Temporary imputation of work income
Regulations: Art. 14.1 a) Law Personal Income Tax
Work income, both income and expenses, is allocated to the tax period in which it is payable by the recipient.
A. Returns pending judicial resolution
Regulations: Art. 14.2 a) Law Personal Income Tax
When all or part of an income has not been paid, because the determination of the right to its collection or its amount is pending a judicial resolution, the unpaid amounts will be attributed to the tax period in which it becomes final.
Notwithstanding the above, if the work income is not received in the year in which the judicial resolution has become final, it will not be appropriate to include it in the declaration corresponding to said year, but rather, by application of the rules relating to "arrears" discussed below, they must be declared through the complementary self-assessment corresponding to the year in which the judicial resolution became final. Said declaration must be made within the period between the date on which the income is received and the end of the immediately following period for submitting declarations for the Personal Income Tax .
In any case, by application of this special rule of temporal imputation, if income that corresponds to a generation period greater than two years is included in the declaration of a fiscal year, the reducing percentage of 30 percent will be applicable to them.
Regulations: Art. 14.2 b) Law Personal Income Tax
When, due to justified circumstances not attributable to the taxpayer, income derived from work is received in tax periods other than those in which they were payable, they must be declared when they are received, but imputing them to the period in which they were payable, through the corresponding complementary self-assessment, without penalty. No late payment interest or any surcharge.
The self-assessment will be submitted within the period between the date on which the arrears are received and the end of the immediately following period for submitting self-assessments by IRPF .
Thus, if the arrears are received between January 1, 2022 and the beginning of the deadline for submitting the personal income tax returns corresponding to the 2021 financial year, the complementary self-assessment must be submitted in said year before at the end of said submission period (until June 30, 2022), except in the case of arrears for the 2021 financial year, in which case they will be included in the self-assessment for said financial year. For arrears that are received after the beginning of the filing period for fiscal year 2021, the complementary self-assessment must be submitted within the period between the receipt of the arrears and the end of the filing period for fiscal year 2022, that is, the June 30, 2023.
See in this regard the regularization through presentation of complementary self-assessment in case of "Perception of arrears of work income" of Chapter 18.
In this regard, take into account article 67 LGT , which provides that the limitation period in case a) of article 66 (the right of the Administration to determine the tax debt through timely settlement) will begin to be counted “from the day following the day on which the regulatory period for submitting the corresponding declaration or self-assessment ends.” Therefore, the calculation of the limitation period does not begin until the end of the aforementioned period for submitting the complementary declaration.
Important : The complementary self-assessment must conform to the individual or joint taxation opted for in the original declaration.
C. Income derived from the transfer of the exploitation of copyrights
Regulations: Art. 7.3 Regulation Personal Income Tax
In the case of income derived from the transfer of the exploitation of copyrights that accrue over several years, the taxpayer may choose to allocate the advance payment to their account as the rights accrue.
Attention: If the taxpayer chooses to allocate the advance payment as the copyright accrues, he/she must check box  of the declaration.
D. Estimated work returns
Regulations: Art. 14.2 f) Law Personal Income Tax
The estimated income from the work must be attributed to the tax period in which the provision of the work or service that generates said income was carried out.
E. Benefits derived from pension plans
The work income derived from these benefits must be attributed to the tax period in which they are received, even if this does not correspond to that in which the contingency occurred.