First, you'll need to spend a minimum of S$500 on any eligible UOB Credit card monthly. Once you've fulfilled this criterion, your monthly interest earned will depend on the size of your monthly average balance. When you hit the minimum credit card and debit card spend, you can unlock bonus interest rates of up to 2.50% p.a. by fulfilling any of these criteria: Credit card spend + salary credit Credit card spend + at least 3 GIRO transactions