Bonds are the largest asset class in the world and the one most private investors understand least. The confusion usually starts with a single fact that sounds like a contradiction: a government bond can be certain to repay you in full and still lose a third of its value before it does.
That is not a defect. It is how the instrument works, and it is the first thing worth getting straight.
What you actually own
A bond is a loan you have made, split into tradable units. The issuer — a government, a company, a supranational institution — borrows a fixed amount, pays interest on a schedule, and repays the principal on a stated date.
Five terms describe every bond:
- Face value (par) — the amount repaid at maturity, conventionally 100.
- Coupon — the annual interest rate on the face value, paid on a fixed schedule.
- Maturity — the date the principal is returned.
- Price — what the bond trades for today, which is usually not 100.
- Yield — the return you actually earn if you buy at today's price and hold to maturity.
Coupon and yield are different numbers and confusing them is the most common beginner error. The coupon is fixed at issue and never changes. The yield moves every day, because the price moves.
Buy a bond with a 3% coupon at a price of 100 and your yield is 3%. Buy the same bond at 90 and your yield is higher — you get the same coupon plus a capital gain of 10 at maturity. Buy it at 110 and your yield is lower.
Price and yield move in opposite directions
This relationship is arithmetic, not sentiment, and it is the single most important thing to understand about bonds.
You hold a ten-year bond paying 3%. Rates rise, and newly issued ten-year bonds pay 4%. Nobody will buy your 3% bond at par when a 4% one is available at par, so your bond's price falls until its total return to maturity matches the market. For a ten-year bond that adjustment is roughly 8%.
Nothing about the issuer changed. No payment was missed. The bond simply became less attractive relative to the alternatives, and the price is what adjusts.
Duration measures how much. As a working approximation, a bond loses its duration in percent for every one percentage point rise in yields.
- Duration 2: a 1% rise in yields costs about 2%.
- Duration 7: about 7%.
- Duration 20: about 20%.
The 2022 tightening cycle demonstrated this on a scale most investors had never seen. Long-dated government bonds fell 20% to 30% in a year. Nothing defaulted. The portfolios that were hurt were the ones holding long maturities because that is where the yield was.
A second-order effect, convexity, means the relationship is not perfectly linear: prices rise slightly more when yields fall than they fall when yields rise by the same amount. It works in the holder's favor and it matters most on long maturities.
The shapes government debt comes in
Sovereign issuers slice their borrowing by maturity, and the names differ by country while the structure does not.
Short-dated paper — up to a year, typically issued at a discount with no coupon. You pay 98 and receive 100. US Treasury bills, UK Treasury bills, German Bubills. This is the cash-equivalent end: minimal price risk, whatever the prevailing short rate is.
Medium and long-dated bonds — two to thirty years, paying regular coupons. US Treasury notes and bonds, German Bunds, UK gilts, Japanese government bonds, French OATs, Italian BTPs. These are where duration risk lives.
Inflation-linked bonds — the principal is adjusted by a price index, so the coupon and the redemption both rise with inflation. US TIPS, UK index-linked gilts, and equivalents elsewhere. They protect purchasing power rather than nominal value, which is a different guarantee from the one most investors assume they are buying.
Floating rate notes — the coupon resets periodically against a reference rate, so the price stays close to par while the income moves. They remove duration risk and give you rate risk in the income stream instead.
The five risks
Credit risk is the chance the issuer does not pay. Ratings agencies grade it from AAA down to D, with the investment-grade boundary at BBB−. Below it, bonds are called high yield or, more honestly, junk, and they behave much more like equities than like government paper. Credit risk is the risk everyone thinks about and, for developed-market sovereign debt in its own currency, the smallest one.
Interest rate risk is duration, described above, and it is the risk that actually hurts most portfolios. It is entirely a function of maturity and it is knowable in advance.
Liquidity risk is the chance you cannot sell at a fair price. Benchmark government bonds trade in enormous size with tiny spreads. Small corporate issues, older off-the-run government bonds and anything unusual can be expensive to exit, and the cost shows up exactly when you need to sell.
