It is the reference period for the contribution bases and rates when calculating the quota to be paid in terms of payment or compliance. Except when payments for longer or shorter periods are established or expressly authorised in the terms and conditions determined by the Ministry of Employment and Social Security, the payment periods will refer to full calendar months, although the earnings for them and/or their payment is made in periods other than months.
Payments for contributions corresponding to remuneration concepts included in the contribution base but accrued for periods of more than one month that are not periodical and are paid within the corresponding financial year will be distributed proportionally among the monthly payments for that year (e.g. extra payments). Similarly, if relevant, payments that cannot be fully or partially quantified in advance, for proportional distribution shall be settled.
The remuneration concepts received retroactively will be complementary payments, relating the contribution bases for each month separately, according to the bases, the types and other terms in force in the months to which the pay corresponds.
All quotas of the Social Security System and other concepts that are collected along with them shall be paid within the month following that corresponding to their earnings.