more than 100 employees, 6 locations, 1 shared passion



As of 2020, Jan Trenn is leading CELLS Group’s strategy and expansion efforts. Jan offers longstanding management expertise in the strategic positioning of service and media companies. Prior to joining CELLS, Jan Trenn acted as General Manager and CFO of a media company group. Before that he held various management positions within the IT and business consulting industry.



Norman Schaaf joined the CELLS Group in 2003 and is responsible for the acquisition, supervision and marketing of development projects, along with the optimisation and development of the company’s existing property portfolio. Prior to joining the company, Mr. Schaaf spent 13 years with a property development company based in Leipzig, and was also self-employed. During this period he successfully implemented a wide range of development projects involving heritage-protected residential and business buildings.



Dirk Ruppert joined the CELLS Group in early 2013 and is in charge of investment management for individual and institutional clients of CELLS Property Investors. Before joining the CELLS Group, Mr. Ruppert spent 13 years as a Fund Manager for pension funds, insurance companies and various wealthy private individuals, during which he invested, managed and divested assets worth over 2.5 billion euro throughout Europe.

General Manager - Asset Management


Thomas Ostermann joined the CELLS Group in the summer of 2016. As a member of the Executive Board, he is responsible for asset management of the company’s own property portfolio as well as those belonging to individual and institutional clients of CELLS Property Investors. Mr. Ostermann’s position includes responsibility for planning the value retention and appreciation of properties, along with their operational implementation. His former positions include a 10-year period in charge of a nationwide commercial property portfolio for a publicly-listed real estate company.

General Manager - Property Management


Andrea Zengler has been with the CELLS Group since 1997. In her role as a realtor, she is in charge of property and facility management, which involves managing the property portfolio of both CELLS and third parties. She is also active in the optimisation and development of the company’s existing property portfolio.

General Manager - Construction Egineering


Jürgen Wodianka works since 2001 for CELLS Group. As civil engineer, he is responsible for the construction department and manages both any improvements for existing buildings in our portfolio as well as the planning and implementation for development projects.