Price vs. yield: what a bond’s market value is actually telling you.

A Treasury pays a fixed coupon and returns face value on a fixed date. So when a statement shows that same Treasury marked down 4%, it raises a fair question: what exactly is that number measuring?

The answer is that it’s measuring something real, but something different from what a hold-to-maturity investor receives. The market value is what the bond would fetch if sold today. The yield to maturity is what it pays if held. Those two numbers diverge whenever rates move, and a statement only shows you the first one.

It’s worth understanding why they diverge, because the mechanics make clear which number applies to which situation.

Why bond prices move opposite to rates

A bond is a fixed set of payments. Once purchased, the coupon is locked and never adjusts. What moves is what newly issued bonds are paying — and an existing bond has to compete with them in the secondary market.

Take a 5-year Treasury paying 4%. A year later, new 5-year Treasuries are being issued at 5%. Consider the buyer’s position: why pay full price for a 4% bond when a newly issued one pays 5%?

They wouldn’t. So the price adjusts downward until the total return to a buyer — the discount at purchase, plus the coupons, plus full face value at maturity — is competitive with that 5% alternative. The bond didn’t deteriorate. The alternatives improved.

The reverse holds as well. If new issues drop to 3%, the 4% bond becomes the more attractive instrument and trades above face value. Same bond, same payments — different rate environment around it.

Three numbers, three different questions

Bond discussions move between three figures that sound interchangeable and aren’t. Separating them resolves most of the ambiguity.

The coupon rate never changes. A 4% Treasury pays 4% of face value every year regardless of what happens to rates, to its market price, or to anything else. That’s worth stating directly, because a declining market value has no effect on the interest payments arriving in the account.

Yield to maturity is the figure that matters for a hold-to-maturity position, and it differs from the coupon whenever a bond is purchased at anything other than par. A 4% bond bought at $96 yields more than 4% — the buyer collects the coupons and the $4 pull toward face value at maturity. A 4% bond bought at $104 yields less, for the mirror-image reason.

This is also why the convergence toward par isn’t a market prediction. It’s built into the instrument: the discount or premium at purchase is itself part of the return, and it is fully realized only at maturity.

Why longer maturities move more

The same rate move affects bonds unevenly depending on how much time each has left. A portfolio holding several maturities will show a much larger mark on the long-dated positions than the near-term ones, on the same day, from the same shift in rates. That sensitivity is duration, and it follows from the arithmetic above.

A bond maturing in twelve months has one year of below-market coupons to discount before it pays face value. A bond maturing in ten years has ten. The longer the remaining term, the more that rate difference accumulates — and the larger the price adjustment required to bring the total return in line with what’s currently available.

So a bond maturing next year barely registers a rate move, while one maturing in 2035 can move several percent. Both mature at face value. They simply take different paths getting there.

What the price actually does over time

This is where a statement’s snapshot becomes misleading, because it omits the most important structural feature of an individual bond: the price is anchored.

Whatever rates do in the interim, a Treasury matures at face value. That isn’t a forecast or a probability — it’s the terms of the instrument. Price can move above and below par as rates shift, but it converges back to 100 cents on the dollar as maturity approaches. It has to; on the maturity date, the two figures are the same number.

A simplified illustration — a $100,000 Treasury paying 4%, through a period of sharply rising rates:

Hypothetical illustration for educational purposes only. Values are approximate and rounded, assume a constant coupon, and do not reflect taxes, fees, or transaction costs. Not indicative of any actual holding or result.

The middle column shows a loss for four consecutive years — at one point exceeding $6,000. The right column never moves. An investor holding to maturity collected every coupon on schedule and received the full $100,000 at maturity. The interim marks were accurate as market values and immaterial to the outcome.

Market value answers what the bond is worth to a buyer today. Yield to maturity answers what it pays to the holder at term.

Yield to maturity: the number that actually applies to you

At purchase, a bond locks in a yield to maturity — the total annualized return realized by holding to the end. Absent a U.S. government default, that figure was determined on the trade date and doesn’t change afterward.

Everything price does between now and then is the market valuing that bond for a different holder — someone whose entry point, time horizon, and alternatives differ. It’s the resale value of a contract held to term. For a hold-to-maturity investor, the market’s valuation in month 14 doesn’t enter the outcome.

This is why unrealized price movement within a ladder doesn’t drive our decisions. The relevant variables — the coupon, the maturity date, the yield locked in at purchase — are unchanged.

Why this is different from a bond fund

This distinction is structural rather than a matter of opinion, and it’s the reason the same rate move affects the two differently.

An individual bond has a maturity date. A bond fund does not.

A fund holds a rotating pool of bonds, continuously buying and selling to maintain a target duration. No date exists on which the fund matures and returns principal at par. When rates rise and the share price falls, there is no contractual pull back toward a fixed value — recovery depends on rates retracing, or on reinvestment at higher yields closing the gap over time.

Both are legitimate tools with different applications. But they behave differently in precisely this scenario, and individual Treasuries carry something a fund cannot: a date certain.

Why a ladder makes this easier to live with

A Treasury ladder holds individual bonds maturing at staggered intervals — one year, two years, three, and so on. That structure does two things when rates rise.

First, maturities arrive continuously. Rather than a single distant maturity date, cash returns to the account at par on a regular schedule, available for income or reinvestment.

Second, rising rates cut both ways. The market value of longer rungs declines — while each maturing rung is reinvested at the new, higher rate. The same move that pressures the statement value raises the income the ladder generates going forward.

When the price does matter

There are three situations where market value is the operative number, and they’re worth stating plainly:

Selling before maturity. A bond liquidated early transacts at market price — and if rates have risen since purchase, that means realizing a loss. This is why a ladder is structured around anticipated cash-flow needs, so that early liquidation is rarely required.

Opportunity cost. Holding a 4% bond to maturity while new issues pay 6% carries a genuine economic cost, even with principal returned in full. That’s a legitimate consideration in deciding whether to hold or reposition — it is a different question from whether a loss has occurred.

Credit deterioration. With corporate or municipal issuers, a falling price may reflect doubt about repayment itself — a fundamentally different problem from a rate-driven mark. For U.S. Treasuries, this consideration is generally regarded as minimal.

A rate-driven mark on a Treasury held to maturity falls into none of those categories. It reflects the arithmetic of discounting a fixed payment stream at a higher rate — nothing more.