In general, foreign individuals can purchase and own real estate (land or buildings) in Bulgaria only if they buy through the medium of a Bulgarian limited company.

A person buying an apartment does not need to do this. This is because you only ‘own’ your apartment, not the land it is built upon. You need not be too worried about this. Your rights over it continue for ever. Even if the property burns down you are allowed to rebuild. It is just that it is not, officially, classified as the ownership of land. 

Some apartments are sold with a share in the land upon which they are built. In this case you will need to own, at least the land, via a Bulgarian company.

 You can always, as a foreign individual, register a company in Bulgaria and buy the  property through that company. ‘a company owned by a foreign person in the Bulgaria is considered to be a Bulgarian legal entity and, as such, may acquire real estate ownership rights without any restriction- whether the real estate is acquired for business or for some other purpose. This applies even if the company is 100% foreign owned. All the necessary procedures for establishing the company can be completed within approximately one month.