Return and risk analysis of the BIST 30 and Katılım 30 indices during the pandemic period

The changing and evolving structure of the financial world also affects portfolio compositions, requiring analyses and evaluations for more effective planning. This study comparatively examines the daily return and volatility structures of the BIST 30 and BIST Participation 30 indices during the period of December 2021 – May 2025, with a distinction between the pandemic (December 1, 2021 – May 5, 2023) and post-pandemic (May 6, 2023 – May 26, 2025) sub-periods. The daily returns and risks of both indices in the pandemic and post-pandemic periods have been compared. First, the daily returns of both indices were calculated and their averages were examined. The analyses indicate that there were no significant differences in average returns between the pandemic and post-pandemic periods. In other words, both indices provided investors with similar levels of gains. However, a different outcome emerged in terms of risk. Based on standard deviation calculations, it was observed that the BIST 30 index exhibited higher volatility than the BIST Participation 30 index in both the pandemic and post-pandemic periods. This shows that BIST 30 has a more fluctuating structure and entails greater risk for investors. In contrast, the BIST Participation 30 index demonstrated a relatively more stable trend.The results of the Mann-Whitney U test further supported these findings. In certain months, particularly during the pandemic period, shifts from positive to negative or negative to positive returns were observed in the indices. However, these changes were not consistently in the same direction. Overall, while no significant difference was found in terms of returns, the higher volatility of the BIST 30 compared to the BIST Participation 30 was statistically confirmed. In this respect, the BIST Participation 30 index offers a lower-volatility investment opportunity, aligned with Islamic finance principles.