# S-1

> The registration statement a company files to offer securities to the public, most often for an initial public offering.

Updated Oct 17, 2026.

Form S-1 is the registration statement a US company files under the Securities Act of 1933 to offer securities to the public. It is most often seen before an initial public offering (IPO). It contains the prospectus that investors are given.

## What is in it

The prospectus summary, risk factors, use of proceeds, dilution, capitalization, MD&A, a description of the business, management and pay, the principal shareholders, and audited financial statements.

## How it moves

- Many companies first submit a draft confidentially. The S-1 must be filed publicly at least 15 days before the company starts marketing the offering.
- The SEC staff comment, and the company answers with amendments (`S-1/A`). Comment letters and responses are released on EDGAR later.
- When the SEC declares the registration effective, the offering can go ahead. The final prospectus is filed under Rule 424(b), often as a `424B4`.

## Reading it

For a new public company, the S-1 is usually the longest and most candid document it will publish. Risk factors and the description of how insiders and early investors hold and can sell their shares (lock-ups, share classes, voting control) are worth reading in full.

## Related terms

- [10-K](/glossary/10-k.md)
- [XBRL](/glossary/xbrl.md)
- [Filer category](/glossary/filer-category.md)
- [Amendment](/glossary/amendment.md)

All terms: [/glossary.md](/glossary.md)