This notification from Seguridad Social (Spanish Social Security) may be related to one of the following:
- It is an additional payment due to a recalculation of the autónomo’s income.
You can view the details in your personal Social Security account through the IMPORTASS portal:


If your autónomo was registered in the second half of last month, this is a proportional contribution for that previous month, which will be charged at the end of the current month.
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