In January, modify your provisional prorated amount

If your company pays taxes under the VAT prorated regime, until the end of 2026 you will not know what your final prorated percentage for the year will be, so in previous declarations you must apply the 2025 prorated amount provisionally. As for the final 2026 declaration (which you will submit in January 2027), you must regularize the differences (once you know the final prorated amount).

Therefore, if you anticipate that the final 2026 prorated amount will be higher than that of 2025, during this month of January you can request a change in the provisional prorated amount to avoid advancing money to the Tax Office.   If the circumstances that motivate the change occur during the year, you can also request this change until the end of the following month after those circumstances take place.