ASBA (Application Supported by Blocked Amount) is a system developed by SEBI to make IPO applications safer for retail investors. When you apply for an IPO, the application amount is only blocked in your bank account, not debited.
Why is ASBA better?
Previously, investors had to write cheques, and refunds took weeks. With ASBA, you continue to earn interest on your blocked amount until the allotment day. If you don't get the allotment, the block is instantly released.
UPI vs ASBA
While UPI is extremely popular for IPO applications (up to ₹5 Lakhs), net-banking ASBA is often more reliable and less prone to mandate failures.