Accrued Interest (Bond) Singapore: Why You Pay More Than the Quoted Price
Accrued interest is the interest that has built up on a bond since its last coupon payment date, which a buyer must pay to the seller when purchasing a bond between coupon dates. For Singapore Government Securities (SGS), it is added to the quoted clean price to produce the dirty price actually paid at settlement.
Not financial advice. All figures for educational reference only. Data as at July 2026.
Key Takeaways
- Accrued interest compensates the bond seller for the portion of the current coupon period they held the bond before selling it.
- For SGS bonds, interest generally accrues from the previous coupon date, inclusive, to the settlement date, exclusive.
- The formula is: accrued interest equals the coupon per period multiplied by the number of days since the last coupon, divided by the number of days in the full coupon period.
- The dirty price, sometimes called the invoice price, is the clean quoted price plus accrued interest – it is the actual amount a buyer pays.
- MAS provides an SGS bond calculator that estimates accrued interest and the resulting dirty price for any SGS bond and settlement date.
What Is Accrued Interest?
Most bonds pay a fixed coupon every six months. If a bond changes hands partway through a coupon period, the buyer will receive the full upcoming coupon payment on the next payment date, even though they only held the bond for part of that period. To keep things fair, the buyer compensates the seller upfront for the days the seller actually held the bond within the current period – this compensation is accrued interest.
Accrued interest applies whenever an SGS bond, corporate bond, or similar coupon-paying instrument is bought or sold in the secondary market, or when purchasing a reopened bond at auction partway through its coupon cycle. It does not apply to zero-coupon instruments like T-bills, since they carry no periodic coupon to accrue.
How Does Accrued Interest Work in Singapore?
For SGS bonds, MAS specifies that interest accrues from the previous coupon date (inclusive) up to the settlement date (exclusive), using an actual/365 day-count convention. The calculation is: accrued interest equals the coupon amount for the period, multiplied by the number of days elapsed since the last coupon, divided by the total number of days in that coupon period.
| Term | Meaning |
|---|---|
| Clean price | The quoted market price of the bond, excluding accrued interest |
| Accrued interest | Interest earned by the seller since the last coupon date |
| Dirty price | Clean price plus accrued interest – the actual amount the buyer pays |
Source: MAS Monetary Authority of Singapore, “Accrued Interest and Dirty Prices” guidance, as at July 2026.
Accrued Interest Example
An SGS bond pays a semi-annual coupon of S$25 per S$1,000 face value (equivalent to a 5% annual coupon rate). If an investor buys the bond 60 days into a 182-day coupon period, the accrued interest owed to the seller is approximately S$25 multiplied by 60 divided by 182, or about S$8.24 per S$1,000 face value. If the quoted clean price is S$990, the buyer actually pays a dirty price of roughly S$998.24 at settlement.
Why Understanding Accrued Interest Matters
- Avoids confusion at settlement – investors who only look at the quoted clean price may be surprised by a higher total amount due at purchase.
- Fair compensation ensures sellers are not penalised for holding a bond through most of a coupon period only to receive nothing at sale.
- Useful for comparing bonds bought at different points in their coupon cycle, since the clean price alone does not reflect the full cost.
- Relevant for tax and accounting purposes in some contexts, since accrued interest received or paid may need to be tracked separately from capital gains.
- MAS provides a public bond calculator so retail SGS investors do not need to calculate accrued interest manually.
Risks and Limitations
- Easy to overlook – investors focused only on a bond’s advertised yield or clean price may underestimate the true cash outlay required at purchase.
- Day-count conventions vary between bond types and markets, so the exact accrued interest formula can differ for non-SGS or foreign bonds.
- Does not affect total return if held to maturity in a simple sense, but does affect the timing and size of the initial cash outlay, which matters for cash flow planning.
- Reduces apparent capital gain on resale, since part of the sale proceeds reflects accrued interest rather than a genuine price gain.
Accrued Interest vs Clean Price vs Dirty Price
| Concept | What It Represents | Who Uses It |
|---|---|---|
| Clean price | Quoted market price, excludes accrued interest | Displayed on trading platforms and news quotes |
| Accrued interest | Interest owed to seller for days held since last coupon | Calculated separately at each settlement |
| Dirty price | Clean price plus accrued interest | The actual invoice amount paid by the buyer |
The Bottom Line
For Singapore bond investors, accrued interest is the reason the amount you actually pay for a bond – the dirty price – is almost always higher than the clean price you see quoted. Understanding the distinction avoids surprises at settlement and makes it easier to compare bonds fairly regardless of where they sit in their coupon cycle.
Frequently Asked Questions
What is the difference between clean price and dirty price?
The clean price is the quoted market price excluding accrued interest, while the dirty price is the clean price plus accrued interest – the actual amount a buyer pays at settlement.
Do I need to pay accrued interest when buying an SGS bond?
Yes, if you buy between coupon dates on the secondary market or buy a reopened bond at auction, you compensate the seller for the interest accrued since the last coupon payment.
Does accrued interest apply to Singapore T-bills?
No – T-bills are zero-coupon instruments with no periodic coupon, so there is no accrued interest to calculate; the entire return is embedded in the discount to face value.
How can I calculate accrued interest on an SGS bond myself?
MAS provides a public SGS bond calculator that estimates accrued interest and the resulting dirty price for a given bond and settlement date, removing the need for manual calculation.
Does receiving accrued interest count as taxable income in Singapore?
Singapore does not tax capital gains or most interest income for individual investors, but investors with specific tax situations should consult a tax professional for their circumstances.