OpenAI confidentially filed a draft Form S-1 with the U.S. Securities and Exchange Commission on or around May 22, 2026, kicking off a process that bankers and reporters expect to land in public markets in the fourth quarter at a valuation between $852 billion and roughly $1 trillion, according to Fortune and Axios. Goldman Sachs and Morgan Stanley are reported to be the lead underwriters.
The move arrives a month after SpaceX flipped from confidential to public S-1 and listed plans to trade under the symbol SPCX, as we covered here. If the calendar holds, OpenAI and SpaceX will be the two largest U.S. IPOs ever attempted, both inside a single fall window — a setup with no real precedent in modern capital-markets history.
What we know about the filing
A confidential S-1, allowed under the JOBS Act and extended by the SEC in 2017 to all issuers, is a draft registration statement reviewed by SEC staff without immediate public disclosure. The full prospectus must be filed publicly on EDGAR at least 15 days before the issuer commences its roadshow under the SEC’s draft-registration procedures. Working back from a target Q4 2026 listing, the public S-1 would likely land in August or September.
OpenAI declined to confirm specific timing, telling Axios only that “as part of normal governance, we regularly evaluate a range of strategic options.” That phrasing is consistent with how late-stage pre-IPO issuers typically acknowledge a confidential filing without confirming it.
| Item | Reported detail |
|---|---|
| Filing type | Confidential draft S-1 (DRS) |
| Filing date (reported) | On or around May 22, 2026 |
| Lead underwriters | Goldman Sachs, Morgan Stanley |
| Listing target | Q4 2026 (Labor Day–Thanksgiving window) |
| Current private valuation | ~$852B (March 2026 funding) |
| IPO valuation range (reported) | $852B – ~$1.0T |
| Issuer | OpenAI Group PBC |
The cap table the S-1 will finally reveal
OpenAI’s October 2025 restructuring is the foundation everything else sits on. The for-profit subsidiary was converted into a Delaware public benefit corporation called OpenAI Group PBC, while the original nonprofit was renamed the OpenAI Foundation. That foundation still controls the PBC’s board.
Per disclosures from Microsoft’s official blog, Fortune, and CNBC, the post-restructuring economic ownership is:
| Holder | Stake | Implied value at $1T |
|---|---|---|
| Microsoft | 27% | ~$270B |
| OpenAI Foundation (nonprofit) | 26% | ~$260B |
| Employees and other investors | 47% | ~$470B |
Microsoft’s stake was diluted from roughly 32.5% on an as-converted basis prior to the March 2026 mega-round that closed at an $852 billion post-money valuation. As part of the recapitalization, Microsoft retained access to OpenAI technology through 2032, including any system later certified as AGI by an independent panel.
The financial picture investors will be staring at
OpenAI’s revenue trajectory has accelerated faster than any software company in history. CFO Sarah Friar has confirmed roughly $13 billion of 2025 revenue (up from $6 billion in 2024 and $2 billion in 2023), and ARR has reportedly crossed $25 billion in early 2026 based on March press accounts. The S-1 will give investors the first audited view of those numbers.
Less glamorous: the company remains deeply unprofitable. Multiple outlets have reported Q1 2026 losses of roughly $1.22 per $1 of revenue, with cash consumed by training and capacity buildouts at hyperscaler-owned data centers. The S-1 will need to provide three things investors do not yet have:
- GAAP financials. A full income statement, balance sheet, and cash-flow statement audited by an independent accounting firm — not investor-deck slide bullets.
- Compute commitments. The dollar value and timing of multi-year compute purchase obligations with Microsoft, Oracle, and the consortium behind OpenAI’s planned Stargate facilities.
- Customer concentration and unit economics. Especially the contribution of ChatGPT subscriptions versus API revenue, and gross margin progression on inference workloads.
Why the structure matters for public-market investors
OpenAI Group is a Delaware public benefit corporation, which means directors must consider a stated public-benefit purpose (broadly described in OpenAI’s filings as ensuring “AGI benefits all of humanity”) alongside shareholder interests. The PBC structure does not exempt the company from securities laws, but it does change the fiduciary calculus directors must perform — a fact that will be disclosed and litigated in the registration process.
Control sits with the nonprofit foundation, which retains board authority over the PBC. Public shareholders will own equity exposed to OpenAI’s economics but will not hold the levers of governance the way they would in a conventional C-corp IPO. Investors should expect detailed risk-factor language on this point.
The bottom line for capital markets
If OpenAI does ultimately list in Q4 2026 at anywhere near a trillion-dollar valuation, it will be the largest U.S. IPO ever — roughly 30 times the size of Visa’s $17.9 billion 2008 debut, which currently holds the record. Combined with SpaceX, the two listings could absorb more new-issue equity in a single quarter than any IPO window since 1999. How public markets price unaudited growth, governance carve-outs, and tens of billions in compute commitments will shape the entire AI capital structure for years.
Sources
- Fortune — The big questions OpenAI’s trillion-dollar IPO filing may finally answer (May 22, 2026)
- Axios — OpenAI prepares confidential IPO filing (May 20, 2026)
- Fortune — OpenAI completes for-profit restructuring, grants Microsoft a 27% stake (Oct 28, 2025)
- CNBC — OpenAI completes restructure, solidifying Microsoft as a major shareholder (Oct 28, 2025)
- Microsoft — The next chapter of the Microsoft–OpenAI partnership (Oct 28, 2025)
- OpenAI — Our structure
- SEC Division of Corporation Finance — Draft Registration Statement Processing Procedures
- SaaStr — OpenAI revenue trajectory and CFO commentary
- Sacra — OpenAI revenue tracker
Disclosure: This article was produced with AI assistance and reviewed before publication. It is for informational purposes only and is not investment advice.