Hans Wadsack founded the sole proprietorship "Hans Wadsack, Treuhand- und Steuerberatungsbüro" in the city of Zug on 1st July 1983.

At the beginning of 1989, the sole proprietorship is converted into a limited partnership, namely wadsack & co. treuhandgesellschaft.

2002 Acquisition of Schlumpf & Partner Treuhand AG, Zug.

2010 Acquisition of WEY & SPIESS Treuhand und Revisions AG, Zug.

With the acquisition of Revo Treuhand AG and the relocation of the company's registered office to the city of Solothurn in November 2015, business activities are being expanded to the canton of Solothurn.

From 2015 to 2018 Lukas Wadsack, Mark Rüfenacht and Cyril Heer enter the partnership as successors of Hans Wadsack.

In May 2018, the limited partnership is then transformed into the current form of a joint stock corporation. As part of this restructuring, the former subsidiaries Schlumpf & Partner Treuhand AG, WEY & SPIESS Treuhand und Revisions AG and Revo Treuhand AG are renamed.

Since May 2018 we are operating as WADSACK.

In January 2019, WADSACK opens another branch in the city of Grenchen in the canton of Solothurn.



We offer our customers a high quality of service. This requires the targeted support of our colleagues and the willingness to constantly develop professionally and personally. Our employees have the highest training diplomas available in Switzerland.

Tradition and modernity

We cultivate traditional values and have a modern approach. The future brings us many opportunities, which we are tackling together. We are ideally positioned to master the challenges. We want to maintain intensive personal contact with our customers despite the most modern working tools.


Work should not only be obligatory, but also meaningful. We want to challenge and encourage our employees in their professional and personal development and provide ways to allow room for hobbies and family in addition to demanding everyday work.

Personality and respect

We treat each other with respect and attach great importance to a positive working atmosphere. At our internal professional and social events, we cultivate personal exchange.

Local anchoring

We want to share our success with our environment. We promote local sports clubs and support social events such as the Zug Fencing Club, FC Solothurn, and as co-sponsor FC Grenchen and Bob Team Friedli. We also support various social and cultural events in the region of Zug and Solothurn, such as the Solothurn Film Festival.