OpenAI Falls to 23% in IPO Race as Anthropic Retains Counsel

Anthropic Is Now the Favorite to IPO Before OpenAI, and the Reasons Are Concrete

Anthropic has engaged law firm Wilson Sonsini to prepare for an IPO as early as this year. It is simultaneously negotiating a $30 billion funding round at a $900 billion valuation, a figure that now exceeds OpenAI's $852 billion round-valuation from March. And in April 2026, Anthropic overtook OpenAI in workplace AI adoption for the first time, with 34.4% of businesses on Ramp using Anthropic tools versus OpenAI's 32.3%.

These developments landed in rapid succession over the past 72 hours. Prediction markets responded immediately. OpenAI's implied probability of going public before Anthropic has dropped from 33% to 23% across Kalshi and Polymarket, a 10-percentage-point collapse in just three days. The period low hit 22%. The market resolves December 31, 2027.

Most observers assumed OpenAI, as the company that brought generative AI into the mainstream with ChatGPT, would naturally lead any public offering race. That assumption is being dismantled by procedural facts, not speculation. Anthropic is ahead on the specific milestones that precede a listing: legal counsel retained, valuation established through a fresh round, revenue trajectory accelerating, and corporate structure already compatible with public markets.

Valuation, Revenue, Legal Counsel: Anthropic Is Checking Every IPO Precursor Box Before OpenAI

The case for Anthropic going first rests on measurable progress across three dimensions. First, valuation: the proposed $900 billion round would place Anthropic above OpenAI in private-market terms. Participants in the current negotiating round include GIC, Blackstone, Sequoia, BlackRock affiliates, Goldman Sachs, JP Morgan, Fidelity, Nvidia, and Microsoft, according to El País. That investor roster reads like a pre-IPO syndicate.

Second, revenue: Anthropic's annual run rate surpassed $30 billion as of April 2026, up from roughly $9 billion at the end of 2025. That tripling in four months reflects explosive enterprise adoption of Claude. Broadcom has committed approximately 3.5 gigawatts of Google TPU capacity to Anthropic starting in 2027, supporting a $50 billion domestic AI infrastructure buildout.

Third, and most telling, Anthropic has retained Wilson Sonsini specifically for IPO preparation. Hiring a law firm is not a press release. It is a procedural commitment that triggers confidential SEC conversations, financial audits, and S-1 drafting. OpenAI has not publicly matched this step. The company has discussed a potential $100 billion funding round aimed at a $750 billion valuation, and reports suggest it is laying groundwork for a filing in the second half of 2026, but that is categorically different from retaining IPO counsel.

Why OpenAI's Corporate Complexity May Be Its Biggest Obstacle

OpenAI's structural challenges are not abstract. The company operates as a capped-profit LLC governed by a nonprofit board, a structure without precedent in public markets. Converting to a standard for-profit corporation requires nonprofit board approval, potential regulatory review, and resolution of how the original nonprofit mission will be preserved or compensated. That process introduces timeline risk that Anthropic, organized as a public benefit corporation from the start, simply does not face.

Governance history compounds the problem. The board crisis of November 2023, which nearly removed Sam Altman as CEO, left lasting questions about board independence and oversight. Any S-1 filing will require detailed disclosure of governance arrangements, executive compensation, and related-party transactions. Sam Altman's equity situation, including the terms under which he received or was denied ownership stakes, will face intense scrutiny from SEC staff and prospective institutional investors.

Meanwhile, OpenAI is diversifying in ways that could either accelerate or delay a listing. The company launched DeployCo, a consulting and services division valued at $14 billion with backing from Bain, Capgemini, and McKinsey. It has also partnered with private equity firms to push AI adoption among midsized enterprises. These moves build revenue, but they also add complexity to financial reporting and segment disclosure in a prospectus.

The strongest case for OpenAI going first is brand dominance and strategic urgency. ChatGPT remains the most recognized AI product globally. OpenAI's partnership with Microsoft provides distribution at a scale Anthropic cannot yet match. If OpenAI's board resolves the corporate restructuring quickly, the company could file an S-1 within weeks of that resolution and leapfrog Anthropic's timeline. At 23% implied probability, the market is pricing this scenario as unlikely but far from impossible. A surprise announcement of completed restructuring would reprice OpenAI's odds dramatically.

OpenAI's IPO Probability Has Been Sliding as Anthropic Accelerates

The three-day chart tells a clear story of repricing. OpenAI dropped from 33% to a low of 22% before a marginal recovery to 23%. There is notable divergence between platforms: Kalshi prices OpenAI at 16% while Polymarket holds at 30%, a 14-point spread that suggests the two venues are processing information at different speeds or attracting different trader populations. This spread is not reliable enough to draw arbitrage conclusions, but it does indicate that consensus has not yet formed on exactly how far OpenAI should fall.

The market resolves on December 31, 2027. That gives OpenAI roughly 19 months to complete its corporate restructuring, file with the SEC, conduct a roadshow, and price shares. Anthropic's retention of Wilson Sonsini and its accelerating revenue make a 2026 listing plausible. If Anthropic files its S-1 before year-end, OpenAI's probability will likely compress further toward the mid-teens.

For OpenAI bulls, the math works only if Anthropic's IPO timeline slips. One potential obstacle: Anthropic's alarm over unauthorized secondary share sales suggests the company's cap table may have complications that require cleanup before going public. If those issues delay Anthropic's filing, the window reopens for OpenAI. But as of today, the procedural evidence favors Anthropic, and prediction markets are adjusting accordingly.