In recent years, traditional banks in Indonesia have been facing numerous challenges which require banks to have a good health level to survive. although it is logical to assume that BUKU IV is the best performer among other BUKU groups due to its large core capital, it needs to be statistically proven. Therefore, this study aims to examine the impacts of RBBR ratios on the stock returns of the two largest BUKU groups-BUKU III and BUKU IV--and compare both results. This study uses five independent variables: NPL. LDR, ROA, NIM, and CAR; one control variable, bank size; and the dummy variables, BUKU III and BUKU IV. This study also uses a purposive sampling technique to determine the research sample. The RBBR analysis is used to examine the banking health level of each RBBR ratio and multiple regression analysis is performed for testing the hypotheses. The first result of this study shows that BUKU IV was healthier regarding NPL, LDR, ROA, and NIM than BUKU III whereas the latter was healthier in terms of CAR compared to BUKU IV. Meanwhile, ROA had a negative effect and CAR had a positive impact on stock returns of BUKU III and BUKU IV. It is also noted that there was no difference between the stock returns of BUKU III and the stock returns of BUKU IV.