Norbert
Blume
Consultant
Telephone: +49 (0)441 9710-0
Focus of activities:
- Supporting strategic business development through digital transformation
- Evaluating requirements and supporting implementation in digitalisation and artificial intelligence, taking a holistic view of the current state and future opportunities
About me
After studying Business Administration and Economics at the University of Bremen, I have supported major transformation and IT projects – from strategic assessments and due diligence processes to the development and negotiation of the associated contracts. This combination of business, legal and technological perspectives shapes my approach to consulting: I deliberately consider requirements in their broader context rather than from a purely technical perspective.
As a certified AI Manager, I support organisations with AI roadmaps, governance, risk assessment and compliance, including requirements arising from the EU AI Act.
I advise organisations on make-or-buy and sourcing decisions, provider and contract models, and the selection of suitable infrastructure to ensure that AI can be deployed in a reliable and fit-for-purpose manner.
Together with our partners, we cover the entire journey – from initial requirements analysis and implementation through to the long-term delivery of IT and AI services. My role is to bridge the gap between management, business units, legal teams and technology, helping initiatives move from concept into successful day-to-day operations (Concept ➔ Implementation ➔ Services).
https://treuhand.de/app/uploads/2026/08/blume_norbert.jpg 800 800 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2026-08-10 14:46:272026-08-10 14:53:01Norbert Blume
Anna-Tabea
Lettmann
Auditor, Tax Adviser
Telephone: +49 (0)441 9710-0
Focus of activities:
- Preparation and review of annual financial statements and consolidated financial statements
- Preparation of tax returns for businesses and individuals
- Tax and business advisory services
https://treuhand.de/app/uploads/2024/06/Anna-Tabea-Lettmann_team.jpg 1200 1200 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2026-06-15 10:49:432026-06-15 10:57:27Anna-Tabea Lettmann
Luigi
Argentato
Consultant
Telephone: +49 (0)441 9710-0
Focus of activities:
- Business Development & Strategic Growth
- AI, Cybersecurity & Digital Transformation
- Partnerships & Market Expansion
About me
With more than 20 years of experience in sales, technology and executive leadership, I help organizations leverage innovation to drive sustainable growth. My expertise spans artificial intelligence, cybersecurity, digital transformation and business development.
I focus on translating complex technologies into practical business solutions that deliver measurable results.
Luigi Argentato is Managing Director at Treuhand Digital Services GmbH.
https://treuhand.de/app/uploads/2026/06/argentato_luigi-treuhand-digital-services.jpg 800 800 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2026-06-08 09:15:582026-07-17 11:34:49Luigi Argentato
Philipp
Krieg
IT-Consultant
Telephone: +49 (0)441 9710-254
Focus of activities:
- IT auditing (IT auditing, IT certification, IT security)
- IT project management
- IT planning, design, IT organization, and product and service provider selection
Über mich
I have over 20 years of experience in management positions at an IT systems company in the automotive sector, where I worked as an team leader, deputy department head, and project manager. My focus has always been on providing the best possible service to our customers.
As part of Treuhand management consultancy, I specialize in IT consulting and IT auditing as part of annual audits.
My core competencies include IT strategy, IT operations, and IT security, particularly for medium-sized companies. With my many years of expertise, I help to make our customers’ IT landscapes efficient, secure, and future-oriented.
https://treuhand.de/app/uploads/2025/08/philipp-krieg-it-beratung.jpg 800 800 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2026-01-16 13:15:322026-03-03 10:36:28Philipp Krieg
Marcus
Ahrens
Lawyer
Telefon: 0441 9710-200
Focus of activities:
- Mergers & Acquisitions
- Corporate Law
- Contract Drafting, in particular with regard to tax law aspects
- Tax Law
- Business Law / Commercial Law
- Litigation
About me
My aim is to provide advice that is not only legally excellent but also economically sound.
A native of Delmenhorst with family ties to Bremen and Oldenburg, I returned to my home region of Weser-Ems after studying law in Göttingen to complete my legal clerkship – and I have remained closely connected to the area ever since. I have been a fully qualified lawyer since June 2008. I first practiced as an attorney within a medium-sized group of companies comprising auditors, tax advisors, and lawyers. From 2014 to 2021, I served as partner and managing director in this group.
In addition, I held a senior role in the public sector with both managerial and wide-ranging legal responsibilities.
