Short answer
Skip the opening story and go straight to the financial tables, the cash flow statement, the contractual obligations, the risk factors, the voting structure and the lock-up section. An S-1 is the document a company files with the US Securities and Exchange Commission before selling shares to the public, and it runs to hundreds of pages, so that order gets you to what matters first.
Follow-up question What can an S-1 not tell you?
An IPO, or initial public offering, is the first time a company sells its shares to the general public. In the United States, it must first register with the Securities and Exchange Commission (SEC), and the main registration form is the S-1. The SEC does not judge whether the shares are a good deal. As its investor site explains, the point is to give people the information to judge for themselves.
Two recent filings show what this looks like in AI: SpaceX, which owns xAI, published on May 20, 2026, and Anthropic on October 26, 2026. Both are free on the SEC's EDGAR database. Each runs to hundreds of pages, so you need a route through it.
Why parts of it are blank
Open Anthropic's filing and you will find gaps such as "aggregate committed spend of more than $ ," with no number. This is normal for a first public S-1. The share count, price range and some other figures are added in later amendments, close to the sale. The final version is called a prospectus.
A confidential step usually comes first: companies can submit a draft that the public does not see. OpenAI said in June 2026 that it had done this, without giving a size or a timeline, so there is nothing of its to read yet.
A reading route in six stops
| Stop | Search for | What you learn |
|---|---|---|
| 1 | "Summary Consolidated Financial" | Revenue, costs, losses over several years |
| 2 | "Net cash provided by" | Whether cash really came in or out |
| 3 | "Contractual Obligations" | What it has promised to pay |
| 4 | "Risk Factors" | What its lawyers fear, in detail |
| 5 | "voting power" | Who controls the company |
| 6 | "lock-up" | When insiders can sell |
Stop 1: the tables. Read across the columns, not just the latest one. Anthropic's revenue goes $41 million, $386 million, $4.6 billion, then $16.3 billion for half of 2026. Now find the odd line: a $72.4 billion charge for "change in fair value," which explains most of the $80.7 billion net loss. That charge involves no cash. When a number looks shocking, read its footnote.
Stop 2: cash. Anthropic's operations brought in $3.9 billion in the six months, but the filing credits part of that to payment timing. Its financing brought in $110.8 billion, which is why a company with an operating loss can have so much cash.
Stop 3: promises. AI filings differ from most in this section. Anthropic's lists at least $114.5 billion to Google and $110 billion to Amazon, among others. SpaceX's discloses that xAI's lessor arrangements carry about $20.2 billion in payments. Our guide to compute commitments explains how to read them.
Stop 4: risks. Most risk factors are boilerplate. Look for sentences with numbers or specifics. Anthropic discloses that 5% to 7% of nine-month revenue came from customers it later found to be violating its policies and that many top customers can cut spending at any time. SpaceX warns that its AI segment is capital intensive and has large operating losses.
Stop 5: control. Buying a share does not always buy a real vote. Elon Musk is expected to keep majority voting control of SpaceX, making it a "controlled company" that can skip some Nasdaq governance rules. At Anthropic, a Class F share held by an entity called Founder LLC gets 50.1% of the votes on most matters, while a separate trust, the Long-Term Benefit Trust, generally elects a majority of the board. The filing warns that those holders' interests may differ from those of ordinary shareholders.
Stop 6: the lock-up. A lock-up is an agreement that insiders will not sell for a set period after the IPO, so that a flood of shares does not hit the market immediately. Anthropic's has two tiers. Most holders are released at the earlier of 180 days or shortly after results for the quarter ending March 31, 2027. Co-founders and large holders wait until the earlier of 365 days or shortly after results for the quarter ending September 30, 2027. The underwriters, Goldman Sachs and Morgan Stanley, may release shares sooner. Watch those dates, because new supply can move the price.
Words that trip people up
| Term | Plain meaning |
|---|---|
| Non-GAAP or "adjusted" | A figure that departs from standard accounting; read what was removed |
| Run-rate | Recent sales annualized, not sales earned |
| Net revenue retention | How much existing customers spend now against a year ago; Anthropic reports about 900% |
| Related party | A deal with an insider or a major holder |
| Use of proceeds | What the new money is for, often stated in very general terms |
| Remaining performance obligations | Revenue under contract but not yet recognized |
Getting an AI model to help
A filing is an ideal job for an AI assistant, as long as you check what it tells you. Download the document as text, then ask for quotes you can look up.
You are helping me read an S-1 filing, which I have attached. Using only this document:
1. List total revenue, operating loss, net loss and cash from operations for each period shown.
2. List every compute or infrastructure commitment with a dollar figure, its counterparty and its end date.
3. Who controls the votes after the offering?
4. What are the lock-up periods?
Quote the exact sentence for each answer. If a figure is blank in the filing, say "blank" instead of estimating.Then search for each quote in the original. Models make mistakes, especially with tables and with columns that change period.
Try it: Open the SpaceX or Anthropic filing on EDGAR, search for "lock-up," and write down who is covered and for how long. Then repeat with the "Contractual Obligations" section.
What can an S-1 not tell you?
It cannot tell you what a share is worth. That depends on the price, which is often blank at first, and on a future nobody knows. It also reflects the past: Anthropic's audited and unaudited numbers end at June 30, 2026, with a few later updates, and quarterly results reported to investors elsewhere are not the same as filed numbers.
It tells you the company's own account of its competitive position. The business section is written to attract buyers, and "the deepest concentration of AI research talent in the world," a phrase from Anthropic's filing, is a claim rather than a measurement. Check such claims with outside evidence, such as independent model evaluations.
And it cannot tell you whether you should buy. This guide is about reading, and it offers no recommendation on any share. If you are considering an investment, a licensed adviser can look at your own situation.
Sources
- Form S-1 registration statement, Anthropic, PBC — Anthropic / US SEC, October 26, 2026
- Form S-1 registration statement, Space Exploration Technologies Corp. — SpaceX / US SEC, May 20, 2026
- Registration Under the Securities Act of 1933 — US SEC, Investor.gov
From the Guide to Artificial Intelligence, by Robert Scales, published by Holistic Hybrid Inc. Share and adapt it under CC BY-NC-SA 4.0: credit the guide, link to https://guidetoartificialintelligence.com/en/learn/how-to-read-ai-ipo-filing-s1/, no commercial use without permission, and keep the same licence.