Anthropic IPO Nears Public Filing as Valuation Slips to $1.5T

The last mega-IPO of 2026 comes into view

At the start of the year, investors expected three trillion-dollar-scale tech listings in 2026. Only one has happened so far. SpaceX went public in June. OpenAI has pushed its listing to next year. That leaves Anthropic, the maker of Claude, as the only one of the three still in play this year, and it is moving toward a stock market debut on a timeline that has slipped more than once.

According to reports citing three people familiar with the plans, Anthropic could make its IPO registration statement public as soon as Friday, October 233639. Another account gives October 26 for the public filing, with a roadshow starting November 9 and pricing the week after33. The procedural reason is the same in every version. A company that files confidentially has to publish its paperwork at least 15 calendar days before it formally starts marketing shares to investors3239. Anthropic has not officially announced any of these dates39.

The valuation story has moved more than the calendar. For most of the year, coverage described a deal raising up to $100 billion at about $2 trillion1033. After an investor day in mid-October, some current and prospective investors began talking about something closer to $1.5 trillion3436. The company is going public just as the market is getting tougher on AI valuations.

How the timeline kept shifting

The formal process began on June 1, when Anthropic said it had confidentially submitted a draft S-1 to the SEC. It said no share count or price had been set and that the offering would depend on market conditions79. A few days earlier, the company had closed a $65 billion Series H at a $965 billion post-money valuation. That came only months after a February round valued it at $380 billion810.

The timing then moved repeatedly. Reuters reported in late August that a prospectus would follow Labor Day. On September 5 it said marketing would start in mid-October at the earliest8. On September 18, the Wall Street Journal reported that the target had moved from October to November so the offering could include third-quarter results79. Bloomberg later reported that Anthropic was aiming to price before Thanksgiving, with formal marketing starting as soon as the week of November 956.

Most reports say the stock will trade on Nasdaq49, although one outlet notes that the exchange has not been formally confirmed8. Morgan Stanley, Goldman Sachs, JPMorgan and Citigroup are commonly named as lead underwriters3, and some reports add Barclays9. Reuters has also reported talks with Nvidia about a cornerstone investment of up to $10 billion10.

Prediction markets have treated the listing as likely but not certain. On Kalshi, Anthropic was the only one of 23 open contracts above 50% odds of announcing an IPO this year, at 75% as of October 192.

Why the valuation talk fell

The key moment was the October investor day in San Francisco, attended by CEO Dario Amodei and finance chief Krishna Rao34. Anthropic reportedly told attendees that third-quarter revenue reached $16.8 billion, up 45% from the previous quarter, and that it had been profitable on an adjusted basis3439. Those are huge numbers in absolute terms. The problem was the comparison: second-quarter revenue had more than doubled to $11.6 billion, so 45% growth looked like a slowdown3334.

The reported figures differ slightly. One account puts second-quarter revenue at $11.5 billion and third-quarter growth at nearly 50%, and adds a claim of positive free cash flow attributed to the Financial Times38. Either way, the direction is the same: growth is slowing, even if it remains very fast.

The costs make that slowdown matter more. Anthropic has committed at least $518 billion over roughly a decade to cloud and computing capacity3336. First-half capital spending was nearly $9 billion, compared with $2.3 billion a year earlier36. The draft prospectus reportedly shows $16.3 billion of first-half revenue and an $80.7 billion net loss38. About $72 billion of that loss is an accounting charge tied to the rising value of convertible notes, not cash spent on operations3839. Some reports focus on the size of the headline loss36, while others stress that most of it is non-cash38. The second reading is more accurate, but investors will want to see the audited reconciliation themselves.

The company's internal forecasts make the gap clearer. Anthropic reportedly projects $190 billion to $200 billion in revenue for 202834. A $2 trillion price would bake much of that forecast into today's valuation. A $1.5 trillion price would still be about 55% above the May private round, but it would leave more room for things to go wrong34.

This looks like normal IPO pricing discipline rather than a loss of confidence. Investors are not doubting that Claude has momentum. They are refusing to pay public-market prices for growth that has not yet happened.

SpaceX set the benchmark, and the warning

Nearly every account compares Anthropic with SpaceX, and that comparison helps explain why investors are cautious. SpaceX priced 555.6 million Class A shares at $135 on June 11 and began trading on Nasdaq under SPCX the next day1215. It opened at $150 and closed its first session at $160.95, up about 19%, giving it a market value of roughly $2.1 trillion1216.

The size of the deal depends on what is counted. At the offer price it raised about $75 billion1214. After underwriters bought an extra 83.3 million shares under the overallotment option, gross proceeds were about $85.7 billion1518. Either figure makes it the largest IPO on record.

Trading after the debut was rough. The stock reached an intraday high of $225.64 on June 16, then fell as low as $104.83 on August 3, below the IPO price17. It had climbed back to the mid-$140s by mid-October15, and later traded in the $150s and $160s37. Reports of the summer low differ: one puts it at $108 in late July21, and another describes a slide toward $123 to $12511. All of them describe the same pattern of a sharp first-week rise and an equally sharp drop.

Part of the volatility comes from the deal's structure. Only about 5% of SpaceX's shares were floated at first11, and the deal set aside an unusual 30% for retail buyers14. The supply of shares is still growing as lockups end. Up to 1.3 billion shares can be sold starting October 22, the largest unlock of 2026, and the standard 180-day lockup ends in early December13. Anthropic is expected to follow a similar low-float approach2934, which can push up the first-day price without showing real long-term demand.

A thinner IPO window

The wider IPO market explains why so much depends on this one deal. The second quarter of 2026 was the biggest on record for US IPOs at $104.8 billion, driven by SpaceX. The third quarter brought 30 deals raising $32.8 billion, most of it from SK hynix's US listing21. But CNBC reports that the number of US IPOs priced this year is down 33% from 2025, and several planned offerings have been postponed2. Databricks, Kraken, Plaid and Monzo have largely slipped to 202721.

OpenAI's retreat stands out most. It filed confidentially on June 826, but Sam Altman later said now would be "an ill-advised moment to go public" and pointed to 202721. Instead, OpenAI is reportedly trying to raise about $30 billion at a valuation above $1.4 trillion before Anthropic lists40. Based on those reported numbers, the two companies are now only about $100 billion apart in valuation40. The timing of OpenAI's round suggests it wants a private valuation in place before Anthropic's public filing invites side-by-side comparisons.

The broader market is also under pressure. CNBC quotes one market voice who said the reduced valuation range starting at $1.5 trillion disappointed investors and added to the pressure on AI-related stocks2. Another report notes that chip stocks have lost $2 trillion in eight trading sessions40.

What to watch

The public S-1 will be the first audited look at a frontier AI lab's finances. It should show margins, how the compute commitments are structured, and how adjusted profit is calculated3339. Then the roadshow and price range will show whether institutional investors will pay close to $2 trillion or push the deal toward $1.5 trillion. One analysis says weak demand could push the listing into December33.

Even at the lower figure, Anthropic would be the second-largest IPO by market value ever, behind only SpaceX37. For investors who buy after trading opens, SpaceX is a useful guide: most retail buyers will not get shares at the offer price37, and a strong first day says little about where the stock trades over the following months17.