The concept of Service-oriented Architecture (SOA) is becoming increasingly important not only in research, but also in practice. SOA has emerged as a major topic, especially in regards to the banking industry as it is one of the cutting-edge industries concerning service-orientation. SOA implementation in the German banking industry varies, with some still in the adoption phase and others already in the SOA operations phase. This has specific implications concerning the SOA Readiness as well as the SOA Maturity of German banks. This paper details the research objective, design, and conduction of a case study in the Germany banking industry investigating the SOA Readiness and SOA Maturity of German banks. Different phases such as SOA adoption and SOA operations and the consequences of SOA during Merger & Acquisition (M&A) conduction are analyzed and evaluated. Finally, the preliminary findings are exhibited.