OpenAI’s ChatGPT has exceeded 1 billion monthly active users globally, becoming the fastest application ever to reach the milestone, according to estimates released by market intelligence firm Sensor Tower.

The achievement comes as competition between OpenAI and Anthropic continues to intensify, with both companies vying for a leading position in the fast-growing artificial intelligence industry, The Caspian Post reports, citing Reuters.

According to Sensor Tower, ChatGPT reached 1 billion monthly active users in May, roughly three years after its launch. The platform achieved the milestone faster than major digital services such as Google Maps, TikTok, Instagram, and YouTube.

The firm also highlighted changing user trends, noting that US users who installed Anthropic’s Claude app during the first quarter of 2026 spent 5% less time on ChatGPT one month after installation compared with their average usage during the previous eight months.

In a separate development, Anthropic confidentially filed for a US initial public offering on Monday. Reuters has also reported that OpenAI is preparing to submit its own IPO filing in the coming weeks.

Sensor Tower data further indicated that Claude had around 56 million monthly active users worldwide as of the second quarter. However, the app’s year-over-year growth rate of about 640% far exceeded ChatGPT’s 62% growth, underscoring the accelerating competition within the AI application market.