September to $2.76 in May, ahead of ChatGPT's $1.74, and 13% of Claude's users now pay for a subscription, the highest conversion rate in the report. OpenAI is marching toward an IPO with the largest audience in AI history and a shrinking claim on what that audience actually prefers.
