IPO pipeline

A US initial public offering leaves a paper trail on EDGAR that is public long before the roadshow: an S-1 (or F-1 for a foreign issuer) when the company first files, amendments as the SEC comments and the price range is set, an EFFECT notice when the SEC declares the registration effective, and a 424B4 prospectus with the final price on the morning of pricing. A company that gives up files an RW to withdraw.

This page lists those filings as they land and marks which filers are new to the market and which are already listed, so IPO candidates sit apart from the follow-on and resale registrations that listed companies also file on S-1. Blank-check companies (SPACs) count as new issuers.

The pricing prospectus (424B4) is the event. Everything before it is a pipeline that can stall for months; the count of new S-1s against the count of pricings is the simplest read on whether the IPO window is open.