OpenAI's ChatGPT, the trailblazing artificial intelligence chatbot, has seen its global market share fall below 50% for the first time since its launch over three and a half years ago. While still the most widely used AI assistant, its dominance is being challenged by a growing field of competitors, most notably Google's Gemini and Anthropic's Claude.
According to analytics firm Sensor Tower's 'State of AI Report for 2026', ChatGPT's market share stood at 46.4% by the end of May, a notable decrease from its position above 50% earlier in the year. Google's Gemini has captured 27.7% of the market, benefiting significantly from its integration into Google's extensive ecosystem. Anthropic's Claude has also made substantial inroads, achieving 10.3% market share and gaining recognition for its strong performance in productivity applications.
The report highlights a shifting landscape where users are increasingly willing to migrate between different AI assistants. This behaviour is influenced not just by features, but also by factors such as brand trust and values alignment. For instance, a measurable spike in uninstalls for ChatGPT was observed following OpenAI's deal with the U.S. Department of Defense in February, suggesting user sentiment plays a role in retention.
The overall AI app market is experiencing rapid growth, with Sensor Tower estimating nearly 2.3 billion app downloads globally and over £3.3 billion (equivalent to $4.2 billion) in consumer spending projected for the first half of 2026. This marks a significant increase from £1.45 billion in spending during the first half of 2025, indicating a strategic shift within the industry towards monetisation beyond pure user acquisition. However, the report also notes a deceleration in both download and spend growth rates, suggesting a maturing market.
For businesses in the UK, this competitive environment presents both opportunities and challenges. The proliferation of AI tools offers greater choice and specialisation, allowing companies to select assistants best suited to their specific needs, from enhancing customer service to streamlining internal operations. For consumers, the increased competition could lead to more innovative features, better pricing models, and improved user experiences as platforms strive to differentiate themselves. The UK's Information Commissioner's Office (ICO) continues to monitor the development and deployment of AI, working alongside the government to ensure data protection and ethical considerations are upheld, while the EU AI Act, though not directly applicable, sets a global precedent that UK regulations will observe.