Photo credit: ReutersChatGPT now holds 46.4 per cent of the global AI assistant market, the first time OpenAI's chatbot has sat under half since it created the category in late 2022. The figure comes from Sensor Tower's State of AI 2026 report, published on 16 June. Read it as a Formula 1 standings sheet and the leader still tops the table by a distance. Read the lap times, and the chasing pack has closed to within a car length. Key TakeawaysChatGPT's True Audience share unique users counted across app and web fell below 50 per cent in March 2026 and stood at 46.4 per cent by the end of May, per Sensor Tower's State of AI 2026 report.Google's Gemini holds 27.7 per cent and Anthropic's Claude 10.3 per cent; both gained ground through the year.ChatGPT keeps a commanding lead on raw users, with more than 1.1 billion monthly actives the fastest mobile app ever to reach a billion.On time spent, the top three are ChatGPT, DeepSeek and Gemini, who together take close to 90 per cent Claude sits just outside that trio.A US defence deal in February triggered a 295 per cent single-day jump in ChatGPT uninstalls, the sharpest user revolt the category has seen.What does 46.4 per cent actually measure?Sensor Tower's share figure tracks True Audience the count of unique users across both the mobile app and the web, blended into one number. That distinction matters, because a large slice of AI use happens in a browser tab rather than an app. By that measure, OpenAI crossed under the halfway line in March and kept sliding to 46.4 per cent by late May. Until January the chatbot had held a majority every month since launch. The slip looks gentle on the chart. Its meaning runs deeper: the stretch when one product simply was the market has closed. OpenAI counts its own audience on a different clock. It reports weekly active users, last pegged at 900 million in February; Sensor Tower counts monthly. The two numbers measure different things, which is why the company's billion-user headlines and the analyst's share table can both be true at once. The billion-user mark itself landed in May, faster than TikTok, YouTube or Instagram managed three years from launch. AssistantTrue Audience share (May 2026)Monthly users (Sensor Tower est. )ChatGPT46.4%1.1 billion+Gemini27.7%662 millionClaude10.3%245 millionGrok / Perplexity / DeepSeek / Meta AIunder 5% each—Source: Sensor Tower State of AI 2026 report. User counts are third-party estimates; Claude's figure sits above Anthropic's own disclosures. The standings flatter the leaderShare of users and share of attention pull in opposite directions here, and the gap is the actual story. Sensor Tower's engagement data total time spent inside the apps through the first quarter puts ChatGPT, DeepSeek and Google's Gemini together at close to 90 per cent. Claude, third on the share table, ranks fourth on the clock. China's DeepSeek, almost invisible in the share headlines, soaks up a heavy chunk of the hours on the strength of a free, low-cost offering. The lesson reads straight off an F1 timing screen. A constructor can lead the championship on points banked early in the season while a rival's car is plainly quicker over a single lap. Points pay the bills; pace decides where the season is heading. ChatGPT still banks the points. A growing share of the raw pace now belongs to a wider field.Why is Gemini the one closing fastest?Gemini's climb to 27.7 per cent and roughly 662 million monthly users owes less to the model and more to where it lives. Google folds Gemini into Search, Android, Chrome, Gmail and Workspace, so hundreds of millions meet it inside products they already open daily.Distribution does the recruiting. As the models converge on quality, the choice of which assistant a person reaches for tilts toward whichever one already sits in the tools they use each morning. That is Google's structural edge, and it compounds with every Android handset sold.February's 295 Per Cent SpikeOne event in the data shows how fast users now move. On 28 February, US uninstalls of the ChatGPT app jumped 295 per cent in a single day against a typical daily rate of about 9 per cent, Sensor Tower recorded. The trigger: OpenAI's deal to put its models on classified US military networks, struck shortly after Anthropic declined the same work on ethical grounds. One-star reviews for ChatGPT rose 775 per cent over the weekend. The beneficiary was immediate. Claude's US downloads climbed 51 per cent on the Saturday, and the app reached No. 1 on the US App Store on 2 March, outpacing ChatGPT in daily downloads for the first time. Campaigners branded the moment