PENGARUH INFLASI TERHADAP KURS (Rp/US$)

This study aims to examine the effect of current period inflation and previous period inflation (lag 1 to lag 4) on the middle exchange rate of the Rupiah against the United States Dollar, as well as to evaluate the semi-strong form efficiency of the Indonesian foreign exchange market. This research utilizes a quantitative causal approach with monthly secondary data spanning from January 2021 to December 2025. The monthly inflation data (month-to-month) was obtained from Statistics Indonesia (BPS), while the Rupiah middle exchange rate data was acquired from Bank Indonesia. The analytical method used was distributed lag regression with a stepwise approach using SPSS software.The test results indicate that all inflation variables, both in the current period and lag 1 through lag 4, have no significant effect on the Rupiah middle exchange rate, individually or simultaneously. None of the variables met the significance criterion of p < 0.05 to be included in the regression model. Based on these findings, it is concluded that the Indonesian foreign exchange market was efficient in the semi-strong form during the study period, as public information in the form of inflation data had been fully absorbed into the exchange rate through market mechanisms. The results of this study support the concept of semi-strong market efficiency and provide implications for businesses, investors, Bank Indonesia, and future researchers in understanding the dynamics of the Rupiah exchange rate.exchange rate.