I have a Time Deposit Account with the Krungsri Bank. When it matures the bank teller ends that term and you get a balance in your bank book at that moment of 0, just for a few seconds. The teller then re-enters it as 800,000 deposit for a new term. The IO only sees the 0 balance. I have now deposited a further 400,000 baht, so I have 1,200,000 balance. When the 800,000 matures it will still show a balance of 400,000 for those few seconds, the minimum allowed.