QuitGPT, and OpenAI's chief executive addressed the criticism publicly. Whatever its staying power, the episode proved a point the share table only hints at: brand trust and values now move install numbers as surely as features do. The money behind the usersReach and revenue diverge too. Around 13 per cent of Anthropic's users pay for a subscription, the highest conversion rate among the majors, Sensor Tower's data shows. Claude's US audience share roughly tripled over the year, from 4.4 per cent to near 14 per cent, and its global audience grew about 452 per cent year on year in May. A 10.3 per cent share that converts hard is worth more per user than a larger share that mostly browses for free. As the industry shifts from land-grab to monetisation, that ratio starts to count for as much as the headline percentage. Is this decline, or a bigger market?Falling share against a growing market reads differently from falling share against a flat one. Sensor Tower projects time spent in generative AI apps to more than double year on year in the first half of 2026, from 17.2 billion hours to about 36 billion, with spending climbing on the same curve. OpenAI's slice is thinner; the whole pie is far larger. A 46.4 per cent share of a market this much bigger can still mean more paying users than a majority commanded twelve months ago. So which assistant should you use?For a reader in India weighing the choice, the share table matters less than fit. Gemini comes built into the Android phone and Google account most people already carry, which makes it the path of least resistance for everyday questions. ChatGPT holds the deepest free-tier habit and the widest plug-in ecosystem.Claude keeps the reputation for longer reasoning and writing work, and the highest share of users who find it worth paying for. The honest read: the gap in raw capability has narrowed enough that convenience and price decide it for most people.India's chase gets steeperFor India specifically, the report carries a quieter signal. Asia logged its first download decline in early 2026 down 3.3 per cent in the first quarter, dragged by softer demand in China and India, Sensor Tower told TechCrunch.Cheaper and free models, many of them Chinese, are part of the pull. The required run rate keeps climbing for the paid Western assistants in this market: the audience is price-sensitive, the free options keep improving, and the win comes from squeezing value out of every over rather than swinging for subscription sixes the market rarely rewards.The next number that mattersThe share table will keep drifting, and the headlines will keep treating each tick as a verdict on OpenAI. The number worth watching sits elsewhere. Once the models are close enough that few users can tell them apart blindfolded, the contest moves to distribution, trust and the rate at which free users start paying. Google owns the distribution.Anthropic, for now, owns the conversion. OpenAI owns the habit of more than a billion people the stickiest asset of the three, and the one a single bad weekend showed can crack.FAQHas ChatGPT lost its lead?ChatGPT keeps the lead, and keeps it comfortably more than 1.1 billion monthly users and a 46.4 per cent share. What ended is the majority: for the first time, under half the market's users sit with a single product.Why did ChatGPT's share fall below 50 per cent?Rivals grew faster and users now switch freely between assistants. Gemini's reach through Google's products and Claude's pull among paying professionals both took share, while a February defence deal pushed some users towards alternatives.Which assistant is growing fastest?By share, Gemini is the strongest mover, reaching 27.7 per cent on the back of Google's distribution. By rate of growth, Claude is the standout, with its global audience up about 452 per cent year on year in May.How big is Claude now?Sensor Tower estimates Claude at 10.3 per cent share and roughly 245 million monthly users, with the highest paid-conversion rate of the majors at about 13 per cent. That user figure is a third-party estimate and sits above Anthropic's own disclosures.Is DeepSeek bigger than Claude?On users, Claude leads. On time spent, DeepSeek ranks higher it sits in the top three for engagement alongside ChatGPT and Gemini, a trio Claude sits just outside.Does this mean OpenAI is in trouble?The market is expanding fast enough that a smaller share can still mean more users and revenue than a year ago. The pressure is competitive rather than existential: OpenAI now defends its lead in a field with three credible names rather than one.end of article