Documents filed with the SEC are likely to be the most accessible but also going to provide the most information on public companies.

When it comes to company filing documents, finding them is likely a combination of electronic sources and microfiche sources. No sources are 100% complete. Between our microfiche sets and the databases, the Library does have a good collection that does have some overlap. However, these sources may be harder to find or access around the country.

• If you are looking for older for SEC filings that date after 1994 the EDGAR system is free on the SEC's website. Prior to that you have to look to elsewhere. The Library has a microfiche set but you will need the print index to find the filings themselves.  There are several volumes by year and the entries are alphabetical by company. Not all filings for all companies are included. The set includes 10Ks/annual reports to shareholders, proxies, 10Qs, and some 8Ks.
• There are vendors like Thomson Reuters and Westlaw that do have databases with SEC filings and annual reports (the Library doesn't have access) but access to them may be limited.
• The Library does have access to two relevant databases - Proquest Historical Annual Reports and Mergent Archives, both of which have annual reports while Mergent also has archival 10Ks back to the early 1960's.
• The Library has several sets of microfiche annual reports to shareholders and links to the inventories are below.

Also, if the public company that is highly regulated try government sources. For example, banks are regulated and the FDIC has collects detailed financial information for decades. Other agencies like the Civil Aeronautics Board has the Quarterly Report of Air Carrier Financial Statistics and the Handbook of Airline Statistics for United States certified air carriers that contains some pretty detailed financial data as well as data specific to air travel like passenger v. cargo/mail, some aircraft information, some destination information, etc.

Below are databases and open access resources. The subscription resources marked with a padlock are available to researchers on-site at the Library of Congress. If you are unable to visit the Library, you may be able to access these resources through your local public or academic library.

These are big publishers that have been around for many years and publish similar types of publications. The titles included here are titles that are were widely purchased by institutions around the country and may be more likely to be more common and possibly more accessible in terms of historical volumes.

Each publishes many different titles, but all are good for researching various aspects of public companies.  The most comprehensive and important sets produced are the Manuals. Each of these are organized similarly by having volumes covering: railroads (S&P's version goes back much longer), banking/finance, industrials, utilities. The Manuals were titles that many libraries subscribed to but may not have kept older volumes. Each has similar information - though what was included changed and grew over time. Mostly there is financial information, some history, officers, subsidiaries, and other similar types of information.

One other area that may be of interest are dividends and both published titles related to reporting dividends. S&P published the annual Dividend Record and Moody's/Mergent published one monthly (they also published an annual).

The Standard and Poor's Register also seen as Standard & Poor's Register of Corporations, Directors and Executives is good for short and introductory information that has been a widely available, though holds for the older editions may be harder to find.

There are many titles that can be used for research but there are a few titles to mention specifically but several may be harder to access for various reasons.