I look forward to tackling challenging tasks and complex issues, and to providing comprehensive legal advice in this context.
https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg 0 0 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2025-10-27 11:43:352025-10-27 11:43:35Marcus Ahrens
Jan-Niklas
Panjer
Lawyer
Telephone: +49 (0)441 9710-200
Focus of activities:
- Corporate law and tax advice for companies
- Mergers & acquisitions
- Corporate succession
About me
Coming from the Emsland region, the Weser-Ems region is particularly close to my heart. After graduating from a business-oriented grammar school in Papenburg, I moved to Osnabrück to study law. It was clear to me early on that I wanted to provide legal advice to medium-sized companies after my studies so that I could use my knowledge and skills to help our region remain a growth region. In line with this vision, I focused my studies on corporate and capital market law. For several years, I was an honorary member of the board of the Osnabrück Legal Tech Forum, which I founded with interested fellow students and with which we jointly organized events in the field of legal tech and digitalization in law at the university.
After my first state examination in 2022, I began my legal clerkship in the same year with various stations in Emsland, Osnabrück and Oldenburg before successfully passing my second state examination in December 2024.
After my admission to the bar, I am now ready to fulfill my vision of strengthening companies from our region. At Treuhand, I will be primarily responsible for advising companies on corporate law and tax matters.
https://treuhand.de/app/uploads/2025/02/panjer-jan-niklas-team-rechtsberatung.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2025-02-11 10:23:462025-03-24 08:11:16Jan-Niklas Panjer
Claudia
Averbeck
Tax Adviser*, Certified Adviser in International Taxation
*Certified Advisor in Business Succession (DStV e.V.)
Telephone:+49 (0)441 9710-0
Focus of activities:
- Advice on Taxation, Tax Structuring, especially for cross-border transactions
- Transfer Pricing, including Structuring and Documentation
- Taxation of Permanent Establishments domestic and abroad
- Advice on International Deployment of Employees
- Advice on National and International Tax Audits
- Preparation of Tax Returns and Annual Financial Statements
About me
In a globalized world, sound tax advice is a decisive success factor. My focus is on providing tax advice to medium-sized companies, their shareholders and private individuals, especially in cross-border transactions. This includes, in particular, the areas of transfer pricing and its documentation, the taxation of permanent establishments in Switzerland and abroad and the international deployment of employees.
The Treuhand’s membership of the HLB International network is also of great importance, as it facilitates professional exchange with colleagues from all over the world. It is particularly important to me to explain even complex considerations in an understandable way and to develop sustainable solutions. This makes tax advice not only effective, but understandable! And when I’m not dealing with laws and taxes, I like to spend time with my family and friends.
Claudia Averbeck is partner at Treuhand Weser-Ems Wirtschaftsprüfungsgesellschaft.
https://treuhand.de/app/uploads/2023/12/Averbeck.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-17 11:28:392026-01-09 09:49:33Claudia Averbeck
Jonas
Dettmers
Auditor, Tax Adviser, Sustainability AuditorIDW
Telephone: +49 (0)441 9710-0
Focus of activities:
- Auditing and preparation of annual and consolidated financial statements
- Tax and business consulting
- Company valuations
- Due diligence reviews
- Special audits in the energy sector in accordance with the Renewable Energy Sources Act (EEG), the Combined Heat and Power Act (KWKG), and the Capital Investment Act (KAV)
About me
I laid the foundation for my professional career by studying economics at the University of Oldenburg.
I gained my first practical experience in the field of auditing during two internships in 2015 and 2016 at a Big Four company and at Treuhand Weser-Ems GmbH, where I have remained ever since.
After starting my career at Treuhand Weser-Ems GmbH in 2017, I successfully passed the tax advisor exam in 2020 and the auditor exam in 2023.
In addition to the traditional auditing and preparation of annual and consolidated financial statements, I have specialized in company valuations and due diligence audits since the beginning of my professional career.
My work as a certified public accountant and tax advisor offers more than just statutory audits. Our often family-run medium-sized companies expect proactive and approachable strategic advice, rather than just checking numbers. With this in mind, I also stand for pragmatic and goal-oriented solutions.
Jonas Dettmers is partner at Treuhand Weser-Ems Wirtschaftsprüfungsgesellschaft.
https://treuhand.de/app/uploads/2024/01/jonas-dettmers-team-1.jpg 2208 2208 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-05-23 11:54:542026-01-09 11:21:13Jonas Dettmers
Verena
Dietermann
Lawyer
Telephone: +49 (0)441 9710-200
Focus of activities:
- Employment law advice and structuring of legal relationships
- Collective and individual employment law
- Works constitution law
- Transfer of undertakings and restructuring
- Managing director employment relationships
- Drafting civil law contracts
- Litigation representation
About me
I advise employers and entrepreneurs from a wide range of industries with a focus on purpose-oriented and cost-effective solutions. I attach great importance to transparent, trusting cooperation and good communication. My aim is to deal with any legal issues that arise for my clients quickly and efficiently and to support them in implementing their interests.
