OpenAI expects to reach 700 million weekly active users for ChatGPT this week, up from 500 million in March, representing a more than fourfold year-over-year increase, the company announced Monday.

The figure applies to all ChatGPT artificial intelligence products — free, Plus Pro, Enterprise, Team, and Edu — and comes as daily user messages exceed three billion, according to the company. The growth rate is also picking up, compared to 2.5 times year-on-year growth at this time last year.

"Every day, people and teams are learning, creating, and solving harder problems," said Nick Turley, VP of Product at ChatGPT, in announcing the benchmark.

OpenAI now has five million paying business users on ChatGPT, up from three million in June, as businesses and educators increasingly incorporate AI tools.

ChatGPT still has a long way to go before reaching the reported user numbers for Google's AI search product, AI Overviews.

Alphabet CEO Sundar Pichai stated during the company's quarterly earnings call that the product, which summarizes search results, now has approximately two billion monthly users in more than 200 countries.

According to Pichai, the company's AI chatbot, the Gemini App, has over 450 million monthly active users.

The OpenAI milestone comes after the company announced last week that it had raised $8.3 billion from a group of top investors, including Dragoneer Investment Group, Andreessen Horowitz, Sequoia Capital, Coatue Management, and Altimeter Capital.

According to a person familiar with the deal, the investment is part of a $40 billion fundraising round led by SoftBank. The person requested anonymity in order to discuss financial information. The fundraiser was completed ahead of schedule and was five times oversubscribed.

OpenAI's annual recurring revenue is now $13 billion, up from $10 billion in June, and the company expects to exceed $20 billion by the end of the year.

Even at a $300 billion valuation and a $20 billion revenue run rate, OpenAI will require significant capital to support its global expansion.

The company's Stargate joint venture with SoftBank, Oracle, and MGX plans to invest up to $500 billion in AI infrastructure over four years.

OpenAI has already signed a $30 billion-per-year lease with Oracle for 4.5 gigawatts of data centre capacity in the United States, a five-year, $11.9 billion agreement with CoreWeave, and an expansion into Europe with Stargate Norway.

OpenAI is also collaborating with the Emirati firm G42 to build a massive data centre in Abu Dhabi.

The company's competitors are taking similar actions.

According to a leaked memo shared with Wired, Anthropic CEO Dario Amodei is reversing course on Middle Eastern funding, writing that it has become "substantially harder to stay on the frontier" of AI development without access to Gulf sovereign wealth. It represented a shift from Anthropic's previous stance.

Last year, CNBC reported that Anthropic refused to accept funds from Saudi Arabia as it sought new investors.

The new capital and usage growth highlight a growing investor appetite for AI platforms as competition heats up. Anthropic is also in talks to raise up to $5 billion at a $170 billion valuation, building on a $3.5 billion round earlier this year that valued the company at $61.5 billion.