Why bond prices fall when yields rise

The coupon stays fixed while the comparison moves

Imagine a hypothetical $1,000 bond paying $30 annually. Its coupon rate is 3% of face value. If new comparable bonds begin offering more attractive payments, buyers will not necessarily pay the same $1,000 for the older bond. A lower market price increases the return available from buying its fixed payment stream.

A price of $900 would make the $30 annual coupon roughly 3.33% of the purchase price. That is current yield, not yield to maturity. The latter also considers the timing of payments and the difference between purchase price and principal repayment. Do not report the coupon divided by price as though it captured every part of the investment’s return.

Time changes the sensitivity

A payment far into the future is exposed to changes in discount rates for longer than a payment arriving soon. All else equal, a longer-duration fixed-rate bond tends to be more sensitive to yield changes. Duration summarizes that sensitivity; it is not simply another name for the years until maturity.

The same one-percentage-point yield move can therefore produce different price changes across two bonds. Coupon size, maturity and embedded options can all matter. A rough duration-based estimate is useful for a small change, but it is an approximation and can become less reliable for large moves or securities with changing cash-flow patterns.

Holding to maturity does not remove every risk

For an ordinary bond paid as promised, holding to maturity avoids having to realize an interim market-price decline through a sale. But this does not erase inflation, issuer default, reinvestment or opportunity-cost risk. It also assumes the investor can avoid selling earlier and that the bond’s terms do not change the expected path through a call or another provision.

A bond fund is a different object from a single bond with a known maturity. Funds may continually replace holdings, and an ordinary open-ended fund does not promise to return one investor’s original purchase amount on a personal maturity date. Read the fund mandate and duration rather than borrowing assumptions from a single-security example.

Use a complete return calculation

A bond investment’s outcome combines income, changes in price, fees and any reinvestment effects. If interest rates rise, existing holdings may fall in price while future purchases offer higher yields. Whether that trade-off helps a particular investor depends on timing and cash needs; it cannot be settled by calling rising yields simply good or bad.

For the next bond headline, write down coupon, maturity, market yield, credit quality and whether the instrument is a bond or a fund. Then specify the time horizon of the comparison. The central relationship remains useful: for otherwise comparable fixed cash flows, price and required yield move in opposite directions. That relationship is a starting point for analysis, not a promise that every bond-like product behaves identically.

The part I would check first is whether the money might be needed before the bond matures. A discussion about receiving scheduled payments can miss the very different experience of having to sell while market prices are lower.