For more than three years, one app sat at the center of the biggest technology shift of a generation.
It launched in November 2022, created a category almost overnight, and held a majority of global AI assistant market share every single month that followed.
Then, in March 2026, something changed for the first time.
The number that defined a technology era
In November 2022, ChatGPT launched and created the modern AI assistant category.
For over three years, it held a majority of global AI assistant market share.
In March 2026, that ended.
The market had been shifting for months, but March was when the data crossed the threshold that nobody in the industry had seen before.
Sensor Tower, a leading provider of data on the digital economy, released its State of AI 2026 report in June, delivering a comprehensive look at explosive growth in engagement, spending, and advertising on generative AI across mobile apps and the web.
The report reveals that global time spent on generative AI apps is projected to more than double year over year in H1 2026, climbing from 17.2 billion hours in H1 2025 to 36 billion hours.
A market growing in every direction at once
In the first half of 2026, people are on pace to download nearly 2.3 billion AI apps, with total user spending projected to exceed $4 billion, according to Sensor Tower estimates.
That is not a market in trouble.
That is a market fracturing into competition fast enough that even the dominant player is watching its slice shrink while its user count keeps rising.
ChatGPT became the fastest mobile app ever to reach one billion monthly active users in May 2026, achieving the milestone in just three years, faster than TikTok, YouTube, and Instagram.
Reaching a billion users and losing your majority at the same time is not a contradiction.
It means the rest of the market is simply growing faster.
Two challengers moving in completely different ways
The two platforms eating into that majority are taking opposite routes to get there.
Gemini’s momentum is largely due to its integration with Google’s broader ecosystem of tools, while Anthropic’s Claude has gained a strong reputation for productivity use cases.
Sensor Tower put Gemini at 27.7% of the global app market, with 662 million monthly users.
Claude is doing something different.
Claude has experienced explosive growth, led by a strong web presence, and its True Audience share in the US has more than tripled.
That kind of growth rate in a market this size is unusual by any measure.
It also happens to be happening almost entirely in enterprise software, which is where the real money moves.
ChatGPT’s share finally fell below 50%, and the enterprise race now looks nothing like the consumer one
ChatGPT’s True Audience market share, which measures unique users across mobile app and web, fell below 50% for the first time in March 2026. By the end of May 2026 it stood at 46.4%, with Gemini at 27.7% and Claude at 10.3%, according to Sensor Tower’s State of AI 2026.
The chatbot still remains the most popular AI assistant worldwide with over 1.1 billion monthly users, followed by Gemini with 662 million and Claude with 245 million.
But the enterprise numbers tell a sharper story.
Anthropic’s revenue is driven predominantly by enterprise and API customers, with approximately 70, 75% coming from API consumption, enterprises and developers paying per token for Claude model access through direct API, AWS Bedrock, and Google Cloud Vertex AI, rather than mass consumer reach, which is where Anthropic has placed its bets.
At $47 billion ARR as of mid-May 2026, Anthropic reported its revenue run rate alongside its Series H announcement, per CNBC’s reporting, ahead of OpenAI’s $25 billion ARR reached by February 2026, despite having a fraction of ChatGPT’s consumer user base.
For anyone tracking where this open-source coding movement is heading next, the enterprise split between Claude and ChatGPT is the number worth watching.
What the fractured market means for every app on your phone
Sensor Tower’s State of AI report also found that users are increasingly willing to switch between assistants.
OpenAI’s deal with the U.S. Department of Defense on February 28 triggered a 295% day-over-day spike in U.S. app uninstalls, and ChatGPT’s U.S. downloads dropped 13% the same day, suggesting brand trust and values alignment matter to users, not just features.
That is a meaningful shift.
When users switch AI tools over brand values, not benchmarks, the competitive dynamic stops being purely technical.
Analysts point to three main factors driving the change: Google’s Gemini gaining share through default placement on Android and Workspace, Anthropic’s Claude winning an outsized share of enterprise deals, and improving model quality among competitors narrowing the performance gap that once made ChatGPT the obvious default choice.
The same pattern is visible in the on-device AI layer now embedded in consumer hardware, where default placement is already reshaping which tools users reach for first.
The single-app era of generative AI is giving way to a multi-platform market.
For everyday users, that means more choice, sharper competition, and very probably lower prices as each platform fights to keep the users it has.
The category ChatGPT built in three years now belongs to everyone. And that, for most people, is probably good news.
