Here are links to two databases that will give you market research information.
Passport GMID : All sorts of market reports covering lots of different markets in lots of different countries.
ABI/Inform : Click on the "Browse" link on the search page (top right-ish) and then select the type of report you would like. This database is also excellent for finding academic journal articles.
Any queries about these, then feel free to contact me, Keith, the Librarian.
Company information can be found from various sources. The most in depth information for UK & Irish companies can be found in the FAME database. Here you can search by industry, location, size of business (number of employees, turnover etc) and the typical result is the last 10 years accounts where submitted. All the information comes from Companies House so can be trusted.
If you are looking for a company and how it is placed within its market, or perhaps looking for strategic information such as a SWOT analysis, then Passport GMID is a good place to go.
UK Data Service provides preservation, dissemination, user support and training for an extensive range of key economic and social data, both quantitative and qualitative, spanning many disciplines and themes.
UK Government Statistics provides statistics covering a whole host of topics and themes.
Economic statistics, such as GDP's, inflation rates etc can be found in Passport GMID for almost every country in the World.