01 The core trade
Prepaying is investing — at your loan's rate
Every dollar of prepayment "earns" exactly your mortgage rate, with zero risk and zero drama. That's the honest frame: a guaranteed 2.6% on an HDB loan, or 1.4–1.8% on today's bank fixed packages. Against that stands a diversified portfolio's long-run ~9% average — earned unreliably, through crashes you have to sit through.
| Where the extra dollar goes | What it "earns" | Certainty |
|---|---|---|
| Prepay bank loan (1.4–1.8%) | 1.4–1.8% | Absolute |
| Leave it in CPF OA | 2.5% | Government floor |
| Prepay HDB loan (2.6%) | 2.6% | Absolute |
| Diversified global portfolio | ~9% long-run average | None in any given year |
Note the quiet oddity mid-2026: bank mortgage rates sit below the CPF OA floor — cheap debt by any historical standard, which stacks the deck further against prepaying a bank loan.
02 Sized honestly
The same $500/month, for 20 years
Illustrative: $500/month for 20 years ($120k). Prepayment value = interest avoided plus the freed instalments, equivalent to compounding at 2.6%. The gap to investing is $50k–$100k — the price tag on certainty.
For your money: at these spreads, prepaying an HDB loan costs you roughly $50k–$100k per $500/month of expected wealth over 20 years — and prepaying a 1.5% bank loan costs even more. Certainty is a real good; just buy it knowing the sticker price.
For your life: the maths assumes you'd actually invest the difference — and stay invested through the ugly years. If the honest answer is that the "invested" money would leak into lifestyle or get sold in a panic, the mortgage's boring guarantee quietly wins. Know your own behaviour before you cite the averages.
03 The local wrinkle
The CPF wrinkle: which dollars you prepay with
- OA cash vs mortgage: OA earns a guaranteed 2.5%; an HDB loan charges 2.6%. Prepaying with OA "earns" you a net 0.1% — barely worth the button-press, and it drains the buffer that could pay your instalments through a retrenchment.
- Every OA dollar you use accrues 2.5% against your future sale proceeds — the interest you owe yourself. Prepaying with cash instead leaves OA compounding and keeps that snowball smaller.
- Bank-loan holders: check the lock-in first — prepaying during a fixed period typically costs 0.75–1.5% of the sum, which can wipe out years of the "return". HDB loans have no penalty at all.
04 The trap inside the comfort
Home equity is a roach motel for cash
Here's what the peace-of-mind framing skips: money sent into the flat is gone as money. You can't sell one bedroom in a bad year. Getting it back means selling the home, or borrowing against it at whatever rates prevail on your worst day. A prepaid flat plus an empty buffer is a fragile kind of safety — the disaster the prepayment was guarding against is exactly when you'll miss the cash.
Emergency fund full → protection in place → high-interest debt gone → long-term investing running. Prepayment competes for the last dollar, not the first. A mortgage is the cheapest money you will ever borrow; treat retiring it as a luxury purchase, made from surplus.
05 The honest other side
The case for paying it off anyway
- The return is real and unconditional — 2.6% guaranteed beats most "safe" instruments outright, and no market year can take it back.
- Debt-free changes behaviour. People who clear the mortgage often save more afterwards, take braver career decisions, and sleep better — effects no spreadsheet captures but every household feels.
- Approaching retirement, the maths converges. With a shorter horizon, equities' average matters less and their variance more; entering retirement with no instalment is a genuine de-risking, not just a feeling.
- At today's bank rates it's almost free to wait — which cuts both ways: if rates ever climb back above 4%, prepaying becomes a strong "investment" again. The answer is allowed to change with the spread.
06 The honest summary
A fair rule for a personal question
The spread is wide (it is, mid-2026), your buffer and protection are solid, retirement is 15+ years off, and you genuinely leave investments alone in red years.
The loan rate climbs toward your realistic after-cost returns, retirement is near, the debt weighs on you daily — or the "invested difference" keeps not getting invested.
Split answers are legitimate: many households invest the spread through their forties, then glide the mortgage to zero as retirement approaches. Sequencing that glide — alongside CPF, SRS and the rest — is exactly the kind of thing worth an hour together. How I help →
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Sources & notes
Figures as of June–July 2026. HDB loan rate (2.6%, no prepayment penalty): HDB. Bank fixed packages (~1.4–1.8%, some lower; lock-in penalties typically 0.75–1.5%): published rate boards — check your own letter of offer. CPF OA floor (2.5%) and housing accrued-interest mechanics: CPF Board. Global equity long-run average (~9% nominal, MSCI World since 1987, USD): index data — past returns are not promises, currency and costs reduce them. The 20-year illustration is ours: $500/month compounded at 2.6% / 5% / 7%, assumptions stated so you can disagree precisely.
General information, not financial advice. The right split depends on your loan, horizon, buffer and temperament. Jonathan Wong is a licensed financial adviser representative in Singapore, currently between firms — during that period he is not able to provide financial advice. You can check his registration yourself on the MAS Financial Institution Representatives Register at eservices.mas.gov.sg/rr.