The S-1 and the IPO
The registration statement filed before a company sells shares publicly for the first time. It is the most detailed document a company ever produces about itself.
MadStockAlerts Research · Updated August 28, 2026
What to take away
- Form S-1 is the first comprehensive public disclosure a company makes.
- The use-of-proceeds section says what the money is for.
- Amendments track the SEC review and the eventual price range.
- Lock-up expiry dates are disclosed and are a scheduled increase in the public float.
- Primary and secondary shares in an offering mean very different things.
MAD Academy Training Video · 0:45
The First Time a Company Explains Itself
An S-1 is the most complete document a company ever files, because it is the first and everything has to be established from scratch.
This lesson is part of a Stock Alerts + Tools plan.
Why it is worth reading in full
A company filing an S-1 has never had to disclose anything before. The document therefore explains the business from first principles, in far more detail than any later Form 10-K will, because later filings assume the reader already knows.
It is also written to sell. That is not a criticism, but it does mean the prose is the most favourable version of the company that its lawyers would permit, and the risk factors are the corrective the same lawyers insisted on.
The sections that carry the most
| Section | What it reveals |
|---|---|
| Use of proceeds | Whether the money funds growth, repays debt, or cashes out existing holders |
| Capitalization and dilution | What new buyers pay against what insiders paid |
| Principal and selling stockholders | Who is selling into the offering |
| Management's discussion | The financial history, usually two to three years |
| Risk factors | The first, and often the most candid, version a company ever writes |
| Underwriting | The syndicate, the fees, and the lock-up terms |
The distinction between primary and secondary shares in an offering matters. Primary shares are new, and the money goes to the company. Secondary shares are existing holders selling, and the money goes to them. An offering that is largely secondary is a liquidity event for insiders rather than a capital raise.
The dilution table
Every S-1 carries a table showing the difference between what new public buyers pay per share and the average price existing holders paid. The gap is frequently enormous, and it is disclosed because regulators require it to be.
It is not by itself an argument against the offering: early investors took risk that public buyers are not taking. It is a fact about the transaction that the marketing materials will not lead with, and it is on a numbered page.
Scroll the chart sideways to see all of it.
The amendment trail and lock-ups
S-1/A amendments are filed through the SEC review process. Comparing successive amendments shows what changed: added risk factors, revised financials, and eventually the price range and share count. A price range revised downward before pricing is a visible piece of information.
Insiders typically agree not to sell for a set period after listing, commonly 180 days. The date is disclosed, so the market knows in advance when a large block of shares becomes eligible to be sold, which is a scheduled expansion of the float.
The mechanics between filing and trading
The registration statement is the beginning of a process with several defined stages, and each produces its own filing. Knowing the sequence makes it possible to tell where a deal has reached from the documents alone.
- 1Confidential submissionEmerging growth companies may submit a draft non-publicly. It appears later as a DRS filing, and comparing it with the public S-1 shows what changed under staff review.
- 2The public S-1Filed with the price range and share count left blank in the first version.
- 3AmendmentsS-1/A filings, adding the range, then narrowing it. The direction of the revisions is a reasonable read on demand.
- 4Pricing and the 424B4The final prospectus, filed after pricing, contains the actual price and the final share count.
- 5Lock-up expiryTypically 180 days later, when insiders and pre-IPO holders become able to sell.
The over-allotment option, commonly called the greenshoe, allows underwriters to sell up to fifteen percent more shares than the base deal. Its exercise is disclosed and it changes the free float, which matters for anything that depends on how many shares are actually available.
Reading the risk factors in an S-1
Risk factors in an established company's 10-K are largely copied forward and are read for what changed. In an S-1 there is no prior version, and the section is the first and most complete statement the company has ever made about what could go wrong.
- Customer concentration is disclosed here and is frequently far higher than the marketing suggests.
- Dependence on a single platform, supplier or distribution channel is stated plainly, including where the counterparty is also a competitor.
- Whether the company has ever been profitable, and whether it expects to be, is stated in terms lawyers chose rather than terms a founder would.
- Dual-class share structures and their consequences for public holders appear here in full.
- Going-concern language, where it exists, is the most consequential sentence in the document.
The section is also the best available guide to the accounting. Where revenue recognition, key metrics or non-GAAP definitions are unusual, the risk factors and the accompanying discussion say so, because failing to say so creates liability.
Company-defined metrics deserve the same scrutiny. Terms such as active users, bookings or annual recurring revenue are defined by the company in the prospectus, and the definition is where the number is made.