When you’re self-employed in Belgium, you’re legally required to register with a social insurance fund, also called a social security fund. But how do you choose a fund? Below, we compare the services offered by the different social insurance funds in Belgium to help you make your decision.
In Belgium, social insurance funds, or social security funds, are responsible for calculating and collecting social security contributions from the self-employed. These contributions are then forwarded to the State by the social insurance fund.
In return for the contributions you pay quarterly when you’re self-employed, you receive social protection, which includes things like your statutory pension, family allowances, or benefits in the event of illness.
This is the basic function of a social insurance fund, but many also offer additional services. Of course, your social insurance fund also serves as your point of contact for all your questions about being self-employed, social security contributions, and your self-employed status.
You can freely choose which social insurance fund to register with. But before making a decision, we recommend that you carefully examine the services each provider offers.
Some offer more personalised support than others or have specialised services that might be more suited to your company's needs.
To avail of the services offered by your social insurance fund, you pay an administration fee. This is a percentage of your social security contributions, and it varies between 3% and 4.45%, depending on the fund.
Below, you can find an overview of the nine recognised social insurance funds, or social security funds, in Belgium (in alphabetical order).
Acerta describes itself as a HR services group that supports entrepreneurs at every stage.
Additional services beyond the basics:
Acerta is popular with growing Small and Medium-Sized Enterprises (SMEs) that want personalised support. With over 25 offices and an online platform, this social insurance fund is very accessible.
Admin fees: 3.05%
Avixi is a less well-known and smaller social insurance fund that offers basic social security services. The range of services offered is therefore narrower than that of larger funds.
Additional services beyond the basics:
With Avixi, you can manage your business admin online, but you have fewer tools and technological resources than in large social security funds. On the other hand, you benefit from an approach that is very personal, human, and easy to understand.
This social insurance fund has four offices: one in Brussels and three in Flanders.
Admin fees: 4%
The National Fund is a special case: it’s a public social insurance fund that’s part of the National Institute for Social Insurance of the Self-Employed (NISSE, or INASTI/RSVZ in French/Dutch). Although it’s an autonomous entity in an administrative sense, it’s not a distinct legal entity.
Additional services beyond the basics:
This social insurance fund is the fund that self-employed entrepreneurs are automatically registered with if they don’t choose a social insurance fund themselves.
The National Fund has around ten offices in Brussels, Wallonia and Flanders. Digital support is limited. If you register with the National Fund, you’ll need to handle a larger portion of your administrative tasks yourself.
Admin fees: 4.25%
The Brussels-based social insurance fund Group S specialises in HR support for freelancers, starters and employers.
Additional services beyond the basics:
As a HR service provider, Group S offers advanced digital services, with practical and efficient self-service tools. At the same time, Group S offers a personalised service.
With only one office, located in Brussels, this social insurance fund is most accessible to entrepreneurs in the Brussels-Capital Region and surrounding areas. Of course, you can always ask your questions to Group S online.
Admin fees: 3.90%
Liantis is a large social insurance fund offering a wide range of services that go well beyond social security.
Additional services beyond the basics:
Liantis caters to all kinds of self-employment, from being self-employed in a secondary occupation to SMEs, across diverse sectors. It's a good choice if you're looking for an all-in-one partner capable of supporting your business on multiple levels.
The company is very accessible, both online and in one of the 35+ physical offices across Belgium.
Admin fees: 3.95%
With its social insurance fund, Partena Professional places an emphasis on flexible support and a personalised approach. It primarily targets small businesses, startups, and freelancers, positioning itself as a one-stop shop for entrepreneurs seeking a fund that can collaborate with them and support their growth.
Additional services beyond the basics:
Partena Professional’s online platform gives you access to a wealth of documents and information to easily manage your admin. You can also visit them in person, as Partena has dozens of offices in Brussels, Wallonia and Flanders.
Admin fees: 4.25%
The social insurance fund of Securex caters to the self-employed, freelancers, and entrepreneurs across various sectors. However, given Securex's extensive HR services, it's fair to say they primarily focus on self-employed entrepreneurs who employ staff.
Additional services beyond the basics:
In addition to a self-service platform, Securex has more than 30 offices in Brussels, Wallonia and Flanders.
Admin fees: 4.10%
UCM is a French-language social insurance fund, active in Brussels and Wallonia.
Additional services beyond the basics:
This social insurance fund is renowned for its flexible and customer-oriented approach, adapted to the development phase of your business.
There are more than 20 local UCM offices across Brussels and Wallonia. And with an online account, you can also manage your business admin, training, and other products yourself.
Admin fees: 4.05%
As a social insurance fund, Xerius caters to both starters and experienced self-employed entrepreneurs. It’s renowned for its high-performance and user-friendly digital platform, which is packed with information, documents, and helpful tips to assist you with your business admin. An ideal solution for entrepreneurs who prefer to manage their admin online.
Additional services beyond the basics:
If you’re looking for face-to-face support, you can easily make an appointment with a Xerius advisor, whether online or in one of their offices: there are around ten offices, across Belgium’s regions.
Admin fees: 3.05%
| Fund | Fees as % |
| Acerta | 3.05% |
| Avixi | 4% |
| National Fund | 4.25% |
| Group S | 3.90% |
| Liantis | 3.95% |
| Partena Professional | 4.25% |
| Securex | 4.10% |
| UCM | 4.05% |
| Xerius | 3.05% |
Admin fees in 2025
Are you dissatisfied with the services provided by your current social insurance fund? If so, you can request to change funds and register with a different fund.
However, there are certain conditions that must be met if you want to change social insurance fund.
It’s therefore in your best interest to gather as much information as possible before deciding which social insurance fund to register with in the first place.
Accountable automatically calculates your social security contributions based on your income. And every quarter, we remind you when it's time to pay them.
Author - Valesca Wilms
As content marketing lead at Accountable Belgium, Valesca writes about freelancing, self-employment, and taxes based on her own experience as a freelancer.
Who is Valesca ?Thank you for your feedback!
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