Öz
Volatility in the prices of financial assets significantly affects portfolio risks and investment returns. For this reason, it is important to model the volatilities, determine the causes and predict them. In this study, it is aimed to analyze Borsa İstanbul 100 index return with the Markov switching approach. In the study, it was used to data that BIST 100 index, USD ($) / Turkish Lira (TRY) exchange rate and 2-year government bond interest rates for the period of January 4, 2010 - December 30, 2019. It was observed that two different regimes, high volatility and low return as well as low volatility and high return, in the study. The 1st regime represents the bear market and the 2 nd regime represents the bull market. Average stay time (64) in regime 2 is higher than average stay time (11) in regime 1. The probability of switching to regime 2 is more than the probability of switching to regime 1. While the exchange rate has an effect on the 1st regime, this effect disappears in the 2nd regime. The effect of the interest rate was seen in both regimes. The results are usable to investors, portfolio managers and risk managers.