By their own figures, SD Worx, Securex, Liantis and Acerta are the largest social secretariats in Belgium: each says it serves more than 70,000 employers or companies. Partena publishes 362,623 payslips a month. The official list of 20 June 2025 counts 25 recognised social secretariats with an active head office.
How many recognised social secretariats are there in Belgium?
The FPS Social Security has the list of recognised social secretariats published in the Belgian Official Gazette. The most recent list is dated 20 June 2025 and appeared on 15 July 2025. It counts 25 recognised secretariats with an active head office. The other names on the list have been struck off, are no longer active or have become a branch of another secretariat, often after a merger.
Under the royal decree of 28 November 1969, the Gazette must publish the full list every year in the fourth quarter. In practice it appears at varying times. You can also ask the NSSO Inspection Directorate for a copy.
Every recognised secretariat is a non-profit association (vzw/asbl) with a recognition from the Minister of Social Affairs. It groups at least 300 affiliated employers, or at least 100 employers who together employ at least 5,000 workers. Only a recognised secretariat may collect the NSSO contributions of its affiliated employers and pay them on. In 2025, 83% of employers were affiliated with such a secretariat. What that recognition means in law is explained in our guide which social secretariat to choose.
How to recognise a recognised secretariat. On its documents, invoices and publications it must state its name with the words "VZW - Sociaal Secretariaat" or "ASBL - Secrétariat social", its recognition number and the date of the ministerial decree granting the recognition. On a payslip you will usually find that number at the bottom.
The largest social secretariats in Belgium, ranked
The official list gives names and addresses, not numbers, and we found no government source that publishes the size of each secretariat. For the ranking we therefore use the number of employers each secretariat publishes on its own website. Those figures do not all count the same thing, so the last column shows exactly what is counted.
| Rank | Secretariat (recognition number) | Employers by its own figures | What is counted |
|---|---|---|---|
| 1 | SD Worx (640) | 92,000 | Belgian payroll clients |
| 2 | Securex (120) | 91,500 | employers of the whole group, active in 5 countries |
| 3 | Liantis (510) | 76,113 | employers who rely on the social secretariat |
| 4 | Acerta (250) | more than 70,000 | companies for which Acerta is the HR partner |
| 5 | UCM (200) | almost 25,000 | employers at the social secretariat |
| 6 | Group S (100) | 20,000 | employers of the HR provider Group S |
| unranked | Partena (300) | no number published | 362,623 payslips a month |
Payslips a month. Three secretariats publish how many payslips they calculate. Acerta says it makes more than 665,000 payroll calculations a month, Partena 362,623 payslips a month. Liantis says it carried out 5,149,383 payroll calculations in 2023, over the whole year. The pages we consulted for SD Worx, Securex, UCM and Group S give no number of payslips for Belgium.
Sources of the ranking, all consulted on 7 October 2026:
- SD Worx: sdworx.be, payroll and about SD Worx
- Securex: securex.be, about Securex
- Liantis: liantis.be, social secretariat and about Liantis
- Acerta: acerta.be, about Acerta
- UCM: ucm.be, les atouts du Secrétariat social UCM
- Group S: groups.be, discover Group S
- Partena: partena-professional.be, about us
The alternative: through a social bureau
Not every employer wants to join a large secretariat directly. Without an HR department, you can also go through a social bureau: a local office that does the work for you and works with a recognised secretariat. A social bureau is not in the ranking above, because it is not a social secretariat itself. It is a different model, alongside the secretariats.
| Directly with a social secretariat | Through a social bureau | |
|---|---|---|
| Who processes the payroll? | the secretariat, based on the hours you enter yourself in its portal or app | the bureau collects and processes your hours, the secretariat behind it files the returns |
| Who is your contact? | a case manager or contact person at the secretariat | one fixed person at the bureau who knows your file |
| Where? | an office of the secretariat | the bureau's office, close to you |
| What does it cost? | on quotation | on quotation |
One example is Business Centrum, a social bureau in Ghent and recognised partner of Acerta. Want Acerta without doing the work yourself? Go through us: Acerta remains your social secretariat, we are your fixed contact. With SD Worx, Securex, Liantis or Partena today? Then this is an alternative: you move to Acerta through a local bureau that arranges the switch for you. What a social bureau is, you can read in social bureau, and who does what in Acerta or Business Centrum.
Coming from one of the big names? Read an alternative to SD Worx, Securex, Liantis or Partena.
Is there a top 10 of social secretariats in Belgium?
An official top 10 of social secretariats does not exist. For seven secretariats we found a figure on their size on their own website. Below are the facts per secretariat, as they give them. What sets them apart in services, tools and pricing is covered in our guide Acerta, SD Worx, Securex, Liantis or Partena: the differences.
SD Worx (recognition number 640)
The recognised association is called SD Worx Sociaal Secretariaat and has its seat in Antwerp. In Belgium, SD Worx says it has more than 3,255 staff and 33 offices. It cites 92,000 Belgian clients who entrust their payroll to SD Worx. The group also works outside Belgium.
