OpenAI files for US IPO, entering race with Anthropic and SpaceX

OpenAI, the maker of ChatGPT, has confidentially filed for an IPO in the US, following rival Anthropic in the race to go public as investors seek opportunities from the artificial intelligence (AI) boom.

The company did not disclose the size or terms of the offering, and said the timeline remains undetermined. “It may take a while because there are things we want to do more easily as a private company,” OpenAI said in a statement on Monday. Reuters earlier reported that the “AI giant” is targeting a valuation of up to $1 trillion in its stock market debut, which could take place as early as September.

At that valuation, OpenAI would pave the way for three trillion-dollar companies to list in quick succession, seen as the most important test of investor appetite for high-growth tech stocks in the past decade. Elon Musk’s SpaceX is the pioneer, having filed for an IPO that could become the largest in history if completed, with a $75 billion offering at a $1.75 trillion valuation.

The AI era

IPOs from Anthropic and OpenAI would crystallize a transformative phase in the technology industry and global markets, as AI rapidly emerges as the defining investment theme of the decade. OpenAI earlier this year said it was raising $110 billion at an $840 billion valuation from heavyweight investors including SoftBank, Amazon, and Nvidia. The company also disclosed that ChatGPT has more than 900 million weekly active users and over 50 million paid subscribers.

The IPO comes after OpenAI renegotiated its partnership with Microsoft, one of its earliest investors, allowing the AI pioneer to forge new ties with Amazon and Alphabet (Google). Microsoft’s initial $13 billion investment in 2019 paved the way for OpenAI’s rise and boosted growth in its Azure cloud computing business. In March, OpenAI said it was generating $2 billion in monthly revenue, growing four times faster than companies that once dominated the internet and mobile eras, such as Alphabet and Meta, compared with about $1 billion in revenue in the final quarter of 2024.

Altman vs Musk

OpenAI was founded in 2015 as a nonprofit research organization, but created a for-profit arm four years later to cover soaring AI development costs. The unusual structure, where the nonprofit controls the for-profit entity, came under intense scrutiny in late 2023 when CEO Sam Altman was briefly fired before returning days later amid staff backlash. In December 2024, OpenAI announced plans to restructure by creating a public benefit corporation, arguing the move would help raise larger amounts of capital and ease restrictions imposed by the nonprofit.

The plan quickly drew controversy, facing criticism from Elon Musk, an early investor. Musk later sued OpenAI, accusing Altman and other leaders of turning the nonprofit into a vehicle for private enrichment. In May, a US jury ruled against Musk, concluding that the AI company was not accountable to the world’s richest man over claims it had strayed from its original mission to serve humanity. The unanimous verdict removed a major hurdle to the IPO, analysts said, eliminating the legal baggage that public-market investors often fear.