Swedish companies are registered at the Swedish Companies Registration Office.
You can access almost all registered information about a certain company at the Swedish Trade and Industry Register kept by the Companies Registration Office. There is a guide in English about how to use this register. However, the information is in Swedish only unfortunately.
You need a subscription (one time fee of SEK 600) to access the information and then you have to pay about SEK 6 to 8 for each page you look at.