This should not be shocking if you see some of the other discussions here.This data point is shocking.. means they will go by the lowest point of the day too!Last year I topped up $4000 on 1st Jan, and that was shown as the transaction date. So My MA balance was $75,500 for the full year, but my interest was $3,006.70, which is 4% on $71,500 for 1 month plus 4% on $75,500 for 11 months. Topping up on 1st Jan didn't earn me interest on the top up amount in Jan.
From the CPF website:
"CPF interest is computed monthly. It is credited to your respective accounts by the following year and compounded annually.
CPF balances used for interest computation are affected by the transactions in your account. For instance, contributions (including refunds) received this month start earning interest next month. Withdrawals/deductions in this month will not earn interest from this month onwards."
Yes, you need to top up before contributions from your employer or any refunds come into the MA in January, but it doesn't have to be the first day (you'd lose any interest that you'd earn on the cash in your bank account, though it is really tiny, I know). For retirees, can wait till the end of the month.
Eg 8am is 19k at 12pm increased to 20k but they still take 19k to compute yet gaining the 1k to freely use... omg
A lot of people should know that CPF interest is calculated this way, so it makes more sense to do contributions close to the end of the month.