Inside OpenAI's Confidential S-1 Filing: The Numbers Behind the Trillion-Dollar AI IPO

The Filing and Underwriters

The process began in secret. On May 20, major outlets reported that OpenAI planned to confidentially file its S-1 with the SEC as soon as May 22, a timeline the company met . The lead underwriters on the deal are Goldman Sachs and Morgan Stanley, with JPMorgan also participating in a joint role . The target window for going public is September to November 2026, with September cited as the earliest possible date and Q4 seen as more likely .

Valuation: From Private Giant to Public Record-Breaker

OpenAI's last private funding round in March 2026 raised approximately $122 billion at an $852 billion post-money valuation, making it the largest private fundraise on record . For its IPO, underwriters are now targeting a market capitalization between $850 billion and $1 trillion . To put this in context, a debut at that level would eclipse Saudi Aramco's $1.7 trillion valuation at its 2019 IPO, though Aramco's actual capital raised was only $25.6 billion .

The path to this valuation was paved by a significant corporate restructuring. In October 2025, OpenAI completed its conversion from a capped-profit entity into a public benefit corporation called OpenAI Group PBC, controlled by a nonprofit named the OpenAI Foundation . Under this structure, ownership breaks down to approximately 26% for the OpenAI Foundation, 27% for Microsoft (with a stake valued at around $135 billion), and 47% combined for employees and other investors . Notably, CEO Sam Altman holds 0% equity in this new structure .

Financials: Soaring Revenue, Staggering Losses

The financial picture is a study in contrasts. On one hand, revenue growth is spectacular. Sacra estimates OpenAI hit $25 billion in annualized revenue as of February 2026, a dramatic rise from $20 billion at the end of 2025 and just $6 billion at the close of 2024 . On the other hand, the cost of running frontier AI models is immense.

OpenAI's gross margin is estimated at just 33%, heavily constrained by inference compute costs that reached $8.4 billion in 2025 and are projected to rise to $14.1 billion in 2026 . The company is projected to book a net loss of approximately $14 billion for the 2026 fiscal year . In brutally simple terms, OpenAI reportedly loses $1.22 for every dollar of revenue it earns . The company has signed roughly $600 billion in cumulative compute commitments that extend through 2030, a liability flagged by CFO Sarah Friar as a material risk .

A critical financial maneuver improved the long-term outlook. In April–May 2026, OpenAI renegotiated its revenue-sharing agreement with Microsoft. The original uncapped deal would have obligated OpenAI to share 20% of its revenue—potentially totaling $135 billion by 2030. The revised agreement caps total payments to Microsoft at $38 billion through 2030, saving OpenAI an estimated $97 billion if it hits its growth targets . The deal also liberated OpenAI to pursue non-exclusive cloud partnerships with Amazon and Google .

Competitive Pressures and Legal Landscape

The IPO arrives amid a shifting competitive landscape. ChatGPT's app market share has fallen from roughly 69% to 45% as competitors like Google Gemini and xAI's Grok gain traction, though the service still boasts around 900 million weekly active users .

A significant legal overhang was removed just two days before the S-1 filing when a federal judge dismissed Elon Musk's lawsuit against OpenAI on statute-of-limitations grounds, a decision reported around May 20 . However, the company still faces a multistate probe by a coalition of state attorneys general investigating potential user harm from its products, although no formal charges have been filed .

A $3.6 Trillion AI IPO Pipeline

OpenAI’s filing is not happening in isolation. It is the centerpiece of a historic wave of AI public listings. Anthropic confidentially filed its own S-1 on June 1, 2026, at a reported valuation of approximately $965 billion . SpaceX simultaneously launched a roadshow for a roughly $1.75 trillion debut. Collectively, these three filings represent a prospective IPO pipeline of around $3.6 trillion, a concentration of value that is set to redefine public market exposure to frontier AI .