This study describes and analyzes the performance issues that can arise in corporate transactions (Mergers & Acquisitions). A particular focus is placed on examining the risks faced by the seller. There is often uncertainty regarding whether and to what extent a seller of a company may be liable due to breaches of pre-contractual obligations (such as disclosure duties). The question of whether a seller can be held liable for poor performance according to the provisions of the German Civil Code (BGB) also requires further discussion. This study aims to contribute to greater clarity on this matter through an analysis of current case law and literature. It will also explain the potential impacts of conducting due diligence in this context.