Your free ATM withdrawal fee quota resets to SGD $400 at midnight SGT on the 1st of each calendar month.
Unfortunately, you are unable to carry forward your unused free ATM withdrawal quota to the following month. If the free quota of SGD$400 for the month is completely unused or only partially used, it would simply reset at the start of the month.
Example 1: In the month of June, with no ATM withdrawals made, the SGD$400 free ATM withdrawal quota will lapse at the end of the month and the quota would reset to SGD$400 on the 1st of July.
Example 2: In the month of June, when an ATM withdrawal of SGD $10 was made, the remaining free quota of SGD $390 will lapse at the end of the month and the quota would reset to SGD $400 on the 1st of July.