This thesis highlights the gap in previous literature and research of activist short selling in the context of the Swedish market. This thesis investigates the impacts of short sell research reports on the Swedish financial markets, aiming to provide a comprehensive understanding of the dynamics, implications, and outcomes related to this phenomenon. The study is conducted through empirical research involving semi-structured interviews, allowing for in-depth exploration and understanding of various perspectives, with investor relations representatives from targeted firms, legal experts, analytics and short sell research firms. From our empirical findings key research questions are addressed.  Firstly, the study examines the market dynamics and industry-specific factors driving increased attention from short sell research firms towards Swedish companies, highlighting factors such as market volatility, valuation challenges, and transparency concerns. Secondly, it explores how the emergence of short sell research reports shapes market dynamics, investor behaviour, and market integrity, noting both positive contributions to market efficiency and challenges regarding the accuracy and validity of the reports. Thirdly, the responses of targeted companies to allegation made in these reports are analysed, emphasizing the importance of a prompt, transparent response to maintain investor confidence. Fourthly, concerns about market manipulation are evaluated, considering the regulatory framework and the need for balance between market freedom and regulatory oversight.  This thesis contributes insights into market dynamics, conflicts of interest in financial analysis, and regulatory mechanisms, offering practical recommendations for stakeholders, including targeted companies, investors, and regulatory authorities. The recommendations from the study focuses on enhancing transparency, communication strategies, and regulatory compliance. Overall, this thesis enriches the understanding of short sell activism and its impact on financial markets, offering valuable insights for practitioners, researchers, and regulators.