a) Intermediaries, i.e. any person that designs, markets, organises or makes available for implementation or manages the implementation of a reportable cross-border arrangement. It also means any person that, having regard to the relevant facts and circumstances and based on available information and the relevant expertise and understanding required to provide such services, knows or could be reasonably expected to know that they have undertaken to provide, directly or by means of other persons, aid, assistance or advice with respect to designing, marketing, organising, making available for implementation or managing the implementation of a reportable cross-border arrangement.  

b) Relevant taxpayer, i.e. any person to whom a reportable cross-border arrangement is made available for implementation, or who is ready to implement a reportable cross-border arrangement or has implemented the first step of such an arrangement.