The topic of this thesis is a comparison of the global economic crisis and the crisis caused by the COVID-19 pandemic on the American capital market. The goal is to provide an understanding and analytical comparison of these two major crises that shaped the beginning of the 21st century. Through the impact of these two significant crises on the American capital market, the similarities and differences in their causes, consequences, and responses of regulatory authorities were identified. The Global Economic Crisis focused on the real estate market collapse, the excessive leverage of financial institutions, and regulatory shortcomings. In parallel, the COVID-19 crisis is analyzed, highlighting its abruptness and global impact, which resulted in sharp market declines, but also rapid recovery thanks to strong government interventions. The thesis addresses research questions such as how different causes of crises affect investors' decisions and market behavior, and whether the cause of the crisis affects the form of intervention by government and financial institutions. By comparing the crises, their differences and similarities in impact are highlighted, as well as government interventions, especially regarding regulation and preparedness for crises. A concluding consideration of the long-term consequences of these crises on US stock markets and the broader economic and social implications offers recommendations for future market stability and resilience, contributing to a deeper understanding of the complex dynamics between crisis causes, market reactions, and regulatory responses. Through a comprehensive analysis of historical crises, it is possible to develop a more resilient and sustainable financial system for the future.