The substance of this research lies in answering whether and how the European and U.S. stock markets react to the upheaval caused by climate activists. Accordingly, we perform an event study on firms included in the Stoxx Europe 600 and S&P 500 to examine reactions to Global Climate Strikes by Fridays For Future. We analyze the significance of abnormal returns utilizing three event windows covering anticipation, short-term, and lagged effects and divide the sample according to environmental performance grades. Our findings reveal that climate strikes cause a general loss in firm value, exposing no profiteers. We identify differences in market reactions among both examined regions, particularly concerning the promptness of reactions. Enriching literature on stock market reactions, we prove that investors’ reaction is not limited to primary stakeholder events but also encompasses secondary stakeholder pressure. Furthermore, we provide evidence that climate activism has a processual character causing recurring effects on the stock market.