I just received a notification letter from my bank recently about the change in my housing loan interest rate, which is calculated in my case as 3-mth SOR + 1%. You can refer to this MoneySmart article about the difference between SIBOR and SOR. It also shows the SIBOR vs SOR historical chart, which I have included here for the fun of it. I follow the 3-mth SOR orange line closely simply because it directly affects my housing loan interest rate. And my monthly housing loan instalment payment happens to be my biggest expense every month. Sometimes, I compare it to the 3-mth SIBOR blue line just to see whether it would have been better to go for a SIBOR based housing loan. Turns out the 3-mth SOR orange line has been staying below the 3-mth SIBOR blue line so far for longer periods of time than having been above ......