You all no need to use OA to pay for mortgage one ah
Well, let's check some "back of the envelope" math....
Let's suppose that a hypothetical married couple consists of one working spouse earning S$5,000 per month (S$65,000 per year with "13th month" and/or other variable pay) and another working spouse earning S$6,000 per month (S$72,000 per year). We'll assume they're both 37 years old, and they own an HDB BTO flat. Let's assume the BTO flat was S$320,000 (after housing grants), and they financed 80% (S$256,000) using a 25 year HDB loan at 2.6% p.a.
In this scenario the monthly mortgage payment would be about S$1,162. The couple's total annual compulsory CPF contributions would be S$50,690, of which at least S$28,777 would land in their CPF Ordinary Accounts. (Maybe more if both their MA and SA have high balances.) That's an average of S$2,398 per month in total Ordinary Account inflow to cover a S$1,162 mortgage payment leaving an accumulating surplus of S$1,236 per month. If the couple splits the mortgage relative to their respective incomes then both of them will cross the S$20,000 mark in their OAs within a couple years even if they're both starting from zero OA balances.
They can then invest some or all dollars above S$20,000 via the CPF Investment Scheme (OA). S$40,000 of total OA savings would allow them to pay their S$1,162 per month mortgage for about 35 months (nearly 3 years) even if there were an utterly catastrophic family emergency resulting in the total loss of BOTH incomes — and even without tapping their growing CPF Investment Scheme (OA) assets.
Isn't this scenario realistic?