After completing my studies in Frankfurt am Main, I have been working as a lawyer since 2014. I advise and represent clients on employment law and civil law issues in a national and international context.
I enjoy developing individual, situation-specific strategies and will be happy to support you in implementing your plans. Please feel free to contact me directly.
https://treuhand.de/app/uploads/2024/01/team_dietermann.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-17 12:25:512025-03-10 11:40:01Verena Dietermann
Sarah
Faßhauer
Consultant
Telephone: + 49 (0)441 9710-254
Focus of activities:
- Sustainability Reporting according to CSRD & ESRS, VSME (Certified Sustainability Reporting Specialist – Certificate)
- Supply Chain Management according to LkSG and EUDR
- Consulting on the EU Taxonomy Regulation
- Development of Sustainability Strategies including Goals and Measures
- Sustainability Trainings
About me
I completed my Bachelor’s degree in Social Sciences and Economics as well as the Master’s program in Sustainability Economics and Management at the University of Oldenburg.
After various interdisciplinary positions in the private sector as well as in research and development, I am primarily engaged in sustainability consulting and training at Treuhand Unternehmensberatung.
https://treuhand.de/app/uploads/2024/01/Sarah-Fasshauer_team.jpg 1200 1200 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-12-03 08:59:452026-03-03 10:31:03Sarah Faßhauer
Heiko
Günther
Attorney, Tax Lawyer
Telephone: +49 (0)441 9710-200
Focus of activities:
- Indirect Taxes (VAT), national and international Tax
- Cross-border Tax support
- Customs Law
About me
I joined the international tax law department of Treuhand in 2000. With a particular interest in cross-border transactions, I offer my clients pragmatic and solution-oriented advice on all matters of German and international tax law. More than 25 years of professional experience have enabled me to specialize in indirect taxes, in particular VAT and customs law. I have extensive experience in international tax planning as well as the establishment of German subsidiaries / branches and related issues. I also specialize in providing all-round advice to foreign companies operating in Germany or wishing to develop the German/European market.
In cooperation with the very personal network of HLB colleagues in over 150 countries, I provide concise and commercial advice to a very broad spectrum of clients, ranging from partnerships to listed companies. These include multinational companies – from the aerospace industry, e-commerce, mechanical engineering, shipbuilding and the clothing industry to freight forwarding/logistics companies.
Heiko Günther is partner at Treuhand Weser-Ems Wirtschaftsprüfungsgesellschaft.
https://treuhand.de/app/uploads/2023/12/team_guenther.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-17 11:16:322026-06-23 12:17:35Heiko Günther
Dr. Christian
Hansen
Lawyer, Tax Consultant, Specialist lawyer for tax law
Telephone: +49 (0)441 9710-200
Focus of activities:
- Tax and corporate law advice for companies
- Mergers & Acquisitions
- Business succession
- Tax redress procedures and tax court proceed
About me
Excellent legal and tax advice for medium-sized companies in the Weser-Ems region – that is my professional vision! My career began with my law studies in Münster, followed by my doctorate in international tax law and admission as a lawyer and specialist tax lawyer and finally the tax consultant exam in Bremen. As a native of Bremen, my heart beats for the Weser-Ems region, where I have been working professionally and living with my family for almost 20 years now.
I am a member of the Arbeitsgemeinschaft der Fachanwälte für Steuerrecht e.V., the Deutsche Steuerjuristische Gesellschaft e.V. and the Forum Rechnungslegung und Steuern in Bremen e.V. In addition to the restructuring of medium-sized companies, my professional focus is on issues relating to company acquisitions and company succession. Away from the office, I enjoy spending time with my family and taking part in sporting activities such as tennis and jogging. I am also involved in several charitable organizations in the region.
Dr. Christian Hansen is Managing Director at Treuhand Weser-Ems Wirtschaftsprüfungsgesellschaft and Partner at Treuhand Rechtsberatung Hochhäusler • Wurthmann & Partner, Partnerschaft von Rechtsanwälten mbB.
https://treuhand.de/app/uploads/2023/12/team_hansen.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-17 12:21:492026-01-09 10:32:23Dr. Christian Hansen
Tammo
Harms
Consultant, Graduate in Business Administration
Telephone: +49 (0)441 9710-0
Focus of activities:
- Finance and accounting
- Integrated planning
- Controlling
- Restructuring
- Start-up advice
About me
I provide consulting services with a focus on the development, establishment and implementation of processes and systems for number-based corporate management.
