On 15 March 2013, the Belgian Supreme Court (Cour de Cassation/Hof van Cassatie) decided two cases (recently published) on the avoidance of double taxation on interest under the former Belgium - United States Income Tax Treaty (1970) (as amended through 1987). Details of the case are summarized below. (a) Facts. Belgian companies received interest from US companies under the 1970 treaty with the United States. The receiving Belgian companies had debts. Therefore, the amount of the fixed credit for the withholding tax on interest was reduced as it was multiplied with a debt financing coefficient (see below). (b) Legal background....