Our history 

Since 1958, we have been supporting our clients in realizing their business objectives. We are particularly familiar with the challenges of dynamic growth for the German Mittelstand as we went down this road ourselves in our 60 years of history. We started out as an owner-managed national audit firm and have become an international stock corporation with over 130 partners.

04 May 1958: Foundation of Warth & Klein GmbH by Karl Warth, Günter Klein and Werner Klein in Düsseldorf. 

1991: Inauguration of the Company’s office in Leipzig after the German reunification 

2000: The Company joins the Grant Thornton International Ldt. network 

2001: Inauguration of the Company’s office in Frankfurt am Main 

2007: Inauguration of the Company’s office in Stuttgart 

2010: Conversion into a stock corporation 

2011: Warth & Klein becomes sole German member firm of the Grant Thornton International network and changed its name to Warth & Klein Grant Thornton AG Wirtschaftsprüfungsgesellschaft as of 01 July 2011  

2011: New partners joined Warth & Klein Grant Thornton and inauguration of the Company’s offices in Hamburg and Munich 

2015: Inauguration of the new offices at Johannstrasse, Düsseldorf 

2017: Inauguration of the Company’s office in Berlin 

2018: Cooperation with Hanse Consulting Group (until 2023)

2018: Merger with Nachmann Rechtsanwälte in Munich 

2019: Merger with Trinavis, Berlin becomes the second largest location after Düsseldorf 

2020: Merger with the locations of PKF Fasselt Schlage in Hamburg and Rostock.

2022: Relocation of Frankfurt offices to the 18th/19th floor in the Senckenberg Tower  

2022: As of 01 March 2022, the Company’s name was changed to Grant Thornton AG Wirtschaftsprüfungsgesellschaft 

Who we are

Our history

From an owner-managed national audit firm to an international stock corporation with over 130 partners.

Read more Our history

Our responsibility

Meaningful success is achieved when we work together for the benefit of all those we serve.

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Our goals

Further information on our corporate goals.

Read more Our goals