On 29 January 2014, the Belgian Constitutional Court ruled on the compatibility of the Belgian foreign tax credit rules with the Belgian constitution. The Constitutional Court ruled that denying the carry-forward or carry-back of an unused foreign tax credit is not unconstitutional. The same goes for not refunding an unused foreign tax credit. However, including a foreign tax credit that has not actually been credited was deemed unconstitutional by the Constitutional Court.
This means the Belgian government is not required to allow Belgian taxable entities to carry-back or carry-forward a foreign tax credit that has not been (fully) used because of an insufficient taxable base. However, an unused foreign tax credit can no longer be treated as a disallowed expense which would result in more profit i.e. less tax losses.