We have been on the market since 2001. Our membership in both relevant professional associations TREUHAND SUISSE and EXPERTsuisse as well as the approvals by RAB together with the permanent training of our employees guarantees you high-quality services.

Digitalization has been a reality for us since 2001 and not just a buzzword. Our accounting data has been in the cloud since the beginning – before this term even existed. For more than ten years, our processes have been largely paperless, standardized and based on an extended quality assurance system. Our customers have access to extensive, constantly updated and improved samples and templates. This means the wheel does not have to be reinvented each time.

Thanks to the language skills of our employees and our membership in the international network of leading fiduciary companies of INPACT von we are the right partner for cross-border cases.

We strive for a long-term partnership with our customers, employees and the authorities. The WIESER Treuhand Group sees itself as a fair partner that values open and committed interaction.

Stefan Wieser
Stefan WieserOwner and CEO

Stefan Wieser has founded the group in 2001. Before that he worked amongst other positions at PwC in Switzerland and abroad. Stefan Wieser has a degree as business economist HWV, a diploma as swiss certified public accountant, is certified VAT specialist and licensed audit expert. Stefan Wieser himself has extensive experience in any kind of finance, tax and administration. He is board member, manager and director of about two dozen companies and an experienced entrepreneur. Stefan Wieser personally takes care of demanding annual financial statement, every audit- and challenging consulting mandate. In his leisure Stefan Wieser is a passionate sailor, who races against other boats, organizes blue water cruises and has crossed the Atlantic several times. With his motorcycle he explores the countries along the silk road. Further, Stefan Wieser is a member of the old boys network “Die Nothensteiner“.

Boba Kaiser
Boba KaiserSenior Manager

Direct +41 (71) 394 03 16

Boba Kaiser is a valuable pillar of our team since 2004 and became manager in 2010. She did her apprenticeship at a fidcuciary company and has ever since worked in this field. Boba Kaiser is specialized in annual financial statements, payroll accounting, human resource management and tax returns for individuals and corporations. Boba Kaiser is married and mother of a son and a daughter. In her leisure she likes to read and swim.

Renate Kohler
Renate KohlerManager

Direct +41 (71) 394 03 17

Renate Kohler has joined our team in 2014 and became manager 2018. After her apprenticeship in a fiduciary company she gained experience in an SME fiduciary company and in the two Big Four companies Ernst & Young AG and KPMG AG. Renate Kohler deals with accounting till the preparation of annual financial statements as well as human resources management. Further, she is specialized in value-added tax as well as taxes for individual persons and corporations. As she is an English native speaker, she provides support to a lot of your foreign-language clients. At the present time she is training while working for her Federal Diploma of Higher education (Certified Fiduciary). She compensates her work with sports and likes to travel.

Fidan Mustafa
Fidan MustafaMandate manager

Direct +41 (71) 394 03 15

Fidan Mustafa joined our team in 2018. He supports clients including annual financial statements and is also responsible for all the accounting of the companies of the WIESER Treuhand Group. In his free time, he actively plays football for KF Dardania St. Gallen.

Social commitment

We are engaged and characterized by persistence. We support among others since our foundation the aid organisation Coup de Pouce Vietnam. We know the volunteers of the association in Hanoi partly personally.


At the moment we have no vacancies.

At the moment we have no trainees.