For the First Time, ChatGPT Reportedly Has Less Than Half of the AI Assistant Market

OpenAI reportedly no longer dominates the AI assistant market. A report from Sensor Tower (reported on by TechCrunch) says that although OpenAI’s ChatGPT is still the number one-ranked AI assistant product, it can now brag only the plurality, not the majority of users.

ChatGPT’s grip on AI assistant market share was much stronger at the start of this year, when it reportedly had more than 50%, but as of May 31, it was down to an all-time low of 46.4%, TechCrunch notes.

Around 2023, ChatGPT looked on track to become a “genericized trademark”—a term for when a trademarked name becomes the accepted term for a whole product category. But anecdotally, I don’t hear people say things like “just ChatGPT it” anymore.

In March, OpenAI made a deal with the Pentagon at a time when its chief competitor, Anthropic, was noisily feuding with the Pentagon over that company’s stance against autonomous killer robots and AI mass surveillance. Anthropic managed to become a sort of folk hero, even if that reputation was probably somewhat unearned.

Some AI users revolted in the wake of OpenAI’s deal, which CEO Sam Altman acknowledged looked “opportunistic and sloppy.” An anti-OpenAI organization called QuitGPT, which calls itself a “grassroots campaign by the people, for the people,” formed. Its website claims that “ChatGPT took Trump’s killer robot deal. It’s time to Quit.” That site says 4 million people have joined its boycott.

And at the same time, OpenAI more broadly was in the midst of a wrenching and sudden shift in its self-image, from freewheeling and fun to…whatever it is now. Anthropic’s surge in revenue-generating enterprise customers had triggered a “code red” in late 2025. By mid-March of 2026, OpenAI was reportedly changing its internal strategy to focus on enterprise and productivity. About a week after that report, OpenAI killed its video-generating app, Sora.

Oh, and ChatGPT also started showing ads earlier this year. When an Anthropic Super Bowl commercial made fun of OpenAI for its ads, Sam Altman responded by getting embarrassingly testy in public.

In short, ChatGPT’s loss of dominance arrived during a less-than-ideal year for its brand image—although in the “plus” column, OpenAI won its legal war with Elon Musk, so its year hasn’t been completely without high points.

The market share of Anthropic’s Claude, according to this report, is 10.3%—nowhere near Gemini’s 27.7%, let alone ChatGPT’s 46.4%. However, earlier analysis of the Sensor Tower report from Reuters says that Claude’s pace of year over year monthly active user growth absolutely blew OpenAI’s away, with 640% for Claude, and only 62% for ChatGPT.

If you’re wondering how Grok, the AI assistant whose parent company is SpaceX, measures up in the Sensor Tower report, the answer is not very well. It’s essentially lumped into the “other” section, alongside Perplexity, MetaAI, and DeepSeek, which collectively boast 5% of AI assistant market share.