Anthropic’s prospectus runs more than 300 pages. The research on IPO returns is shorter.

Anthropic filed a registration statement on Form S-1 on October 26, 2026 for an initial public offering of Class A shares, and the Wall Street Journal’s editorial board describes the prospectus as more than 300 pages long.[1][2] The share count and price range have not been set, and the Journal reported that the company is aiming to go public as soon as the week of Nov. 16, according to people familiar with the matter, though the timing could change.[1][3] A document written for professional investors now sits one browser window away from a teenager with a brokerage account, as an earlier note documented, so the filing and the research on IPO returns are both publicly available to read before any trade.

What the filing reports

According to the Journal’s editorial board, Anthropic reported $16.3 billion in revenue for the first half of 2026, up from $1.2 billion in the same period of 2025, and estimates at least $417 billion in future payments, mostly for computing and infrastructure.[2]

What a market-size claim measures

A total addressable market is the revenue a company could reach if it captured all demand.[4] It is a ceiling on the opportunity. The Journal reported that the filing suggests a $40 trillion annual opportunity, based on the economic value of knowledge work, which tops the $28.5 trillion SpaceX estimated earlier this year.[4] The reporters note that companies build these figures in different ways, from counting customers and their spending to measuring the value of labor.[4]

What IPO return research shows

Jay Ritter of the University of Florida tracks IPO returns from the first closing price, so the first-day jump is excluded. Across 9,253 IPOs from 1980 to 2024, the average three-year return trailed the market by 20.5%.

For the 866 IPOs of companies with at least $1 billion in pre-issue sales, the gap was 2.1%, close to the market.[5] Size narrows the gap, and the large-company figure is still below the market.

The weakest stretch of the average IPO’s first year is the second half. Ritter’s data show IPOs trailing size-matched firms by 0.6 percentage points in the first six months and 5.5 points in the next six.[5]

Separately, Laura Field and Gordon Hanka studied 1,948 lock-up agreements, the contracts that bar insiders from selling shares for a set period, and found an average three-day abnormal return of negative 1.5% when lock-ups expired, along with a permanent 40% increase in trading volume.[6]

The two studies use different samples, and this note does not link them. Both are averages across thousands of companies and say nothing about any single IPO.

Where young investors already stand

Research on retail investors has long tied gambling-style preferences to what people buy. Alok Kumar’s analysis of brokerage accounts found that individual investors favor stocks with lottery-type features, and that poor, young, less educated men invest more in them and underperform more, a pattern he read as gambling attitudes showing up in stock choices.[7] His data covers 1991 to 1996.

Prediction markets are the newer layer. In a 2026 Ipsos poll for the American Institute for Boys and Men, 26% of men ages 18 to 24 had used a sports betting, daily fantasy sports, prediction market or gambling platform in the past six months, against 14% of all adults. Among all young men surveyed, 47% called prediction market contracts closer to gambling and 10% closer to investing, and 61% of all adults put them closer to gambling, whatever the platforms call them.[8]

Polymarket and Kalshi both list contracts on Anthropic’s IPO, and Polymarket’s contract on IPO timing had $6 million traded by October 28.[9] The poll did not ask about IPOs, and the contracts are wagers on outcomes, not shares of the company.

Reading before trading

A prospectus is free, dated and filed with the SEC, which makes it among the best-documented sources a first-time buyer will be offered. Reading one, judging a market-size claim and knowing what a lock-up schedule means take practice.

FinBizify builds lessons from real companies, real dollar amounts and public filings so a teenager can understand how these large companies operate when they’re younger and have background education to make the call on future financial decisions.

Sources

1. Anthropic, “Anthropic files S-1 with the SEC for proposed initial public offering,” October 26, 2026. https://www.anthropic.com/news/s1-sec

2. The Editorial Board, “Anthropic’s Big IPO Gamble,” The Wall Street Journal, October 26, 2026. https://www.wsj.com/opinion/anthropic-ipo-investors-regulation-dario-amodei-c7339185

3. “Anthropic Unveils Paperwork for Blockbuster IPO,” The Wall Street Journal, October 26, 2026. https://www.wsj.com/tech/anthropic-unveils-paperwork-for-blockbuster-ipo-291a684b

4. Anvee Bhutani and Nate Rattner, “See How Anthropic Arrived at Its Mind-Boggling $40 Trillion Market Opportunity,” The Wall Street Journal, October 27, 2026. https://www.wsj.com/tech/ai/see-how-anthropic-arrived-at-its-mind-boggling-40-trillion-market-opportunity-948c56a0

5. Jay R. Ritter, “Initial Public Offerings: Updated Long-run Statistics,” University of Florida, October 5, 2026 (Tables 16a and 20). https://site.warrington.ufl.edu/ritter/files/IPOs-long-run-returns-on-IPOs.pdf

6. Laura Casares Field and Gordon Hanka, “The Expiration of IPO Share Lockups,” Journal of Finance 56(2), April 2001. https://ideas.repec.org/a/bla/jfinan/v56y2001i2p471-500.html

7. Alok Kumar, “Who Gambles in the Stock Market?,” University of Notre Dame working paper, October 30, 2005. https://www.anderson.ucla.edu/documents/areas/fac/finance/kumarwhogambles.pdf

8. American Institute for Boys and Men and Ipsos, “Most Americans see prediction markets as more like gambling than investing,” March 17, 2026 (poll fielded February 27 to March 1, 2026; 2,363 adults, 447 men ages 18 to 24). https://aibm.org/research/most-americans-see-prediction-markets-as-more-like-gambling-than-investing-new-aibm-ipsos-poll-finds/

9. “Prediction market bets set the tone for Anthropic’s much-awaited IPO,” The Globe and Mail, October 28, 2026. https://www.theglobeandmail.com/business/article-prediction-market-bets-set-the-tone-for-anthropics-much-awaited-ipo/