Abstract: The purpose of this study is both to release the effects of the current pandemic on emerging equity markets and to examine the efficacy of the prevention policy to lessen the plausible negative effects. In this context, Turkey, as an emerging market, is examined by adopting the Regression Discontinuity Design which is a robust non-experimental approach for evaluating the causal effects of interventions. The results of the research reveal that the COVID-19 pandemic is effective in Bourse Istanbul after a certain period when it first appeared in the world. And therewithal, the efficiency of preventing policy taken in the country statistically decreased the negative impact of the pandemic.