Dirty Price

Investors who purchase fixed-income instruments, such as bonds, anticipate receiving coupon payments on a predetermined timetable. The present value of a bond's future coupon payments, however, determines its price. The price of a bond will probably include interest that has accumulated since the coupon payment date, unless the bond is bought on that date.

As a result, the seller will pocket the interest, which would be a dirty price, and the buyer will miss out on one coupon payment. A clean price, in contrast, does not include any accumulated interest.

Understanding Dirty Price

A coupon bond accrues interest when it is currently between coupon payment dates. The amount of interest that has accumulated up until the next coupon payment date rises daily. Since no interest will be accumulated until the next market day, the clean price and dirty price are equal on the day of the coupon payment.

The dirty price may also be referred to as the price plus incurred. The clean price is more frequently quoted in the United States, whereas the dirty price is the norm in Europe.

Accrued Interest

A bond's interest accrues daily, with an increase in interest rate that is constant. As a result, up to the payout date or coupon payment date, the dirty price will fluctuate every day. The clean and dirty prices are equal after the payout is done and the accrued interest is reset to zero

The filthy price would increase significantly each day over the course of six months for bonds with semiannual installments. The accrued interest resets to zero to start the cycle over after the six-month point and the coupon payment. Up until the bond's maturity, the dirty-to-clean procedure is repeated.

Dirty Vs. Clean Pricing

Brokers and investors frequently exchange dirty prices, but the clean price, or the price before interest has been charged, is typically regarded as the advertised price. Newspapers or financial resources that track prices are likely to publish the clean price. Although accumulated interest is included in the filthy price, the clean price is frequently thought of as the bond's value in the current market.

How To Calculate Dirty Price?

Dirty Price

We only need to add the accumulated interest to the clean price to determine the dirty price.

The formula is as follows:

Dirty Price = Clean Price + Accrued Interest

Clean Price

Simply separating the impact of the accumulated interest from the filthy price allows us to get the clean price.

The formula would be as follows:

Clean Price = Dirty Price – Accrued Interest

Key Takeaways

• In addition to a bond's coupon payment, a filthy price also includes accumulated interest.
• The price given for a bond that quotes in between coupon payment periods includes interest that has accrued as of the quote date.
• A dirty bond price, as contrast to a clean bond price, contains accumulated interest.
• While in Europe, dirty quotes are the norm, clean quotes are more common in the US.