After completing vocational training as a bank clerk, Stefan Sickinger studied business administration at the University of Würzburg, specializing in business taxation, accounting and auditing, corporate finance, and banking and credit management. He graduated with a degree in business administration (Diplom-Kaufmann).

After his studies, Stefan Sickinger worked for six years at a Big Four auditing firm, during which he passed the tax advisor exam.

He has been with KSP since 2015 and became a partner in the firm in 2025. His main areas of expertise include advising international companies operating in Germany (inbound cases), corporations, and partnership structures.