We are a market-leading, Switzerland-wide acting, internationally known and regionally anchored consulting firm for finance and accounting, as well as tax, auditing and HR services. Customers enter into long-term relationships with us because we steadily provide quality work and have many years of broad-based industry knowledge. 


Each enterprise has a comprehensive consulting partner so that it can achieve more long-term success.


  • Quality and Competency
We commit to high quality and ensure this through in-depth expertise and professional knowledge, years of experience, and continuing education. With these qualities, we aim for efficient processes and long-term, partnership-based customer relationships.
  • Partnership-based
We are dynamic and cooperative in dealing with customers, partners and the team.
  • Added value for our customers
Our passion for comprehensive advice and innovative solutions always adds value to our customers. We consciously go the extra mile for them.
  • Confidence-building communication
We maintain open, respectful, trusting and integrity-based communication with our employees, customers and partners.


  • Thanks to our extensive know-how, you benefit from more mature total solutions, regardless of the size or the situation of your company.
  • Thanks to nationwide coverage and a partner network, you profit from simpler and more optimal processes for national and international business.
  • Thanks to the knowledge of our experts, you profit from faster solutions.
  • Thanks to a high degree of innovation, you benefit from a high degree of adaptability to changing markets and needs.
  • a&o kreston audit ag, Baar (Canton Zug), was founded in 2010 as a spin-off of another trustee corporation. a&o kreston audit ag was held and managed by Dr. oec. Manuel Vogel, a well-known expert in international taxation and value-added taxation.
  • Ortag, Organisations-, Revisions- und Treuhand AG, Zurich, was founded in 1946. The organization was held and managed for many years by Roger Werner, primarily active in the areas of organizational consulting and accounting, as well as by Alfred Fehlmann, specialized in the areas of audits and taxes.
  • Esther Holm GmbH, Horgen (Canton Zurich), was founded in 1996 and since then has been built and managed by Mrs. Esther Holm.
  • artel treuhand ag, Zurich (Canton Zurich), was founded in 1991 and has been successfully focused on supporting smaller companies and start-ups, which are supported by an innovative portfolio of services and methods. Mr. Bora Erbil has built and managed that company since then.

Our Partners