“ADC Group is an excellent fit with PIA Group," says Steven Brouckaert, PIA Group’s Executive Chairman. "The firm combines deep local roots with a distinct advisory culture and a long-term vision. These are exactly the entrepreneurial firms with which we want to build the future of our sector. We don’t take over their identity. On the contrary, we provide them with the resources to consolidate and further develop it.”
A strong partner in the border region between Belgium and Luxembourg.
ADC Group traces its origins back to 1990, when Werner Müsch established an accountancy firm in Recht, in the East Cantons of Belgium. Owing to its location in the border region, the firm soon attracted many entrepreneurs with business activities in both Belgium and Luxembourg. A few years later, this led to the establishment of AD Consult, located just outside Luxembourg City.
Building on this deep Belgian-Luxembourg anchoring, ADC Group has grown into a well-established firm with four offices today, in Sankt Vith, Verviers, Weiswampach and Steinfort. The firm currently employs 31 people and its 6 partners, Werner Müsch, Dirk Heinen, Micha Nilles, Raphael Ruess, Dylan Brülls and Corinne Breuer, will become shareholders of PIA Group. Its clients are primarily family-owned SMEs that rely on the firm for bespoke support in accountancy, taxation and business advisory services.
A deliberate choice for the future
“We have never viewed growth as an objective in itself, but rather as a way of ensuring that we can continue to offer our clients the quality they expect from us," says Werner Müsch. “Nowadays, our profession is changing faster than ever before. Peppol is just one example of the automation that is transforming our sector. Artificial intelligence will also fundamentally change the way accountants work. Making the right decisions in this environment requires both specialist expertise and the capacity to invest. For our younger partners, joining PIA Group is therefore a deliberate choice for the future."
Locally where it creates value, together where it makes us stronger
According to Nathalie Calle, CEO of PIA Group Belux, ADC Group fits seamlessly with the group's philosophy. "Our starting point is simple: locally where it creates value, together where it makes us stronger," she explains. "The identity of the firm, the entrepreneurial spirit of its partners and the relationship with their clients are always the starting point. At the same time, we strengthen our firms with specialised support in the areas of IT, HR and digitalisation. Together, we continuously look for more efficient processes and smart standardisations that prepare our offices for the future, without losing their own identity."
Technology that empowers people
For Steven Brouckaert, technology is an essential building block of that future.
"The technological evolution offers boundless opportunities for our sector. That is why, as a group, we are making targeted investments in artificial intelligence, data and digital platforms that automate repetitive tasks and make knowledge available more quickly. This creates more time for our accountants and experts to focus on what entrepreneurs truly need today: personal discussions, strategic advice and guidance with complex decisions. Within PIA Group, technology strengthens the human relationship with the client."
This vision closely aligns with the approach ADC Group has been implementing for many years.
"For many SMEs, accounting is a necessary evil," says Werner Müsch. "Every single day, we prove the opposite. Through structure, respect for deadlines and proactive advice, we turn figures into a tool for better entrepreneurship. Thanks to PIA Group, that role will only go from strength to strength."
Continuity for clients, fresh opportunities for employees
Our clients won’t notice a thing in our day-to-day collaboration. They will continue to work with the same trusted contacts and can rely on the same personal service. Behind the scenes, however, ADC Group will be able to tap into an extensive network of expertise.
Clients will also gain access to PIA Group's specialised advisory services, including legal, VAT, corporate finance, wealth planning and digital transformation. The affiliation also offers new perspectives for employees through knowledge sharing, career development opportunities and collaboration with colleagues from Belgium, Luxembourg, the Netherlands and Germany.
"Our clients choose people who know their business and think along with them," concludes Werner Müsch. “Nothing will change in that regard. The only difference is that we now have access to even more expertise to support them when their challenges become more complex."
Part of an expanding international group
With the affiliation of ADC Group, PIA Group continues its sustained growth trajectory. Following the addition of five firms earlier this year, the group is once again expanding its ranks in Belgium and Luxembourg.
"2026 got off to an excellent start but our ambition goes further," concludes Steven Brouckaert. "More and more enterprising firms are looking for a partner that respects their identity while also providing the scale to invest in people, technology and innovation. It is this combination that makes PIA Group unique. We will therefore continue to actively build our position, not only in Belgium and Luxembourg, but also in the Netherlands and Germany."
About PIA Group
In a market based on economies of scale, PIA Group aims to be a leading international provider of accountancy, audit and advisory services whilst retaining a personal connection between its staff and clients. We therefore drive our growth forward with a continuously expanding group of enterprising partners. The mutual interaction between those partners and our expert teams enables each PIA office to offer entrepreneurs tailored up-to-date services and expertise that genuinely contribute to their professional success and personal happiness. PIA Group was founded in Belgium in 1999 by Steven Brouckaert. The group operates in Belgium, the Netherlands, Luxembourg and Germany, with a total of more than 160 branches and 3,750 staff across these four countries. Over 2025, PIA Group’s Benelux offices realised a turnover of €440 million.
www.pia.be
www.pia.lu
www.adc-group.net
