Purpose – Since base interest rate change information affects stock prices with a time lag, the purpose of this study is to identify how much it affects stock returns for a certain period of time based on the base rate change date. Design/Methodology/Approach – The research method analyzed the effect of changes in the base interest rate, level of the base interest rate, and increase/decrease on stock investment performance with the stock index for ±20 days of base rate change from 2008 to November 2022. Findings – Stock returns for a certain period of time before and after the base rate change date were -0.33% in Korea and -1.08% in the US, respectively. The United States showed -1.46% and -0.70%, respectively. The daily stock return for a certain period was -0.02% in Korea and -0.04% in the US, and the daily stock return before and after the release of the base rate change was -0.07% and 0.03% in Korea and -0.09% and -0.01% in the US, respectively. appear. At the level of the base rate, in Korea, the base interest rate of 0.75% had lower interest rate, but the rate of return was negative, and the base rate of 1.25%, 1.75%, and 2.25% had both positive and negative rates of return. In the US, interest rates of 0.0% and 0.25% were low, but yields were negative, and rates of interest of 1.25% and 1.75% were both positive and negative. Research Implications – By empirically analyzing the impact of changes in the base interest rate on stock returns, it is to establish what investors should pay attention to when the central bank changes the base rate.