SGK and Bağ-Kur registration: what happens when you start work?

The question Zeynep the florist didn't ask

Zeynep opened a florist's shop. She had her mali müşavir (accountant) give the start-of-business notification (işe başlama bildirimi), and she got her tax certificate (vergi levhası) too. A month later, when she logged in to e-Devlet (e-Government), she saw it: a Bağ-Kur premium debt. Zeynep was surprised: "But I didn't register anywhere!"

In fact she had been registered. She didn't apply to Bağ-Kur separately; but her registration was opened automatically together with the start-of-business notification. In this lesson we look at the logic of this and the 2026 figures in plain terms.

What is Bağ-Kur?

Bağ-Kur is the old name of the social security insurance for people who work on their own behalf and account. Today its official name is subparagraph (b) of paragraph (1) of article 4 of Law No. 5510, that is, 4/b insurance. In short: someone who works for an employer is covered by SGK (Social Security Institution) as 4/a, and someone who runs their own business is 4/b.

Owners of sole proprietorships, partners in limited companies and some tradesmen registered in the tradesmen's registry (esnaf sicili) fall within this scope. In this lesson we focus on the owner of a sole proprietorship.

Automatic registration: you don't apply

Under Law No. 5510, the insurance of a 4/b insured person who is an income taxpayer starts on the date their tax liability starts. The insurance is tied to the tax liability record at GİB (Revenue Administration); SGK registers you by looking at these records.

So this chain works:

1. You give the start-of-business notification.
2. The tax office opens your tax liability.
3. This record is passed to SGK.
4. Your Bağ-Kur insurance starts from that date.

That is why there is no separate "let me go to Bağ-Kur" step. But you can check that your insurance has started from the information that comes from SGK, or on e-Devlet. If you also work as an insured employee somewhere else, or if you are retired, the situation may be different; be sure to ask your mali müşavir or SGK about this.

Back to Zeynep: her tax liability started on 1 March, and her Bağ-Kur started on 1 March too. Making her first sale late in the shop didn't change this insurance.

How much is the premium? (for 2026)

The premium is calculated on an amount called earnings subject to premium (prime esas kazanç). This is not the shop's real profit; it is the monthly amount you choose for calculating the premium. This amount has a lower and an upper limit. Many tradesmen pay from the lower limit; and if you don't make a choice, the premium is calculated from the lower limit. The figures for 2026 are as follows (according to the SGK circular and secondary sources):

The minimum premium works out like this: 33,030 × 35.75% = 11,808.23 lira. For Zeynep, who declares her earnings at the lower limit, this is her monthly premium.

The five-point reduction

If you meet the conditions, the state applies a reduction that lowers the premium rate by 5 points. The reduced rate is 30.75%, and the minimum monthly premium becomes 10,156.73 lira (33,030 × 30.75%).

According to secondary sources, the conditions for the reduction are:

• Being a compulsory 4/b insured person
• Paying the premium on time
• Having no debt to SGK for premiums, administrative fines or late payment charges

In a month you don't pay on time, the reduction is lost. Voluntarily insured people cannot benefit from this reduction. Have your mali müşavir or SGK confirm whether the reduction applies in your case.

These figures are for 2026. They are set again every year; if you are reading this later, check the current figure.

When is it paid?

The premium is paid by the last day of the month following the month it relates to. The March premium is due by the last day of April. If you pay late, a late payment charge (gecikme zammı) runs and you can't benefit from the reduction. If your debt builds up and goes past 60 days, problems may also arise when you get health care at a hospital (there are exceptions, such as emergencies).

So you don't forget to pay

• Write "Bağ-Kur" in your calendar for the last week of the month.
• Even if you will pay the premium from your personal account rather than the business account, add the amount to your monthly budget. If separate accounts are the topic, see the lesson Cash, bank and the money in your pocket: three separate pockets.
• The Bağ-Kur premium is an obligation separate from tax. If you are under real taxation (gerçek usul) (if you keep a business book or balance sheet books), the premium you pay can be recorded as an expense; remind your mali müşavir about this. If you are under simplified taxation (basit usul), ask your mali müşavir how this affects you. Which spending can be recorded as an expense is in the article Which spending can be recorded as an expense? (in Turkish).

Is it really this fixed?

Whether Zeynep has a profitable month or a weak one, the premium stays the same, because the premium is calculated not on what she earned that month but on the earnings subject to premium she chose. Even in a month she doesn't open the shop at all, the premium runs if her registration is still open. If you want to stop your business, just closing the shop is not enough; you need to give the tax office a cessation of business notification (işi bırakma bildirimi). Bağ-Kur ends when your tax liability ends.

Being covered by Bağ-Kur also gives you a pension and health cover. The premium may look like a burden, but it is money you put into your own future. Talk with your mali müşavir about how the figures apply to your own situation: What a mali müşavir does and does not do

Summary

• With the start-of-business notification, your Bağ-Kur registration starts automatically.
• For 2026 the rate is 35.75% and the minimum monthly premium is 11,808.23 lira; for those who meet the conditions, 10,156.73 lira with the 5-point reduction.
• The premium is paid by the last day of the month following the month it relates to.
• Have your mali müşavir confirm the figures.