1. A national regulatory authority may, in accordance with Article 68, impose obligations for accounting separation in relation to specified activities related to interconnection or access.

In particular, a national regulatory authority may require a vertically integrated undertaking to make transparent its wholesale prices and its internal transfer prices, inter alia to ensure compliance where there is an obligation of non-discrimination under Article 70 or, where necessary, to prevent unfair cross-subsidy. National regulatory authorities may specify the format and accounting methodology to be used.

2. Without prejudice to Article 20, to facilitate the verification of compliance with obligations of transparency and non-discrimination, national regulatory authorities shall have the power to require that accounting records, including data on revenues received from third parties, are provided on request. National regulatory authorities may publish information that would contribute to an open and competitive market, while complying with Union and national rules on commercial confidentiality.