1. Perception of delays in work performance
Regulations: Art. 14.2 b) Law Income Tax
A supplementary self-assessment must be submitted when, due to justified circumstances not attributable to the taxpayer, income derived from work is received in tax periods other than those in which it was due. These amounts must be attributed to the tax periods in which they were payable, and, where appropriate, the corresponding supplementary self-assessment must be made.
See in this regard the section " Temporal imputation of employment income " in Chapter 3.
This supplementary self-assessment, which will not entail any penalty or late payment interest or any surcharge, must be submitted within the period between the date on which the arrears are perceived and the end of the immediately following period for declarations for the IRPF .
Thus, if the arrears are received between January 1, 2021 and the start of the period for filing the IRPF returns corresponding to the 2020 fiscal year, the supplementary self-assessment must be submitted in that year before the end of the filing period (until June 30, 2021), unless they are arrears from the 2020 fiscal year, in which case they will be included in the self-assessment for that fiscal year.
For arrears received after the end of the deadline for filing returns for the 2020 fiscal year (June 30, 2021), the supplementary self-assessment must be submitted within the period between the receipt of the arrears and the end of the deadline for filing returns for the 2021 fiscal year.
Note: If the supplementary declaration responds to this circumstance, the taxpayer must mark with an "X" the box [108] of the "Supplementary declaration" section of the declaration.