If you don’t maintain a sufficient balance on the due date, your SIP installment will fail and get reversed, meaning the investment for that month won’t go through. However, you can manually make an additional purchase if you still wish to invest for that instalment.
Additionally, your bank may charge a penalty or non-sufficient funds (NSF) fee for the failed transaction, depending on their policies. To avoid any inconvenience, extra charges, or disruptions in your SIP, ensure your account has enough balance before the due date.