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Edgewise Consulting, Lda

Tax calendar: the deadlines not to miss before year end

From payments on account to withholding tax, what needs to be in order before closing 2026

Tax forms, calculator and magnifying glass on a desk

Year end brings together tax and social security obligations that, if missed, lead to fines and interest. Here is what companies need to plan for.

In December companies combine the year-end close with their recurring obligations. Planning ahead avoids penalties and, above all, cash-flow surprises.

Obligations that repeat every month

  • VAT: filing and payment deadlines depend on your regime. Monthly filers generally have until the 20th of the second following month; quarterly filers until the 15th of the second month after the quarter.
  • Withholding tax (personal and corporate income tax): payment is due by the 20th of the month following the one in which it was withheld.
  • Social security: the remuneration return and the contributions are also due in the following month.

What counts in December

  • Last corporate income tax payment on account, on 15 December, for the companies concerned.
  • Christmas bonus, payable by 15 December, with the related withholdings and contributions.
  • Balance review: customers, suppliers and bank reconciliations, so that January starts with clean books.
  • Inventories and impairments: the right moment to decide on bad debts and adjustments.

How to get organised

  1. Build a map of all dates and who is responsible for each.
  2. Work out early how the payment on account and the Christmas bonus affect your cash flow.
  3. Ask your accountant for a result simulation before closing, while you can still decide.

Deadlines may change with current legislation and with your regime. Always confirm your company's specific situation with our team.