Who are we?

Two personalities,

two perspectives –

one complete solution

Olivia Grossen and Mathieu Jaus have been working together for 10 years. They love taking on challenges and developing tailor-made, straightforward and promising solutions for their clients. They value communication as equals, recognizing that not everyone is familiar with technical business and financial terminology.

“We work with passion - our clients’ success is our success. Fairness is at the heart of everything we do.”

More about us

Mathieu Jaus

M.H. HSG & Swiss Certified Public Accountant

For over 20 years, Mathieu Jaus has successfully run Copartner Revision AG as its owner (and, up until two years ago, as managing director). But his passion extends far beyond this company. He enthusiastically dedicates himself to his other projects, such as Bächtiger Liwoba Immobilien AG and Mayer & Bosshardt AG. Even though these companies are outside his area of expertise, he finds it exciting to take on new challenges and actively drive these businesses forward and develop them further.

His passion for the world of SME is evident in his numerous involvements on boards of directors, foundation boards and executive boards. Wherever financial expertise is needed, he is there – and successfully.

Beyond his professional activities, Mathieu Jaus is actively involved in academia as President of the HSG Alumni Association in St. Gallen.

Furthermore, he shares his knowledge with the community by serving on boards and foundations in the Northwest Switzerland region on a reduced-fee or pro bono basis (including, but not limited to, Stiftung Basel ist Sport, Demenz Meet, FiKo Schweizerischer Fussballverband, and Sportbeirat BS).

Olivia Grossen

Advanced Federal Diploma of Higher Education in Business Administration

With 10 years of banking experience and another 10 years in business administration, focusing on fiduciary services and corporate management, Olivia Grossen offers a broad range of expertise.

During her time at Copartner Revision AG, she successfully led numerous projects, was responsible for the finances of SME, served as Head of HR, and managed her own client base.

Alongside her professional achievements, she actively influenced the company culture as a member of the executive management team and played a key role in the organization’s growth.

In 2024, she decided to build her own company and launch ariina circular ag.

Selected Experiences:

Traditional fiduciary services for SME in the region
Recruitment of over 50 employees in the last 10 years
Setting up the charity gala of the foundation «Basel is Sport»
Management of the foundation «Basler Zeitung hilft Not lindern»
Management of PCE Suisse GmbH, the Swiss branch of PCE Holding in Hamburg
Representative of the Board of Directors of Bächtiger Liwoba Immobilien AG

“Every encounter is like a blank sheet of paper, on which a shared story is yet to be written”