International tax matters arise as soon as another country becomes involved in any way. The company suddenly becomes subject not only to Swedish tax regulations, but also to the tax regulations of the other country in question, plus any agreements between the two countries.
Every country has its own tax base and compliance is monitored carefully. Conflicts arise occasionally between different regulations in different countries, including double-taxation. The best-case scenario is to take advantage of different benefits offered by the tax systems of the countries concerned.