The most anticipated IPO of the decade just got a reality check. Some current and prospective investors in Anthropic's upcoming listing discussed a valuation of around $1.5 trillion at the company's investor day in San Francisco this week, according to Reuters, a significant step down from the roughly $2 trillion valuation previously expected for the November share sale. The $500 billion gap rattled AI-linked stocks through the week and fed the broader tech selloff that dragged the Nasdaq down 2.2 percent on Friday.

The disappointment is striking because the numbers themselves were strong. Anthropic told prospective investors that third-quarter revenue jumped 45 percent to $16.8 billion, up from $11.6 billion in the second quarter and $4.7 billion in the first, and that the company was profitable on an adjusted basis during the quarter. For a company that lost more than $8 billion on an operating basis in 2025, adjusted profitability is a genuine milestone. But investors focused on the deceleration: revenue more than doubled from Q1 to Q2, so the 45 percent sequential growth in Q3 felt like a comedown even at this scale.

The valuation debate is really a debate about growth rates, not revenue levels. At $16.8 billion a quarter, annualized revenue is roughly $67 billion, so a $2 trillion valuation implies a price-to-sales multiple of about 30, rich but not absurd for a high-growth AI company. The problem is the trajectory: large clients like Meta and Microsoft are increasingly leaning on AI models they build themselves rather than buying from Anthropic, and the company has cut back on distillation revenue, which had contributed 5 to 7 percent of sales. Pricing pressure is intensifying too, with Claude Haiku 5.5 priced about 75 percent below its predecessor as low-cost Chinese labs compete aggressively.

The cost side of the AI trade is what truly worries the market. Anthropic has committed at least $518 billion over the next decade to cloud services, computing, and infrastructure, a staggering capital program that requires the IPO to fund. The cooler investor reception speaks to broader concerns about the ballooning cost of financing AI across the industry, the same anxiety that has weighed on chip stocks all week. A weak reception for the Anthropic listing could weigh on the wider AI market, whose near-term prospects investors see as hinging on the share sale's success, followed by OpenAI's potential listing next year. On the other hand, the episode shows how quickly the market reprices growth stories when the second derivative turns, a dynamic familiar to anyone who has studied human analysts versus algorithms when news breaks. Before buying into the IPO narrative, check how accurate AI systems are in 2026 at forecasting outcomes, and remember that the best time to price an asset is rarely when everyone already agrees it is a winner.

Regulatory clouds are gathering as well. The Federal Trade Commission confirmed it has subpoenaed Anthropic and OpenAI over potential consumer protection violations, adding legal overhang to the IPO marketing. The listing is expected after the November 3 midterm elections, with formal marketing possibly beginning the week of November 9, which would put a trading debut before Thanksgiving within reach. Amazon and Alphabet, both investors and compute suppliers, have their own stakes in a successful listing, since a public prospectus will reveal far more about Anthropic's unit economics and competitive moat.

For investors, the lesson cuts both ways. On one hand, $1.5 trillion would still rank among the largest IPOs in history, and adjusted profitability at this revenue scale is a real achievement that few AI labs can claim. On the other hand, the episode shows how quickly markets reprice growth stories when the second derivative turns negative. With formal IPO marketing possibly starting the week of November 9, the company has limited time to convince investors that 45 percent growth at this scale deserves a premium multiple.