Form S-1 is a mandatory filing with the Securities and Exchange Commission. The SEC requires a Form S-1 for the initial registration of new securities for public companies based in the United States while foreign issuers of securities in the U.S. use a similar alternative SEC Form F-1. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.