In addition, my core competencies lie in the areas of controlling, finance and accounting as well as crisis management. This also includes the preparation of restructuring concepts, also in accordance with the IDW S6 standard.
https://treuhand.de/app/uploads/2023/11/Tammo-Harms.webp 800 800 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-17 13:03:532025-03-10 11:03:46Tammo Harms
Alexander
Hamminger
Attorney, Tax Adviser
Telephone: +49 (0)441 9710-200
Focus of activities:
- Company, commercial and contract law
- Inheritance law and inheritance tax law
- Corporate succession and company sales
- Occupational pension provision
- Start-up advice
About me
More of a generalist than a specialist, I mainly advise medium-sized clients in northern Germany. I deal with all issues relating to the company and the entrepreneur, starting with the establishment of companies and ending with support in the termination of business activities. But I am also committed to advising entrepreneurs on the organization of company succession and the drafting of wills and powers of attorney.
Where I do not cover topics myself, I have the support of internal or external specialists. I also advise on data protection and money laundering issues. I like to spend my free time with my family, doing sports or cooking.
https://treuhand.de/app/uploads/2023/12/Hamminger-1.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-22 10:49:202025-03-10 11:38:59Alexander Hamminger
Habbo
Hartmann
Consultant, Graduate in Business Administration
Telephone: +49 (0)441 9710-0
Focus of activities:
- Finance and accounting
- Integrated planning
- Controlling
- Restructuring
- Start-up advice
About me
I advise with a focus on the areas of number-based corporate management (planning and controlling) as well as crisis management and the creation of corporate concepts. This also includes restructuring concepts in accordance with the IDW S6 standard.
In addition, my core competencies lie in the qualification of automobile trading companies in the areas of costs, finance, strategy and management. I have been an accredited specialist consultant for a German premium car manufacturer since 2007.
https://treuhand.de/app/uploads/2023/11/Habbo-Hartmann.jpg 800 800 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-17 13:08:262025-03-10 11:03:19Habbo Hartmann
Sven
Heinrichs
Auditor, Tax Adviser
Head of Bremen location
Telephone: +49 (0)421 223087-0
Focus of activities:
- Auditing of annual and consolidated financial statements in accordance with the German Commercial Code (HGB/IFRS)
- Tax planning and tax design
- Business consultancy
- Finance Advisory – Support services for issues in accordance with IFRS and the German Commercial Code
About me
“Audit is business with people” – this phrase still applies and can be extended to all our services – despite or perhaps because of digitalization. What I like about my work is the personal interaction – within the team and with our clients. This works particularly well because the lines of communication at Treuhand are short and decisions are made quickly. Even if data can be conveniently exchanged electronically, real personal impressions and good decisions are still best gained and made in face-to-face discussions.
As an experienced auditor and tax advisor, I enjoy solving particularly complex issues, both in the auditing and preparation of annual and consolidated financial statements in accordance with HGB and IFRS as well as in corporate tax planning and structuring or the preparation of due diligence. I am a member of the Institute of Auditors and the Chamber of Auditors and Tax Consultants. And when I’m not working? Then you’ll find me enjoying leisure activities with my family or on the tennis court.
Sven Heinrichs is Managing Director at Treuhand Weser-Ems Wirtschaftsprüfungsgesellschaft and Managing Director at VERITAS Treuhand GmbH & Co. KG Steuerberatungsgesellschaft.
https://treuhand.de/app/uploads/2023/12/Heinrichs-1.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-30 09:07:192026-01-09 11:22:01Sven Heinrichs
Ralf
Hochhäusler
Attorney, Tax Lawyer
Telephone: +49 (0)441 9710-200
Focus of activities:
- Corporation law and tax planning for companies
- Legal and tax succession planning, especially for family companies
- Tax defence advice including conducting proceedings in financial courts and the German Federal Fiscal Court
- Purchase and sales of companies and shares
About me
Fiduciary services are a recurring theme throughout my professional career. I laid the foundation stone with my training as a tax assistant at Treuhand. I then went on to study law at the University of Münster. During the semester breaks, I continued to apply and deepen my practical knowledge at Treuhand.
Having also spent part of my legal traineeship at Treuhand and having started working as a lawyer at Treuhand straight after my second state examination, I can say that I have never really left – true to my motto “Once at Treuhand, always at Treuhand”.
