OpenAI disclosed Monday that it had submitted a confidential draft registration statement to the Securities and Exchange Commission, the formal beginning of an IPO process that, at the company’s most recent post-money valuation of $852 billion, would rank it among the 15 largest constituents of the S&P 500 on day one. The filing arrives eight days after Anthropic submitted its own confidential S-1 on June 1, and into a market that CNBC has already begun describing, alongside a SpaceX roadshow pitching the rocket company as an A.I.-focused space business, as a potential trio of the largest public-market debuts on record.

The announcement was notable mostly for its tone. “We expect it to leak so we’re just announcing it,” the company said in the statement posted to its website, before adding that “there are things we want to do that are likely easier as a private company.” That’s an unusual register for a Rule 135 disclosure, and it tracks with what Sarah Friar, OpenAI’s chief financial officer, told the Associated Press in April: that the company had been “acting with the good hygiene of a public company” for some time. A person familiar with the plans told CNBC that OpenAI intends to facilitate a tender offer letting employees sell into the $852 billion mark.

The filing also lands a week after an advisory jury decided Elon Musk’s 2024 suit against the company, finding he had waited too long to press his claims. Musk, on X, called the verdict “a calendar technicality.”

The harder number for prospective underwriters sits in Ramp’s May 2026 AI Index. Drawn from spending data across more than 50,000 companies representing over $100 billion in annual business spend, the index showed Anthropic passing OpenAI in U.S. business adoption for the first time: 34.4 percent of sampled companies paying for Anthropic products against 32.3 percent paying for OpenAI’s. In April, Anthropic’s share rose 3.8 points; OpenAI’s fell 2.9.

“What Anthropic did worked really well,” Ara Kharazian, the Ramp economist, told TechCrunch, describing a strategy of courting technical customers first and broadening outward. Ramp itself flagged caveats: Anthropic’s per-token pricing creates an incentive misaligned with cost-conscious buyers, the lead was partly offset by a new compute deal with SpaceX, and Claude has lately drawn “frequent outages, rate limits, and increasing dissatisfaction.” Uber, in the same release, disclosed it had already exhausted its 2026 A.I. budget.

The S-1 timing isn’t accidental. Going public on a falling enterprise share is harder than going public on a rising one, and the calendar is closing.

Sources