ChatGPT is still the world’s biggest AI assistant, but its lead is no longer as solitary as it looked during the first wave of consumer AI adoption.
Sensor Tower’s State of AI 2026 report, released June 16, says ChatGPT’s “True Audience” share fell below 50% for the first time in March 2026, using a cross-platform measure of unique users across mobile apps and the web. TechCrunch, citing the same report, reported that ChatGPT ended May at 46.4% share, followed by Google Gemini at 27.7% and Anthropic’s Claude at 10.3%.
That is not a collapse. Sensor Tower also says ChatGPT became the fastest mobile app to reach one billion monthly active users in May 2026, reaching the milestone roughly three years after launch. The more important change is that the market around it is starting to behave less like a single-product rush and more like an app category with several defaults, each strong in different contexts.
The AI assistant market is growing and fragmenting at the same time
Sensor Tower estimates that global time spent in generative AI apps will rise from 17.2 billion hours in the first half of 2025 to 36 billion hours in the first half of 2026. It also expects global in-app purchase revenue from AI apps to top $4 billion in the first half of this year, up 36% from the second half of 2025.
Those numbers make the share shift more interesting. ChatGPT can keep growing in absolute users while losing share because the category around it is expanding quickly. Gemini benefits from Google’s distribution through Android, Search, Workspace, and the Gemini app. Claude has built a strong productivity and coding reputation, especially on the web and among paid users. DeepSeek, Grok, Perplexity, Meta AI, Copilot, and other assistants still trail the leaders by Sensor Tower’s share measure, but they add to the sense that many users are no longer treating one assistant as enough.
A16z’s latest Top 100 Gen AI Consumer Apps report described similar “multi-tenanting” behavior earlier this year, estimating that roughly 20% of weekly ChatGPT web users were also using Gemini in the same week. That pattern matters because AI assistants are not interchangeable search boxes once people start connecting files, calendars, inboxes, coding environments, shopping accounts, and workplace tools.
Why Gemini and Claude are gaining ground
Gemini’s growth is partly a distribution story. Google has been threading AI across products that already shape internet behavior. At I/O 2026, Google said AI Mode had surpassed one billion monthly users, that Gemini 3.5 Flash would become the default model for AI Search, and that a seamless Search experience would let people move from AI Overviews into follow-up AI Mode conversations. Google is also preparing more agent-like Search features, including information agents and AI-generated mini apps for ongoing tasks.
That gives Gemini a different growth path from ChatGPT. Instead of asking every user to open a standalone AI app, Google can put AI into search, shopping, productivity, Android, YouTube, Gmail, and developer tools. For consumers, that can make Gemini feel less like a destination and more like a layer inside products they already use.
Claude’s path is narrower but commercially important. Sensor Tower says Claude’s U.S. True Audience share has more than tripled, led by web usage, and TechCrunch reported that Claude’s mobile average revenue per user in the United States rose sharply from September 2025 to May 2026. That suggests Claude is winning fewer casual users than ChatGPT or Gemini, but attracting people willing to pay for writing, analysis, coding, research, and workflow help.
The distinction is useful for understanding the market. ChatGPT is the broad consumer default, Gemini is the ecosystem challenger, and Claude is increasingly the premium productivity assistant. Those positions can overlap, but they point to different businesses and different kinds of user loyalty.
AI is becoming a discovery layer, not just a chatbot category
The report also ties assistant growth to a broader shift in how people find information and make buying decisions. Sensor Tower says generative AI websites generated more than 67 billion visits and about 23 billion hours in the first quarter of 2026, while AI assistant web traffic became one of the fastest-growing online categories.
In a separate State of Web 2026 analysis, Sensor Tower argued that AI assistants are emerging as a new discovery layer alongside search and social. It noted that ChatGPT added more than 60 billion visits year over year and became the sixth most visited website worldwide, while Gemini, Claude, DeepSeek, and Grok also ranked among breakout sites by traffic and time spent.
The commercial implications are already visible. Sensor Tower says generative AI referrals to shopping websites increased across every major retail category between the fourth quarter of 2024 and the first quarter of 2026. It also says Amazon shoppers using Rufus, Amazon’s AI shopping assistant, convert at nearly twice the rate of non-users. AI-themed digital ad spend in the U.S. reached $1.3 billion from January through May 2026, up 48% year over year.
For publishers, retailers, software companies, and app developers, that means AI assistant share is not just a vanity metric. If more people begin product research, troubleshooting, travel planning, coding help, or news discovery inside assistants, the competitive map affects who gets surfaced, cited, linked, summarized, or bypassed.
What users and companies should take from the shift
For normal users, the practical answer is not to chase every new AI app. It is to recognize that different assistants now have different strengths. ChatGPT remains the safest starting point for general-purpose help and broad app support. Gemini is becoming harder to ignore for search-heavy tasks, Google account context, Android workflows, and multimodal work tied to Google’s ecosystem. Claude is often strongest where long documents, coding, editing, and structured workplace reasoning matter.
For companies, the lesson is sharper: building around one AI assistant is starting to look risky. Customer acquisition, support, search visibility, internal productivity, and shopping journeys may all pass through several AI interfaces. A brand that only watches ChatGPT referrals, or only optimizes content for Google Search, may miss how users are moving across assistant apps and browser-based AI tools.
The market is still concentrated. Sensor Tower says ChatGPT, DeepSeek, and Gemini accounted for nearly 90% of total time spent across AI assistant apps in the first quarter of 2026. But concentration does not mean stability. The rise of Gemini and Claude shows that distribution, trust, workflow depth, model quality, pricing, and user values can all move share even while the overall market grows.
ChatGPT’s sub-50% share is therefore less a sign that OpenAI is losing the AI race than a sign that the race has changed. Consumer AI is becoming a multi-app market, and the next advantage may come from being the assistant people keep connected to their work, shopping, search, devices, and daily routines.
