Article 29 confirms the general deductibility of interest expenditure. It states that, notwithstanding the rule against deducting costs related to exempt income in Article 28, interest is deductible in the Tax Period it is incurred. However, this deductibility is explicitly subject to the other general provisions of Article 28 (e.g., the 'wholly and exclusively' test) and, critically, the specific limitation rules detailed in Articles 30 and 31. This provision acts as a gateway, permitting interest as a deductible category before applying specific anti-avoidance caps and restrictions on related-party debt financing.