The financial watchdog has put banks on notice for overcharging millions of dollars in extra interest payments for some customers with mortgage offset accounts. Some Australian mortgage-holders have been paying millions of dollars extra in interest payments because banks failed to manage offset accounts properly, the financial watchdog has found. Offset accounts are marketed to borrowers as a way to chip away at their mortgages and cut down on interest payments. Between September 2023 and August 2025, banks paid more than $55 million in customer compensation for offset account failures. ASIC chair Sarah Court said the issue should ‘concern every bank offering offset accounts’.