Securex (recognition number 120)
Securex is active in 5 countries. The group says 91,500 employers and 133,000 entrepreneurs rely on it, without a split by country. Besides the social secretariat, Securex has a social insurance fund for the self-employed, a business counter and a recognised external service for prevention and protection at work.
Liantis (recognition number 510)
Liantis has its seat in Bruges, more than 2,000 staff and 60 offices for all its services. The block "Liantis social secretariat in figures" shows 76,113 employers. The same page also says that the social secretariat advises and supports more than 44,000 employers every day. The group also has a social insurance fund, a business counter and an external prevention service.
Acerta (recognition number 250)
Acerta describes itself as an HR services group in Belgium, with more than 2,000 employees in 26 offices in Flanders, Brussels and Wallonia. According to the official list, the head office is in Leuven. Acerta says it makes more than 665,000 payroll calculations a month and is the HR partner of more than 70,000 companies. Acerta also has a social insurance fund and a business counter. Business Centrum works with Acerta.
UCM (recognition number 200)
The Secrétariat social UCM has its seat in Namur and says it groups almost 25,000 employers. UCM puts a price list online. What those prices cover is shown in our guide on the cost of a social secretariat.
Group S (recognition number 100)
Group S has its seat in Brussels. It calls itself the daily partner of 20,000 employers, with 700 staff in 20 offices. The group also has a social insurance fund and a business counter.
Partena (recognition number 300)
Partena Professional has its seat in Brussels, 1,747 staff and 29 offices in Belgium. For the social secretariat, Partena cites 362,623 payslips a month, but no number of employers. That is why Partena is unranked. Partena also has a social insurance fund and a business counter.
List of the other recognised social secretariats
The other eighteen recognised social secretariats on the list of 20 June 2025, with their head office as the list states it. The list says nothing about their size.
| Secretariat | Recognition number | Head office according to the list |
|---|---|---|
| Attentia | 110 | Brussels |
| Sociaal Secretariaat der Notarissen van België | 150 | Brussels |
| SST | 280 | Tournai |
| Le Cap | 370 | Chaineux |
| Sodalis | 540 | Sint-Michiels (Bruges) |
| Easypay | 600 | Leuven |
| Nationale Patroonsdienst | 650 | Merksem (Antwerp) |
| Orbiss | 710 | Antwerp |
| Sodibe | 750 | Antwerp |
| Sociaal Secretariaat voor Handel en Ambacht | 810 | Sint-Denijs-Westrem (Ghent) |
| Sodiwe | 850 | Mechelen |
| Accuria | 870 | Sint-Niklaas |
| Centrum voor Loonbeheer | 910 | Alken |
| SSE | 920 | Meulebeke |
| Salar | 950 | Kasterlee |
| Besox | 960 | Knokke-Heist |
| DPS | 980 | Aalst |
| Paycover | 995 | Brussels |
Three of these eighteen have their head office in East Flanders: the Sociaal Secretariaat voor Handel en Ambacht in Sint-Denijs-Westrem, Accuria in Sint-Niklaas and DPS in Aalst. A smaller secretariat has the same statutory tasks and the same supervision as a large one.
Is the largest social secretariat in Belgium also the best?
A best social secretariat does not exist in any measurable sense. Every recognised secretariat files the same statutory returns: Dimona, DmfA, the payment of contributions and payroll tax. Each is supervised by the NSSO inspection, which measures quality with a barometer covering 6 control areas. Each must lodge a guarantee. And with each of them, you as the employer remain liable for an error in a return.
Size tells you something about the number of specialists, in-house software and the office network. It tells you nothing about the person who handles your file every month. In practice, at every secretariat you work with one file manager or a small team. What matters for an SME with a handful of employees:
- does that person know your joint committee and the bonuses of your sector;
- do you call one fixed number, and who takes over during holidays;
- what do you pay per year for your actual staff, extras included.
The best social secretariat for you is therefore the one that gives the clearest answer to those three questions.
How do you choose a social secretariat?
- Check the recognition. Ask for the recognition number and look it up in the list above.
- Have your joint committee confirmed. The wrong JC means the wrong wages, and an inspection brings back pay with contributions.
- Ask who your fixed contact person is, with a direct number and e-mail address.
- Ask for a yearly price for your staff and your typical month, with the services charged separately. Our guide on the cost of a social secretariat shows how that bill is built up.
- Plan the switch. A mandate with the NSSO only moves at the start of a new quarter, and your current contract has a notice period. How that works is set out in changing social secretariat.
If you are hesitating between the big names, read Acerta, SD Worx, Securex, Liantis or Partena: the differences.
Rather make this choice with someone? Business Centrum puts your current contract next to a move to Acerta through us, and tells you when you can start and what you no longer have to do yourself.