The AI IPO Window

Anthropic filed confidential paperwork for an initial public offering with the Securities and Exchange Commission on June 1, 2026, at a valuation that had reached $965 billion the previous month ¹. OpenAI followed one week later, confirming on June 8 that it too had filed for a public listing ². Two labs that spent years describing each other as the primary competitive threat arrived at Wall Street's door within days of one another, a coincidence of timing too tight to read as anything but a shared read on when capital markets would reward frontier AI at maximum valuation.

A Week Apart, Independently

Reporting on Anthropic's move traced back to earlier signals: The New York Times had reported the company was pursuing an IPO with a target debut in the fall of 2026, well before the confidential filing became public knowledge ¹. Dario Amodei's company built toward that target from a leadership bench largely unchanged from its research-lab origins — Amodei as chief executive, Daniela Amodei as president, Mike Krieger as chief product officer, Jared Kaplan as chief science officer — a roster still weighted toward research and product rather than the finance and legal hires a public listing typically demands ¹.

OpenAI's path carried more visible preparation. Chief Financial Officer Sarah Friar, who joined after leading Nextdoor as chief executive and serving as Block's CFO before that, now manages exactly the kind of public-company transition her résumé was built for ². Sam Altman told staff he expected an IPO "within the next year," according to Wikipedia's account of internal communications, while flagging an unusual variable working against speed: continued progress toward recursive self-improvement, he suggested, might make delaying the offering the more advantageous move ². Few chief executives frame an IPO's timing around their own product's rate of improvement rather than market conditions alone.

The Restructuring That Made an IPO Possible

OpenAI's filing sat downstream of a corporate transformation finished barely eight months earlier. The company proposed converting from its capped-profit structure into a Delaware public benefit corporation in December 2024, and completed that transition on Oct. 28, 2025, after securing approval from the California and Delaware attorneys general ². Ownership split three ways under the new structure: the OpenAI Foundation retained 26%, Microsoft held 27%, and employees along with other investors split the remaining 47% ².

That restructuring solved a problem Friar's finance expertise alone left untouched: a capped-profit entity governed by a nonprofit board carries structural friction against public listing that public benefit corporation status resolves directly, giving OpenAI a conventional cap table public investors can actually evaluate. Anthropic sidestepped that particular obstacle entirely, having organized as a public benefit corporation from its 2021 founding, a difference that helps explain why its own path toward a filing generated comparatively less corporate-structure news along the way. Both companies still needed bankers fluent in valuations this large, underwriters willing to price a first-of-its-kind offering, and auditors capable of untangling compute contracts running into the hundreds of billions of dollars before either prospectus could credibly reach investors.

CoreWeave's Precedent and Klarna's Warning

Public markets already delivered one verdict on AI-infrastructure exposure. CoreWeave debuted March 28, 2025, at roughly $27 billion after trimming its raise under investor pressure, then built its contract backlog to $104 billion by the third quarter of 2026 ³. That trajectory offers OpenAI and Anthropic a genuinely encouraging comparable: a company priced cautiously at listing can still deliver spectacular growth once public, rewarding early buyers rather than punishing them for skepticism baked into the offering price.

Klarna's experience cuts the opposite direction. The fintech company completed its own IPO on Sept. 10, 2025, listing on the New York Stock Exchange under ticker KLAR at $40 a share, after a process that began confidentially in 2024, filed publicly in March 2025, then paused in April amid tariff-driven market volatility before relaunching later that year ⁶. Klarna's private valuation peaked at $46 billion in a June 2021 round led by SoftBank's Vision Fund 2, and the company's long, interrupted path back to a public listing at a far more modest footing stands as a cautionary tale about timing an offering to a market window that can close between the confidential filing and the actual debut.

The Holdouts

Cerebras illustrates how badly that window can shut. The chip designer filed an S-1 for a Nasdaq listing under ticker CBRS in September 2024, only to see the Committee on Foreign Investment in the United States open a review of an investment from G42 that October, a national-security process capable of stalling any IPO timeline indefinitely ⁴. Chief executive Andrew Feldman voiced hope in May 2025 that the company would go public within the year; instead, Cerebras raised $1.1 billion in a September 2025 Series G round valuing the company at $8.1 billion, then withdrew its IPO registration entirely that October ⁴. Feldman maintains the company still intends to go public eventually, and a January 2026 deal worth more than $10 billion with OpenAI arrived explicitly framed as groundwork laid ahead of a future listing ⁴. Regulatory review, rather than investor appetite, cost Cerebras its original window, a distinction that matters for how OpenAI and Anthropic should read the episode: private capital stayed available to Cerebras throughout, evidenced by its $8.1 billion Series G, even while the public door stayed shut on national-security grounds Anthropic and OpenAI currently avoid at comparable scale.

Databricks chose the opposite strategy outright: skip the public markets and raise instead. The data and AI platform closed a $5 billion Series M round in August 2026 led by Coatue Management, joined by Blackstone, MGX, T. Rowe Price, and Sixth Street Growth, pushing its valuation to $190 billion against a $7 billion annualized revenue run rate ⁵. Chief executive Ali Ghodsi runs a company generating public-company-scale revenue while facing zero pressure to satisfy quarterly earnings calls, a luxury OpenAI and Anthropic traded away the moment their filings became public knowledge.

By the numbers

• June 1, 2026, marked Anthropic's confidential IPO filing with the SEC ¹.
• $965 billion: Anthropic's valuation as of May 2026, the month before its filing ¹.
• June 8 brought OpenAI's confirmation that it too filed for a public listing ².
• 27%: Microsoft's ownership stake in OpenAI's public benefit corporation structure, alongside the OpenAI Foundation's 26% ².
• CoreWeave's contract backlog reached $104 billion by the third quarter of 2026, roughly a year after its own IPO ³.
• Databricks's valuation climbed to $190 billion after an August 2026 funding round, chosen over a public listing ⁵.
• Cerebras carried an $8.1 billion valuation in its September 2025 private round, one month before withdrawing its IPO registration ⁴.

What to watch

Both companies' actual debut timelines will test whether June's confidential filings translate into a 2026 listing or slip into 2027 amid the kind of market-timing pressure that stretched Klarna's own process across roughly eighteen months. Renaissance Capital and Dealogic's year-end tallies of 2026's broader IPO market will show whether OpenAI and Anthropic arrive into a receptive window or one already crowded by other large technology offerings competing for the same investor capital. Cerebras's next disclosure deserves particular attention: a fresh CFIUS resolution or a renewed S-1 filing would signal whether Feldman's stated intent to go public survives a second attempt, or whether the company follows Databricks toward permanent private-market financing instead.

Sources

1. Wikipedia contributors, "Anthropic," Wikipedia, accessed Sept. 1, 2026, https://en.wikipedia.org/wiki/Anthropic
2. Wikipedia contributors, "OpenAI," Wikipedia, accessed Sept. 1, 2026, https://en.wikipedia.org/wiki/OpenAI
3. Wikipedia contributors, "CoreWeave," Wikipedia, accessed Sept. 1, 2026, https://en.wikipedia.org/wiki/CoreWeave
4. Wikipedia contributors, "Cerebras," Wikipedia, accessed Sept. 1, 2026, https://en.wikipedia.org/wiki/Cerebras
5. Wikipedia contributors, "Databricks," Wikipedia, accessed Sept. 1, 2026, https://en.wikipedia.org/wiki/Databricks
6. Wikipedia contributors, "Klarna," Wikipedia, accessed Sept. 1, 2026, https://en.wikipedia.org/wiki/Klarna