Artikel 26

1. The competent authorities of the States shall exchange such information (being information which such authorities have in proper order at their disposal) as is necessary for the carrying out of this Convention, in particular for the prevention of fraud. Any information so exchanged shall be treated as secret and shall not be disclosed to any persons or authorities other than those, including a court, concerned with the assessment or collection of, or the determination of appeals in relation to, the taxes which are the subject of this Convention.
2. In no case shall the provisions of paragraph 1 be construed so as to impose on one of the States the obligation:
a) to carry out administrative measures at variance with the laws or the administrative practice of that or of the other State;
b) to supply particulars which are not obtainable under the laws or in the normal course of the administration of that or of the other State;
c) to supply information which would disclose any trade, business, industrial, commercial or professional secret or trade process, or information, the disclosure of which would be contrary to public policy.