We are one team!

We don’t hesitate we act!

When you have a dream –
stay on course & chase it!



Acting instead of reacting

Being one of the leading and most innovative boutique tax consultancies in Liechtenstein, we offer consultancy services relating to the DACHLI region (Germany, Austria, Switzerland, and Liechtenstein). Moreover, we are devoted to new technologies and are continuously evolving in order to detect and master new challenges.

#challenge today & change tomorrow

Our clients appreciate this vision and expertise as well as our reliability, the individual support and advice we provide. Due to our affinity for new technologies, many companies active in the fields of blockchain and FinTech place their trust in us.

#see the whole picture & build long-term partnerships

“We provide the maximum of freedom to allow to focus on the important aspects of life.”

Matthias Langer, Partner

Matthias Langer, Partner

Partner & Team

Matthias Langer

Matthias Langer

Father and entrepreneur

I am not only an expert in the tax laws of Liechtenstein and Germany as well as in cross-border transactions and consultancy in the fields of cryptocurrency and blockchain, I also have a good insight into human nature and an understanding of the bigger picture. This way, I enable our clients to enjoy their lives without having to worry about taxation. Furthermore I help my colleagues to improve and evolve every day.

Languages: German, English, and Latin

Partner and Tax Consultant

Tanja Monz-Lettenbichler

Tanja Monz-Lettenbichler

Photographer and amateur chef

I am open to new things and very flexible. In the context of my expertise in Austrian tax law and accounting I quickly adapt to new circumstances and find new solutions, which is reflected, among other things, in my work as a tax consultant.

Languages: German, English, Spanish, and Italian

Partner and Tax Consultant

Sabine Sieber

Sabine Sieber

Action fan and family person

Based on my expertise in financial statements and VAT issues as well as my passion to optimise processes and present solutions, we manage the automated booking of receipts, create accounting practices for blockchain and FinTech, and clarify accounting issues regarding Liechtenstein. My ability to recognise the strengths of our employees and specifically deploy them within the team and for the benefit of our clients, spurs our development.

Languages: German, English, and French

Partner and Legal Advisor

Sascha Valenta

Sascha Valenta

Band member and self-appointed happiness officer

I build trust quickly and have a good insight into human nature. In addition to my activities in the field of trusts I therefore want to create a professional environment in which everybody loves to work and is happy. This also includes supporting our team in all matters at all times.

Languages: German, English, French, and Japanese

CEO, Partner, and Trustee

Show team

“At actus ag we are open minded and continuously tackle new challenges. This is especially true for the fields of IT, marketing, and process optimisation.

In addition to our daily business, we embrace new technologies, want to advance our consultancy forward and thus continuously provide added value to our clients.”

Sabine Sieber, Partner

Sabine Sieber, Partner

This is us #actwithus

actus ag –
from 2016 to 2021


  • Collaborating with Andersen Global in Liechtenstein.


  • More than 700 clients in 25 countries
  • More than 50% of clients from FinTech companies & cryptocurrency exchanges
  • Number of employees doubled: 19 members of staff – more than 400 m² of office space


  • Interfaces for cryptocurrency exchanges & banks
  • Automated booking of cryptocurrency transactions
  • 8 members of staff and a rising number of blockchain & FinTech clients
  • Members of the IFA Liechtenstein executive board
  • First publication on Liechtenstein tax law including the taxation of blockchain & FinTech companies


  • First STO client in the European Economic Area


  • First cryptocurrency client in Liechtenstein
  • Team grows to 6 members of staff


  • September 2016: founding of actus ag
  • 4 partners in a 40 m² office

Partners, Clients & Memberships

Our Community

“At actus ag we are acting together, inspiring each other and giving each other support. Because our passion unites us!”

Sascha Valenta, Partner

Sascha Valenta, Partner