Coupon Rate vs. Yield: What's the Difference?
A bond’s paperwork lists an interest rate right on it, which makes it tempting to assume that number is the whole story. It usually isn’t, and the gap between what’s printed and what’s actually earned trips up a lot of new bond investors.
The short answer
A bond’s coupon rate is the fixed interest payment set when the bond is issued, expressed as a percentage of its face value. Yield is the actual return an investor earns based on what they paid for the bond, which can be more or less than face value. When a bond trades at anything other than face value, coupon rate and yield diverge.
How the coupon rate is set
When a bond is first issued, its coupon rate is set based on prevailing interest rates and the issuer’s perceived creditworthiness at that moment. For most fixed-rate bonds, this rate never changes for the life of the bond — it’s locked in at issuance and determines the fixed dollar payments the bondholder receives on a set schedule until maturity.
Why yield moves even though the coupon doesn’t
Once a bond starts trading in the secondary market, its price can rise or fall based on shifts in interest rates, the issuer’s credit standing, and general demand. The coupon payment stays the same dollar amount regardless of price, but yield reflects that fixed payment relative to what an investor actually paid. If a bond is purchased below its face value, the fixed coupon payments represent a larger percentage return relative to the lower purchase price, so yield is higher than the coupon rate. If purchased above face value, yield is lower than the coupon rate. This is part of why bond premium versus bond discount pricing matters so much to actual investor returns.
A simple illustration
Imagine a hypothetical bond with a fixed coupon rate that pays a set dollar amount each year, issued at its face value. If interest rates in the broader market rise after issuance, new bonds start offering higher coupon rates, making the older, lower-fixed-rate bond less attractive at its original price. Its market price would need to fall for its yield to become competitive with newer bonds — which is exactly why bond prices fall when interest rates rise. The coupon rate on the older bond never changes, but its yield to a new buyer, purchasing at the now-lower price, moves up to reflect current conditions.
Where else this distinction matters
- Comparing bonds at a glance. Two bonds with identical coupon rates can offer very different yields if one is trading well above or below face value.
- Understanding total return. Yield gives a more complete picture of what an investor stands to earn than the coupon rate alone.
- Evaluating par value versus market value. The relationship between a bond’s face value and its trading price is the mechanical reason coupon rate and yield can differ.
The bottom line
The coupon rate tells you what a bond promises to pay in fixed dollar terms; yield tells you what that promise is actually worth given the price paid. Both matter, but yield is generally the more useful figure for comparing bonds against each other or against other investments, since it accounts for the price actually paid rather than an unchanging number printed at issuance.