 This "chartered" or "foral" contract entails true financial autonomy.Since they collect almost all taxes, they send to the central government a pre-arranged amount known as "cupo", "quota" or "aportación", "contribution", and the treaty whereby this system is recognized is known as "concierto", "treaty", or "convenio", "pact".Hence they are also said to have "concierto económico", an "economic treaty".