In its notice of 14 September 2026, the Autoridade Tributária encourages submission of forms and payment of monthly taxes between the first and tenth days of the month. This recommendation responds to instability and temporary interruptions in the tax system reported by the administration.
The practical benefit is to leave time to check the return and payment, resolve a difficulty or resume an interrupted transaction. The recommendation to act early must not be turned into creation of a new statutory deadline on the tenth day.
Acting early usefully covers both operations: submitting the form sooner would leave the problem unresolved if payment remained unconfirmed. Reconciling the period, return and payment would help identify an incomplete operation before the deadline. The resulting margin addresses the technical risk reported; it is neither a tolerance for subsequent lateness nor a guarantee against all penalties.
The administration continues to tie compliance to statutory deadlines and warns of penalties for late filing. A business therefore still needs to identify the obligation concerned and check its proper completion. A mere login attempt establishes neither completed filing nor confirmed payment.