"A ticker symbol is an arrangement of characters (usually letters) representing a particular security listed on an exchange or otherwise traded publicly. When a company issues securities to the public marketplace, it selects an available ticker symbol for its securities which investors use to place trade orders. Every listed security has a unique ticker symbol, facilitating the vast array of trade orders that flow through the financial markets every day."
Source: Investopedia

Many of the resources in this guide will identify ticker symbols, but one of the quickest ways to find a ticker symbol is to use a website like Yahoo Finance or CNBC.

Understanding how a company is organized is the first step in company research. This information guides the researcher to the right types of sources and sets the appropriate expectation of how much information can be found.

The amount of information available varies greatly depending on the type of company. Most company databases have information on public companies, but there are sources that specialize in private company information, too.

To start, use a directory to determine whether a company is public, private, non-profit, subsidiary or international.

Public
Public companies sell shares on a stock exchange and they have specific requirements to disclose information to their shareholders and the public.There is a great deal of information available on public companies- SEC filings, annual reports, analyst reports, news article, books and case studies.

Private
Information about privately-held companies can be limited because these types of companies do not have the same filing requirements as public companies. Information on private companies is usually limited to brief information in directories, news stories, and sometimes books. All 50 states make some level of corporate and business filings available online.

International
The amount of information on international companies varies. If the company trades on the U.S. exchanges it must file annual reports (20-F) with the SEC. Other information can be found in directories, databases, newspapers and magazines.

Non-Profit
Finances and other general information can be found in Form 990 which nonprofits must file with the IRS annually. See Grantspace.org's KnowledgeBase:  Where Can I find an organization's Form 990 or 990-PF? Some information can also be found in newspaper and journal articles.

Subsidiary
A subsidiary is part of a larger parent company.  Parent companies do not necessarily disclose subsidiary information separately.  Information is usually interwoven within parent company profiles and financials.  Some parent companies may provide information on subsidiaries via the corporate website.  Other information may be located through news articles.