I've received the contribution adjustment letter: what do I do now
If you’re an autónomo (self-employed worker) and you’ve received a letter from the Tesorería General de la Seguridad Social (the Spanish Social Security treasury) with an amount you weren’t expecting, take a breath. You’re not alone and it’s not a fine. It’s the contribution adjustment (regularización de cuotas), a new process that affects all self-employed workers since the system of contribution by real income came into force.
This guide explains what that letter means, how the difference they’re claiming from you (or that they owe you) is calculated, and above all how to stop it catching you off guard again next year.