ChatGPT hits 1 billion users — but Claude is closing the gap fast
ChatGPT crossed 1 billion monthly active users in May 2026 — roughly two and a half years after launch, making it the fastest product in history to hit that scale, ahead of TikTok, Instagram, and YouTube. OpenAI is now preparing an IPO that could target a valuation above $1 trillion. The problem: the company projects $14 billion in losses for 2026, and a rival is quietly eating into its lead.
The numbers behind the milestone
According to data from Sensor Tower, ChatGPT's 62% year-on-year growth sounds impressive until you compare it to Claude. Anthropic's chatbot has 56 million monthly active users — a fraction of ChatGPT's base — but grew 640% over the same period. That gap is narrowing faster than headline numbers suggest.
The substitution effect is already measurable. US users who installed Claude in Q1 2026 spent 5% less time on ChatGPT just one month later, per Sensor Tower estimates. Five percent sounds small, but it signals that brand loyalty to OpenAI is no longer automatic. Users are shopping around.
The IPO race
Both companies are heading to public markets. Anthropic filed confidentially for a US IPO on June 2, 2026. OpenAI filed its own confidential S-1 on May 22, with Goldman Sachs and Morgan Stanley listed as leads, targeting a Q4 2026 debut, per Investing.com.
OpenAI reported roughly $13.1 billion in revenue for 2025 and expects annualized revenue around $25 billion — but the $14 billion loss projection for 2026 raises a real question about whether the unit economics work at any scale. Profitability isn't expected until around 2030, according to CMC Markets.
Anthropic carries its own structural advantage in the enterprise market: its Claude models currently account for around 40% of enterprise LLM spending, compared to OpenAI's 27%. Businesses in regulated industries have shown a preference for Anthropic's safety-focused positioning — a detail both IPO prospectuses will need to address directly.
What comes next
The billion-user milestone is real, but it's also a ceiling of sorts. Sustaining that base — converting free users to paying subscribers, retaining them against a faster-growing competitor — is where OpenAI's $1 trillion valuation story lives or dies. For consumers, the practical outcome is straightforward: competition between ChatGPT and Claude is intensifying, which tends to mean better products and more pricing pressure in the near term. Neither company is going away, but the AI market is no longer a one-horse race.