It largely depends on what type of information you are looking for.
If it is related to the financial accounts e.g profit, turnover, balances sheets then you probably need to use one of our databases fron Bureau Van Djik. Further details are available at: http://libguides.ncl.ac.uk/business/companyinfo
Within EBSCO you can also access company reports although the focus is mainly American you can find information on global companies.
Nexis also provides information for over 100 million companies. They pull data from a number of key sources including Dun & Bradstreet, Hoover's Company Profiles, Mergent, ICC Directory of UK Companies and ICC Financial Analysis Reports. Select Company profiles once you are logged in the database.
The Company Information guide lists other places you might also want to consider using depending on the type of information you are looking for.