The main filings of any US public company are the 10-K or annual report, 10-Q or quarterly report, DEF 14A or proxy report, and the 8-K or current events. These filings will give you an excellent overview of the company's business, financial health, legal affairs, and management.
Any of these filings can be amended after filing, so be sure to look for those if you are researching. They will be filed with the form number and a /A. (10-K/A, 10-Q/A, 8-K/A, etc.).
The SEC requires certain information be disclosed to investors in their filings. The 10-K requires a description of the company’s business, including its main products and services, what subsidiaries it owns, and what markets it operates in. Section 1A discusses risks the company faces, and Item 3 will disclose significant legal proceedings including litigation and government investigations. Financial data, a discussion and analysis from the management, along with accounting details are also included in the 10-K. Pay attention to the exhibits, too! They can attach legal contracts, identify subsidiaries, reveal loan data, and provide the company's bylaws.
"A company undertaking an IPO discloses required information in the registration statement, typically on Form S-1. Form S-1 and its amendments, which are denoted as S-1/A, are filed with the SEC and publicly available through the SEC’s EDGAR database at www. sec.gov/edgar/searchedgar/webusers.htm.
"Comment letters issued by the staff during the course of an IPO filing review are also made available on EDGAR, but they are not posted until at least 20 business days after the registration statement is declared effective.
"Most of a Form S-1 is comprised of the prospectus, which contains important information about the company. A new public company typically has no prior reporting history, and the information that can inform a decision to invest often can only be found in the prospectus, although, if it has sold securities in reliance on an exemption, the company may have filed one or more notices on Form D."
SOURCE: SEC's Investor Bulletin, "Investing in an IPO." See http://www.sec.gov/investor/alerts/ipo-investorbulletin.pdf
The Securities and Exchange Commission created the EDGAR database to allow the public better access to public filings, and to make it easier for companies to file their reports. The search is basic, and you will need to know the name of the company (or an identifying number or symbol) to access the filings. There are more than 20 million filings available going back to 1994.
If you need documents older than 1994, you can order the document from the SEC (scroll down to "How to Access or Request Records Not Accessible via SEC Website")
The SEC provides good background and guidance on how to search the database, what information is filed, and how to read the documents. See, for example:
There is so much information and access in this database, I am constantly finding new uses for it. The main page at the link above will take you to the basic search of EDGAR filings. Search the full text of filings, look for specific filers or forms, and limit to a date range for the most current or historical documents.
PRO TIP: Use the Advanced Search if you want to get focused results.
This chart shows the relationships between several companies. It is an example of the visualization of data possible using Rankandfiled.com.
Using the eXtensible Business Reporting Language (XBRL), RankAndFiled is able to extract data from across the financial tables of filers and display connections, comparisons, and analysis.
International companies are not required to file disclosures with the SEC, but many do. The forms are similar to those U.S. companies use, but have slightly different information and numbers. Most of the forms filed by non-U.S. companies will have the letter "F" in them. The annual report, for example, is filed on a 20-F.