Ennakkoperintärekisteri

The prepayment register is a Tax Administration register. If you are on it, a customer who pays you for work should not withhold income tax (ennakonpidätys) from the invoice. If you are not on it, many payers must withhold tax.

You apply on the YTJ founding notification or later in OmaVero. The Tax Administration can refuse or remove an entry if filings or tax payments are missing. Anyone can check the status on ytj.fi.

This is not the VAT register and not the employer register. You can be in one without being in the others.

Practical advice

Tick the register when you found the company if you will invoice other businesses.

After you convert a Toiminimi into an Oy, the new Y-tunnus needs its own entry.

If Vero warns that you may be removed, contact them at once and file the missing returns.

Where to seek advice

The best place to start is Finnish Tax Administration: https://www.vero.fi/yritykset-ja-yhteisot/verot-ja-maksut/ennakkoperintarekisteri/

Vero.fi explains how to join and what happens if you are not listed. Check a contractor on https://www.ytj.fi/ . For the founding form, Uusyrityskeskus can go through the ticks with you: https://uusyrityskeskus.fi/yrityksen-perustajalle/palvelumme-alkavalle-yrittajalle/

All the necessary links

vero.fi — Prepayment register rules.
ytj.fi — Public check of a business ID.
OmaVero — Apply or repair an entry.