Ralf Hochhäusler is Managing Director at Treuhand Weser-Ems Wirtschaftsprüfungsgesellschaft and Partner at Treuhand Rechtsberatung Hochhäusler • Wurthmann & Partner, Partnerschaft von Rechtsanwälten mbB.
https://treuhand.de/app/uploads/2024/01/team_hochhaeusler.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-18 11:14:292026-01-09 11:22:26Ralf Hochhäusler
Jörg
Högemann
Consultant
Telephone: +49 (0)441 9710-254
Focus of activities:
- Lean management
- Strategy development
- Sustainability
- New Work transformation
- Coaching of change processes
- Organisation development
- Implementation of management systems
- Sustainability Management
About me
Thinking, working and living sustainably – that is important to me. My professional career began over 20 years ago during my studies in environmental sciences, with a focus on environmental management and environmental law, as a consultant for integrated management systems. Here I acquired well-founded qualifications that prepared me for my future career. The change to head of process and quality management in a special machine construction company enabled me to further deepen my experience in the areas of lean management, digitalization and leadership.
Almost 10 years ago, I founded my own management consultancy, which has been part of the Treuhand Group since 2020. Networking with the Treuhand team and our clients makes sustainable work even more efficient.
And that is exactly what drives me: Breaking new ground and shaping the future sustainably as well as networking our clients in the northwest to strengthen the region.
In my free time, I find balance in cooking, reading and music and enjoy discovering the world through the eyes of my children. I am also active in many networks and associations and am involved on a voluntary basis in OldTable, the Economic Council of the CDU, the Association of Family Entrepreneurs and the Advisory Board of AWV Jade, among others.
Jörg Högemann is Managing Director at Treuhand Weser-Ems Unternehmensberatung GmbH & Co. KG.
https://treuhand.de/app/uploads/2023/11/Hoegemann.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-04-17 12:37:182026-02-27 12:07:25Jörg Högemann
Christian
Loose
Attorney, Tax Adviser, certified advisor for international tax law, certified advisor for customs and excise duties
Telephone: +49 (0)441 9710-200
Focus of activities:
- Advice on VAT, customs, and excise duty matters
- Tax planning and structuring of cross-border activities, including permanent establishment issues, withholding taxes, and employee secondments
- Support with company incorporation and liquidation
- Contract drafting and negotiation
About me
My goal is to help clients move forward by providing clear, practical legal and tax advice.
I graduated from law school with distinction and began my career with an international tax advisory firm in Berlin following my legal traineeship. After qualifying as a Certified Tax Adviser, I decided to relocate to the Weser-Ems region.
I now live there with my family and spend much of my free time pursuing sporting activities.
I am a Certified Specialist Adviser for Customs and Excise Duties and a Certified Specialist Adviser for International Taxation. My practice focuses primarily on VAT, customs and excise duties, and international tax law.
https://treuhand.de/app/uploads/2024/01/team_loose.jpg 1080 1080 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2026-06-22 12:01:552026-06-23 10:27:02Christian Loose
Haimo Mader
Auditor, Tax Adviser, Sustainability AuditorIDW
Telephone: +49 (0)441 9710-0
Focus of activities:
- Auditing and preparation of annual and consolidated financial statements
- Tax and business management advice
- Active support, advice and structuring of financing (incl. discussions with banks)
- Auditing and consulting in the area of sustainability reporting in accordance with CSRD/ESRS
About me
My professional career began in 2008 after my military service with a dual study program at a cooperative bank, followed by work as a loan officer. In 2012, I switched to cooperative bank auditing. There I passed the association auditor, tax consultant and auditor exams. From the beginning of 2021 to the end of 2023, I worked as a department manager for banks in auditing and consulting topics.
By auditing the financing side at the banks, I was able to indirectly gain numerous and in-depth insights into a wide variety of industries, in particular the real estate and construction industry as well as the logistics sector including the maritime industry.
Since 2024, I have also been directly advising and auditing medium-sized companies in particular. My heart beats for the Weser-Ems region, where I have been working professionally for over 15 years and where I live with my family. Away from the office, I enjoy spending time with my family and getting some exercise.
Haimo Mader is partner at Treuhand Weser-Ems Wirtschaftsprüfungsgesellschaft.
https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg 0 0 Adriane Witt https://www.treuhand.de/app/uploads/2023/11/Treuhand-Logo-Blau.svg Adriane Witt2024-05-23 11:44:162026-01-09 11:23:20Haimo Mader