How Bond Accrued Interest Works and How It Is Calculated

What Is Accrued Interest?

When bonds are bought or sold between coupon payment dates, the buyer compensates the seller for the interest that has accumulated up to that point. This amount is known as accrued interest. Even though coupon payments are made on specific dates, interest accumulates every day the bond is held.

This article explains accrued interest meaning, what accrued interest is, how it is calculated, and includes a clear example to help you understand it.

Accrued interest is the interest that has accumulated on a bond between coupon payment dates. Even though a bond pays interest periodically—monthly, quarterly, semi-annually, or annually—the interest is technically earned daily.

When a bond changes hands between coupon dates, the buyer pays the seller the interest that has accrued until that day.

Accrued Interest Meaning

Accrued interest represents the portion of the upcoming coupon payment that the seller has already “earned” by holding the bond for part of the coupon period.

In simpler words:

• It is the interest built up from the last coupon date

• It reflects the number of days the seller has owned the bond since the last payment

• It ensures that interest is allocated fairly between buyers and sellers.

Why Accrued Interest Exists in Bonds

Accrued interest exists for two main reasons:

Fairness between buyer and seller:

The seller held the bond for a portion of the coupon period and is entitled to the interest accumulated during that time.

Accurate pricing:

Bond markets need a consistent way to price bonds traded between coupon dates. Accrued interest ensures pricing reflects both principal value and accumulated interest.

How Bond Accrued Interest Is Calculated

Accrued interest is calculated using a simple proportional method:

• Identify the coupon rate

• Determine the coupon payment frequency

• Count the number of days since the last coupon payment

• Apply the bond’s day-count convention (e.g., Actual/Actual, 30/360)

• Accrued interest grows daily until the next coupon date.

Accrued Interest Formula

The standard accrued interest formula is:

Accrued Interest=Coupon Payment×Days Since Last CouponDays in Coupon Period\text{Accrued Interest} = \text{Coupon Payment} \times \frac{\text{Days Since Last Coupon}}{\text{Days in Coupon Period}}Accrued Interest=Coupon Payment×Days in Coupon PeriodDays Since Last Coupon​

Where:

• Coupon Payment = (Coupon Rate × Face Value) ÷ Number of payments per year

• Days Since Last Coupon = Actual number of days passed

• Days in Coupon Period = Total days between coupon dates (based on the day-count method)

This formula ensures interest is split fairly among investors.

Example: What Is Accrued Interest (With a Simple Illustration)

Example Scenario A bond has:

• Face value: ₹1,000

• Coupon rate: 8% annually

• Coupon frequency: Semi-annual (twice a year)

• Last coupon date: 1 January

• Today’s date: 1 March

• Day-count method: Actual/Actual

Step 1: Calculate the coupon payment

• Coupon Payment=1,000×8%÷2=₹40\text{Coupon Payment} = 1{,}000 \times 8\% \div 2 = ₹40Coupon Payment=1,000×8%÷2=₹40

Step 2: Count the days

• Days since last coupon: 59 days (1 Jan–1 Mar)

• Total coupon period days: 181

Step 3: Apply the formula

• Accrued Interest=40×59181≈₹13.05\text{Accrued Interest} = 40 \times \frac{59}{181} \approx ₹13.05Accrued Interest=40×18159​≈₹13.05 This ₹13.05 is paid by the buyer to the seller in addition to the bond’s clean price.

Day-Count Conventions in Accrued Interest

Different bonds use different day-count conventions. These affect how interest accrues.

Common day-count methods include:

• Actual/Actual: Uses actual days in each period

• 30/360: Assumes each month has 30 days and each year has 360 days

• Actual/360 or Actual/365: Used for some corporate or money market instruments

Accrued interest calculations vary depending on which convention applies.

Accrued Interest on Bonds Sold Between Coupon Dates

When selling a bond between coupon dates:

• The seller receives accrued interest for the days they held the bond

• The buyer pays this accrued amount during settlement

On the next coupon payment date, the buyer receives the full coupon, even though part of it was earned by the seller. Accrued interest ensures this is handled fairly.

This separation of:

• clean price (price excluding accrued interest)

• dirty price (price including accrued interest)

is standard in bond markets.

How Accrued Interest Affects Bond Pricing

Accrued interest doesn’t change the value of the bond itself—it simply adjusts the transaction amount.

A bond’s clean price reflects its market valuation.

A bond’s dirty price reflects the:

• market valuation

accrued interest up to settlement

This ensures the coupon payment is allocated fairly between the previous holder and the new holder.

How Investors Can View Bond Details on BondScanner

BondScanner provides access to issuer details, coupon schedules, maturity dates, credit ratings, and other key characteristics.

Information on coupon periods and cash-flow structures—when disclosed in offer documents—helps investors understand how accrued interest may build during the bond’s life cycle.

Investors can explore bonds and compare characteristics as part of their independent research using the information available.

Conclusion

Accrued interest ensures that interest earned between coupon dates is allocated fairly when bonds change hands. It reflects the time the seller held the bond and ensures the buyer pays the appropriate amount for accumulated interest.

By understanding accrued interest meaning, the accrued interest formula, and examples of how interest accrues daily, investors can better interpret bond pricing and settlement calculations.

Disclaimer

This blog is intended solely for educational and informational purposes. The bonds and securities mentioned herein are illustrative examples and should not be construed as investment advice or personal recommendations. BondScanner, as a SEBI-registered Online Bond Platform Provider (OBPP), does not provide personalized investment advice through this content.

Readers are advised to independently evaluate investment options and seek professional guidance before making financial decisions. Investments in bonds and other securities are subject to market risks, including the possible loss of principal. Please read all offer documents and risk disclosures carefully before investing.