When researching a company, it is important to know whether it is Public or Private.
PUBLIC COMPANIES sell shares of the company (stocks) to the general public, and are required to submit financial information and annual reports to the U.S. Securities and Exchange Commission. Public companies are therefore easier to research as a general rule of thumb.
PRIVATE COMPANIES do not sell publicly traded stocks and as a result, are not required to release as much information to the government or the general public They are therefore more challenging to research.
Link to Nasdaq will provide information on publicly traded companies.