Accrued interest is the interest earned on a bond between coupon payments. This page explains how it is calculated, why buyers pay it to sellers at the point of purchase, how it affects bond pricing through the clean and dirty price, and how it appears on the balance sheet.
Definition and Core Concept
Accrued interest refers to interest that has been earned or incurred over time but has not yet been paid or received in cash. It reflects the accumulation of interest income or expense under the accrual method of accounting, where transactions are recorded when they occur rather than when money changes hands.
In the world of fixed-income securities—especially bonds—accrued interest has a very specific role. It represents the portion of the upcoming coupon payment that has accumulated since the last interest payment date. When a bond is bought or sold between coupon dates, this accrued interest must be transferred from the buyer to the seller. Understanding this concept is essential for interpreting bond pricing, income allocation, and financial reporting. It also appears on balance sheets as either an asset or a liability, depending on whether interest is receivable or payable.
How Accrued Interest Is Calculated
The calculation of accrued interest follows a simple structure: take the bond’s face value, multiply it by the annual coupon rate, and then adjust for the fraction of the coupon period that has passed.
In formula terms:
Accrued Interest = Face Value × Coupon Rate × (Days Since Last Payment ÷ Days in Coupon Period)
The number of days used depends on the applicable day count convention. The face value is typically the principal amount of the bond (often 1,000 in many markets), and the coupon rate is the annual interest rate stated on the bond.
For instance, consider a bond with a face value of 1,000 and a 6% annual coupon paid semi-annually. Each payment equals 30. If the bond is sold halfway through a 90-day period (after 45 days), the accrued interest would be:
30 × (45 ÷ 90) = 15
This amount is paid by the buyer to the seller at the time of the transaction.
Accrued Interest in Bond Transactions
Bonds are typically traded between coupon payment dates. The quoted price in the market—known as the clean price—does not include accrued interest. However, the total amount the buyer actually pays, called the dirty price (or invoice price), includes accrued interest.
Dirty Price = Clean Price + Accrued Interest
This system ensures fairness. Since the next full coupon payment goes entirely to the bondholder on record at the payment date, the seller must be compensated for the time they held the bond since the last payment. Without this adjustment, trading behavior would become inefficient, with sellers waiting until after coupon dates and buyers avoiding purchases before them.
From the buyer’s perspective, the accrued interest paid is not an additional expense—it is effectively reimbursed when the full coupon is received. Only the portion corresponding to the buyer’s holding period represents true income.
The Role of Day Count Conventions
Day count conventions determine how time is measured for interest calculations. Different markets and instruments use different standards:
Actual/Actual: Uses the exact number of days in both the numerator and denominator; common for government securities.
30/360: Assumes each month has 30 days and each year has 360 days; widely used for corporate and municipal bonds.
Actual/360: Counts actual days elapsed but divides by 360; often used in money markets.
Actual/365: Uses actual days over a 365-day year; common in some international markets.
These conventions can slightly affect the accrued interest calculation.
Accrued Interest on the Balance Sheet
In accounting, accrued interest appears as either:
Accrued interest receivable (asset): Interest earned but not yet collected.
Accrued interest payable (liability): Interest incurred but not yet paid.
Under accrual accounting principles, interest must be recorded in the period it is earned or incurred, regardless of when the payment is actually made.
Accrued Interest from the Issuer’s Perspective
For the bond issuer, accrued interest represents a growing obligation between coupon dates. Each day increases the amount owed to bondholders. This obligation is recorded as a liability and is settled when the coupon payment is made.
Accrued Interest vs Accrued Income
Accrued interest is a specific type of accrued income. While accrued income includes all earnings recognized before cash receipt (such as rent or fees), accrued interest refers strictly to interest-related earnings or expenses.
Tax Treatment of Accrued Interest
Tax handling depends on the accounting method used:
Cash-basis taxpayers (most individuals): Recognize interest income when it is received. However, accrued interest paid at purchase reduces taxable income because it is included in the first coupon received but does not represent earned income.
Accrual-basis taxpayers (typically corporations): Recognize interest as it accrues over time, regardless of payment timing.
Accrued Interest in Practice: Example
Suppose an investor buys a bond with:
Face value: 10,000
Coupon rate: 5%
Payment dates: January 1 and July 1
The investor purchases the bond on March 1, which is 60 days into the coupon period. Using a 30/360 convention, the total period is 180 days.
The semi-annual coupon is:
10,000 × 5% ÷ 2 = 250
Accrued interest:
250 × (60 ÷ 180) = 83.33
The buyer pays this amount in addition to the bond’s clean price. On July 1, they receive the full 250 payment, of which 83.33 is simply reimbursement, and the remaining 166.67 is actual earned income.
Key Takeaways
Accrued interest is the interest accumulated since the last coupon payment.
Buyers compensate sellers for this amount when bonds are traded between payment dates.
The clean price excludes accrued interest; the dirty price includes it.
Day count conventions determine how the interest is calculated.
Proper understanding is crucial for bond valuation, accounting, and financial analysis.
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