Both companies are now formally in the IPO queue. Anthropic confidentially filed its S-1 with the SEC on June 1. OpenAI followed exactly one week later, on June 8, announcing the filing itself rather than letting it leak. Goldman Sachs and Morgan Stanley are bookrunning both deals, each expected to raise at least $60 billion. And this week, SpaceX prices the largest IPO in history at roughly $1.75 trillion (pricing June 11, first trade June 12), more than four times oversubscribed.
When I first published this page on March 31, the question was whether these IPOs were coming at all. The questions that matter now are when, and at what price. This page is the standing forecast on both questions; the full company models behind it are in our Anthropic forecast (revenue, compute, Mythos timing) and OpenAI forecast (revenue, losses, and the step-change bet).
tldr Anthropic lists first: median date December 15, 2026, at a median first-day market cap of $1.10 trillion. OpenAI follows around late March 2027, at a first-day cap that is, surprisingly, almost exactly the same: $1.08 trillion at the median. The gap that defined my March forecast is gone, and not because OpenAI fell. The June 12 suspension of Claude Fable leaves both medians where they were; it widens Anthropic's tails, pushing its worst-case listing date out to April 2028 and lowering its downside valuation.
The forecasts on this page were re-run at high effort on June 10, 2026; a June 18 update widened Anthropic's IPO-date tail to reflect the Fable suspension.
Anthropic's June 1 filing started a procedural clock. Confidential SEC review for a company of this scale typically runs three to six months; SpaceX is about to complete the trip from confidential filing to first trade in roughly 72 days. That fast track is what the left side of Anthropic's distribution looks like: a late-September debut (p10 September 24) is mechanically feasible, and press reports say the company is considering listing as soon as October.
Prediction markets believe the fast track. Polymarket puts 69% on an Anthropic listing by October 31 and 90% by year-end. My median of December 15 is deliberately slower, because Anthropic carries friction SpaceX doesn't. Gross-versus-net revenue accounting (Anthropic books cloud-reseller end-customer spend as its own revenue) is the question SEC reviewers will spend the most time on. AI-safety risk factors are novel disclosure territory with no settled template. And the Pentagon supply-chain-risk designation is still live: the D.C. Circuit has the case under advisement, and Secretary Hegseth has reportedly refused to reconsider the designation. Then on June 12, the friction turned concrete: a Commerce Department export-control order pulled Claude Fable and Mythos 5 offline worldwide, three days after they launched, which shows the government can switch off the flagship on short notice and puts that risk directly into the S-1, pushing Anthropic's worst-case listing date out to April 2028. None of that blocks a listing. All of it adds comment cycles.
OpenAI filed on June 8 and then immediately played it cool: "We have not decided on timing yet; it may be a while… this gives us the option to go public sooner if that ends up being best." That sentence is most of the forecast. Sam Altman has reportedly pushed for a debut as early as September; CFO Sarah Friar has consistently preferred 2027, citing public-company readiness. My median is March 25, 2027, with a long right tail (p90 May 2028). Polymarket gives 48% to an OpenAI listing by December 31; my distribution implies about a third. I think the market is underweighting how literally OpenAI means "it may be a while."
The thesis I led with in March, that the ability to raise ungodly amounts of private capital removes the single greatest motivation to list, half-survived. Both companies filed anyway, because the queue position itself is valuable. But a confidential filing is an option, not a commitment, and OpenAI is treating it as exactly that. Anthropic is the one behaving like a company that intends to exercise. It picked lead underwriters within 48 hours of filing, and it has a competitive prize to capture: first pure-play frontier AI stock. Polymarket gives Anthropic 83% odds of beating OpenAI to the bell. My forecast says 63%: still clearly the favorite, but the market is underpricing how fast OpenAI could move if Altman wins the internal timing argument and decides the queue position is worth exercising.
Now the valuations.
For Anthropic, I forecast a median first-day close of $1.10 trillion, a 14% premium to the $965 billion Series H that closed on May 28. The premium is not speculative: secondary-market buyers were bidding around $1.05 trillion with asks at $1.15 trillion before the S-1 even went in. Revenue run rate crossed $47 billion in May and is compounding at roughly $96 million of new annualized revenue per day, and the company has projected its first operating profit for Q2 2026: $559 million on $10.9 billion of quarterly revenue.
The downside scenarios (p10 $750 billion) are concentrated in one place: the S-1 review itself. If the SEC forces gross-to-net revenue restatement, headline ARR drops 20-40% in one print and the multiple math everyone is carrying breaks. Operating margins around 5% give public investors a second reason to price conservatively. The Fable suspension adds to the list: an unresolved export order against the flagship is the kind of overhang public investors discount over the first quarters of trading, and our full Anthropic forecast puts the 90-day downside near $627 billion. And three mega-IPOs (SpaceX's $75 billion raise this week, then at least $60 billion each for Anthropic and OpenAI) are hitting the same pool of institutional capital within a few quarters of each other.
The upside (p90 $1.7 trillion) is the retail scenario. SpaceX allocated up to 30% of its offering to retail, triple the usual, and demand still ran past 4x. Cerebras popped 68% on day one in May. There is exactly one pure-play frontier-AI equity coming to market first, and scarcity at trillion-dollar scale has no precedent to price against.
For OpenAI, the median is $1.08 trillion against a March private mark of $852 billion. The medians being nearly identical is the result I did not expect: in March I forecast OpenAI's first-day cap at nearly double Anthropic's. The gap closed because Anthropic doubled, not because OpenAI moved. Part of OpenAI's premium is also mechanical rather than triumphant: the later it lists, the more revenue compounds under the number. And part of the distribution covers scenarios where it doesn't list by end-2027 at all.
I'd also distinguish day one from day ninety, for OpenAI especially. Our full OpenAI forecast puts the expected 90-day post-IPO market cap at $0.86 trillion, below the first-day median here, and that is not a contradiction. Day-one demand is a narrative market; ninety days is enough time for institutional models to digest the loss line, which FutureSearch estimates at $25-26 billion GAAP for 2026 against the widely cited $14 billion non-GAAP figure. Cerebras gave back 10% the day after its pop. Facebook and Uber both traded below their IPO marks for a year or more. A strong OpenAI open and a fading first quarter is my modal path.
So the race, as I now see it: Anthropic prices first, around year-end, at a small premium to its last private round, and OpenAI follows a quarter later at roughly the same market cap on perhaps 40% of the revenue. On day one, public markets will price the AI race directly for the first time, and the surprise in these forecasts is that they price it close to a tie. What won't be a tie is what happens in the following ninety days.
About this forecast. This page was first published on March 31, 2026 (forecasting a March 2027 Anthropic IPO at a $560 billion first-day market cap, with OpenAI following in May 2027 at $1.04 trillion) and updated on April 8 after Anthropic's $30 billion run-rate announcement moved the Anthropic median to $643 billion. This June 10 refresh re-ran every forecast at high effort after the $65 billion Series H, the $47 billion run-rate disclosure, and both confidential S-1 filings. The largest revisions: Anthropic's median first-day cap roughly doubled and its median listing date pulled in by a quarter; OpenAI's valuation held nearly flat while its date pulled in by about two months. A June 18, 2026 update then folded in the launch and June 12 export suspension of Claude Fable, which widened Anthropic's IPO-date tail and downside without moving its medians. The full financial models behind each company are in our Anthropic forecast and OpenAI forecast.
Run this forecast yourself by connecting FutureSearch to Claude. Then ask Claude to refresh the numbers any time the news cycle moves.