The purpose of this taxis to obtain income in Spain by non-residents. The taxpayers are natural persons and legal entities that obtain income in Spain. The law contains many specifications to determine when it is understood that an income is obtained in Spain. The most important thing is that the tax has, in turn, two different ways of being taxed within this tribute, completely different:
1) Income obtained through a permanent establishment in Spain.
The law means that a person has a permanent establishment here when you work facilities or premises, or acting through a third party permanently.
2) The income obtained in Spain without a permanent establishment in Spain.
It is a purely objective tax when the income obtained cause, pay the tax and is released from the obligation without further delay. Taxation is separated for each accrual of income. The important thing is to determine when an income obtained in Spain means (studios, artists and athletes, dividends from resident entities, etc.).
In this tax retention it is very important. In the case of transfer of property, for example, retention is 3, and the purchaser is required to submit to the Spanish tax system is satisfied sale. Retention here is crucial, because it allows to control the payment. Non-residents must file returns unless they have supported retention, in which case the tax is limited to the supported retention.