OpenAI confidentially filed its S-1 IPO prospectus with the SEC on 22 May 2026, setting the stage for what could be the largest technology IPO in US history. Here is what UK investors need to know about the OpenAI IPO, the expected date, valuation, risks, and what happens next.
OpenAI confidentially filed its S-1 IPO prospectus with the SEC on 22 May 2026, setting the stage for what could be the largest technology IPO in US history. Here is what UK investors need to know about the OpenAI IPO, the expected date, valuation, risks, and what happens next.
Quick facts
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When is the OpenAI IPO?
OpenAI is laying the groundwork for a public listing in Q4 2026, and the company reportedly wants to go public before rival Anthropic, which is also preparing a late-2026 listing. Sam Altman is reportedly pushing for a September listing, with Goldman Sachs, Morgan Stanley, and JPMorgan leading the deal.
OpenAI itself has cautioned that a listing "may be a while," and the company's cash burn — projected at roughly $27 billion for 2026 sits at the centre of a fierce debate over whether the artificial intelligence boom is a generational platform shift or a late-cycle bubble. Investors should treat all dates as indicative until an official announcement is made.
The confidential filing means the prospectus details stay private until approximately 15 days before the public roadshow, that public S-1 amendment will be the first opportunity for investors to scrutinise audited financials, risk factors, and the full terms of the Microsoft commercial agreement.
What is OpenAI worth?
OpenAI raised $122 billion at an $852 billion post-money valuation in March 2026, with SoftBank and Microsoft leading the round. The company is targeting a debut valuation above $1 trillion, though this remains subject to public market demand at the time of listing. FutureSearch
At the figures reportedly discussed, the OpenAI IPO would price well ahead of any listed software peer on revenue multiples, leaving little room for execution missteps. Danelfin
Private valuations reflect terms negotiated between specific buyers and sellers. They are not a guaranteed IPO price.
The bull case for OpenAI
OpenAI is generating roughly $2 billion per month in revenue, hit an annualised $25 billion run rate by March 2026, and counts 50 million consumer subscribers plus 9 million business users. Enterprise contracts now drive more than 40% of revenue. Robo Rhythms
The company grew revenue faster than Alphabet and Meta did at comparable stages of development. ChatGPT remains the most widely adopted AI consumer product on record, and its models are deeply embedded in Microsoft's entire product suite from Copilot to Azure providing structural distribution that rivals cannot easily replicate.
The bear case for OpenAI
OpenAI remains heavily loss-making. The company does not expect to reach profitability until around 2030, and internal projections suggest losses of $14 billion in 2026 alone. HSBC analysts estimate OpenAI may need over $207 billion in additional funding by 2030 to maintain operations. CMC Markets
Google's Gemini has grown its web traffic share from 5.7% to 21.5% in the past 12 months, while ChatGPT's share has dropped from 86.7% to 64.5% over the same period. Anthropic, xAI, and Meta are all investing heavily in the same space. CMC Markets
Structurally, the OpenAI Foundation will retain a 26% stake with controls that may limit shareholder influence, and Microsoft holds roughly 27% meaning public investors will own a minority of a company where major strategic decisions are shaped by two large block holders.
What happens next
The key milestone to watch is the public S-1 amendment, filed approximately 15 days before the roadshow. This will include audited financials, the full risk factor section, ownership structure, and terms of the Microsoft partnership.
IPO shares are typically allocated to institutions during the roadshow. Retail investors usually access them at or after day one. A 180-day lock-up typically restricts insiders from selling after listing when large tranches expire, selling pressure can weigh on the price.
Investing in shares involves risk. The value of investments can go down as well as up and investors may receive back less than their original investment. Past performance is not a reliable indicator of future results.
Investors interested in the AI sector can follow developments surrounding OpenAI while exploring other publicly traded technology and artificial intelligence companies available through XTB shares.
The details below are based on publicly reported information and market speculation as of June 2026. IPO timing, valuation and listing details may change before any official announcement.
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