Purpose: This study aims at determining the existence and, if any, the extent of comparative effects of the CDS premium and the VIX index on the BIST-30 and the Participation-30 indices before and during the pandemic. Methodology: The study explores the relationships of the CDS premium and VIX index to the BIST-30 index and the Participation-30 index for two time periods, as pre-pandemic and pandemic. The date range is set as 02.01.2018-10.03.2020 for the pre-pandemic period and as 11.03.2020-31.12.2021 for the pandemic period. Following the Johansen cointegration and ARDL tests employed to detect the long run relationships between the variables, FMOLS regression tests were used to determine the effect sizes. Results: As a result of the cointegration tests, long-term cointegration relationships of both the BIST-30 and the Participation-30 indices with the variables of the CDS premiums and the VIX index were determined before and during the pandemic period. FMOLS regression results posited that the VIX index had greater effect on the Participation 30 index in both periods. Originality and Practical Implications: The fact that the literature review does not reveal the existence of any study providing the comparative effects of the CDS premiums and the VIX index on both the BIST-30 and Participation-30 indices contributes to the originality of this paper.