For the first time, ChatGPT’s dominance of the generative-AI assistant market has wobbled. According to the “State of AI 2026” report that research firm Sensor Tower released on June 16, ChatGPT’s share by true-user count slipped below 50% for the first time in March this year and fell to 46.4% by the end of May. Google Gemini and Anthropic Claude have moved quickly to fill the gap, and the market is shifting from a single front-runner toward several rivals jostling for position. Below, we look at how the share landscape changed and what is driving it. 🤖

TL;DR

  • ChatGPT’s share fell to 46.4% by late May — below 50% for the first time (Sensor Tower).
  • Gemini reached 27.7% (about 662M MAU) and Claude 10.3% (about 245M MAU).
  • ChatGPT still leads with more than 1.1 billion MAU, though its share is sliding.
  • The market is moving from a “single leader” toward “multipolar competition,” with users switching between services.

📉 How far did ChatGPT’s share fall?

The core point is that ChatGPT gave up its majority share for the first time. In Sensor Tower’s tally, ChatGPT’s “True Audience” share dropped below 50% for the first time in March 2026 and stood at 46.4% by the end of May. A figure that was still above 50% at the start of the year fell below half in just a few months.

That said, a smaller share does not mean ChatGPT has been pushed aside. Its monthly active users (MAU) still top 1.1 billion, holding the global No. 1 spot. With the overall market expanding fast and challengers growing even faster, it is closer to the leader’s share being trimmed in relative terms.

🥈 How far have Gemini and Claude come?

The chase is led by Google Gemini and Anthropic Claude. In Sensor Tower’s count, Gemini ranked second with a 27.7% share (about 662 million MAU), and Claude third with 10.3% (about 245 million MAU). The rest — Grok, Perplexity, DeepSeek, Meta AI and others — each came in below 5%.

Claude’s growth stands out in particular. According to the report, Claude’s true users were up 452% year over year as of May, and its U.S. market share climbed from 4.4% to around 14% over the same period. Gemini appears to have grown by leaning on integration across Google’s ecosystem — Search, Android and Workspace — while Claude has drawn users on the strength of work-productivity areas such as coding and documents.

🔀 How is the market structure changing?

The most visible change is that users no longer stick to a single service. As competition has intensified, the same user increasingly switches among several AI assistants depending on the task. It signals a market moving from a “single leader” toward “multipolar competition.”

Even so, market concentration remains high. Sensor Tower found that in the first quarter, three services — ChatGPT, Gemini and DeepSeek — accounted for roughly 90% of all time spent in AI assistant apps. Rather than a crowd of services, it looks more like a handful of strong players competing and reshuffling rankings among themselves.

📝 The bottom line

The generative-AI assistant market sits at a turning point, moving from ChatGPT’s solo run toward multipolar competition. ChatGPT still leads with 1.1 billion MAU, but its share broke below half for the first time at 46.4% in late May, with Gemini (27.7%) and Claude (10.3%) closing the gap fast. Still, the combined share of the top few services remains high, so the market looks less like a crowded field than a contest among a few strong players. Worth watching from here: whether challengers sustain their growth, how far user switching and parallel use spread, and where the monetization race heads.

※ This article is for informational purposes only and is not investment advice.

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