Anthropic's S-1 slips to November as EDGAR stays empty on day of expected filing

Anthropic’s public S-1 didn’t land on EDGAR by September 26, closing out the late-September window that bankers at Morgan Stanley and Goldman Sachs had been steering toward and pushing the largest technology listing since SpaceX into November at the earliest. The company filed its confidential draft under Rule 135 on June 1; SEC rules require the public prospectus to sit with investors for at least 15 days before a roadshow can start, and that clock hasn’t begun.

Prediction markets caught the shift before the calendar did. In the 24 hours after Dario Amodei published his September 12 essay “We Must Pace the Frontier,” Kalshi’s contract on Anthropic confirming an IPO before November fell from 70% to 50%, its December contract from 84% to 71%, and its January contract from 92% to 81%. The “before December 1” contract now sits at 50%. Odds of a debut before 2027 are 74%. Traders still give Anthropic a 91% probability of beating OpenAI to market, a race Sam Altman has publicly downplayed in comments to Fortune.

The financials that’ll eventually surface are the reason small AI-tool buyers should care. Anthropic revenue jumped from roughly $4.7 billion in Q1 2026 to more than $11.5 billion in Q2, while compute spend climbed 65%, from $3.4 billion to $5.6 billion. Adjusted operating margin moved from -13% to a positive single-digit percentage. Enterprise customers spending $100,000-plus over trailing twelve months went from 1,500 at the end of 2025 to roughly 6,000 by end of Q2; more than 1,000 now spend over $1 million, and more than 100 spend over $10 million. Projected 2028 revenue: $190 billion to $200 billion.

The obligations behind those numbers are the tell. Anthropic’s SpaceX Colossus 1 deal in Memphis runs $1.25 billion a month through May 2029, terminable on 90 days’ notice by either party. It closed a $65 billion Series H in May at a $965 billion post-money and reported $120 billion to $130 billion in cash by early August. Amazon holds roughly 21% (about $33 billion), Alphabet about 15%, Salesforce about $5 billion.

The targeted valuation is $2 trillion, raising up to $100 billion. SpaceX’s June IPO raised $75 billion at $1.77 trillion. Anthropic wants to price above the most-watched listing of the year while still private, and every week EDGAR stays empty is a week the R&D Automation Index (published September 17, showing Claude now leads 26% of internal AI R&D versus under 1% in February) does the narrative work a prospectus can’t yet.

Sources

• https://forkast.news/the-anthropic-s-1-that-was-expected-after-labor-day-still-hasnt-arrived/
• https://www.anthropic.com/news/confidential-draft-s1-sec
• https://www.cnbc.com/2026/06/01/anthropic-ipo-s1-prospectus.html
• https://the-decoder.com/following-openai-anthropic-is-also-reportedly-postponing-its-ipo/
• https://time.com/partner-content/prediction-markets/prediction-markets-doubt-anthropic-s-ipo-timing/