Inflation risk is the quiet one. A 3% coupon with 5% inflation is a guaranteed loss of purchasing power delivered with perfect reliability. Nominal bonds protect the number, not what the number buys.
Reinvestment risk is the mirror image: if rates fall, the coupons you receive get reinvested at lower rates than you assumed. It is the reason a yield to maturity is a projection rather than a promise unless you hold a zero-coupon bond.
And for anyone holding foreign bonds, currency risk sits on top of all of it — frequently larger than the yield advantage that motivated the purchase in the first place.
How bonds are bought and sold
The primary market is issuance. Governments sell new debt at auction on a published calendar. Large institutions submit competitive bids specifying the yield they require; smaller investors, where the facility exists, can submit non-competitive bids and accept the average price. Auction results are watched closely, because weak demand for a country's debt is market-moving information about that country.
The secondary market is where everything trades afterwards. This is where prices move, where yields are set, and where almost all volume happens.
One mechanical detail catches people out. Bond prices are quoted clean, excluding interest that has accrued since the last coupon date. What you pay is the dirty price: clean price plus accrued interest. Buy halfway between coupon dates and you compensate the seller for their half. It is not a fee, and you get it back at the next coupon, but the settlement amount will be higher than the screen price and it is better to know that before the confirmation arrives.
Building a bond allocation
Start from what the money is for, because that determines maturity more than any yield forecast does.
Matching. If you need a specific sum on a specific date, buying a bond that matures then removes market risk entirely. Price moves in between are irrelevant if you hold to maturity, and this is the one situation where the "bonds are safe" intuition is straightforwardly correct.
Laddering. Split the allocation across maturities — one, two, three, four, five years — so something matures every year and is reinvested at the prevailing rate. A ladder gives you a rolling average of the rate environment instead of a bet on one point in it, produces predictable liquidity, and removes the need to forecast. It is the single most useful structure for a private investor and it requires no view about anything.
Barbell. Combine very short and very long maturities, skipping the middle. The short end provides liquidity and reinvestment optionality; the long end provides yield and convexity. It behaves differently from a ladder when the yield curve changes shape rather than level.
Duration as a dial. Longer maturities pay more and hurt more when yields rise. That is the whole trade-off, and it should be set deliberately based on horizon and tolerance rather than by picking the highest number on the screen.
Diversification across issuers and currencies reduces single-country risk, and introduces currency risk in exchange. For most investors, hedged exposure or home-currency issuance is the simpler answer.
Bonds against the alternatives
Deposit accounts pay a fixed rate with no price risk and, up to the local guarantee limit, no credit risk. They are simpler and often competitive at short maturities. What they lack is the capital gain a bond delivers when rates fall — a deposit cannot appreciate.
Bond funds and ETFs give instant diversification and small minimums, and they differ from individual bonds in one way that matters enormously: a fund has no maturity date. An individual bond held to maturity returns par regardless of what happened in between. A fund continuously rolls its holdings, so a period of rising yields produces a loss that is only recovered through higher future income, not by a redemption date. Investors who bought bond funds in 2021 expecting bond-like safety learned this in 2022.
Target-maturity bond ETFs are a hybrid: a fund that holds bonds maturing in the same year and liquidates then, which restores the redemption date while keeping diversification.
The mistakes that cost the most
Treating bonds as risk-free. They are default-free, at best, and only for the strongest sovereigns in their own currency. Default risk and price risk are different things and the second one is the one you will actually experience.
Reaching for yield. The bond paying substantially more than its peers is paying for a reason: worse credit, longer duration, poorer liquidity, or an embedded call option that lets the issuer redeem early when it suits them. Higher yield is compensation for risk, never a free upgrade.
Ignoring inflation. A nominal return that fails to beat inflation is a real loss, delivered with certainty. This is precisely the scenario in which bonds feel safest and perform worst.
Buying long maturities for the income. Yield-hungry investors buy thirty-year bonds because the coupon is highest, then discover the duration. If the money might be needed before maturity, the maturity is the risk.
Assuming a fund behaves like a bond. The distinction above is worth stating twice, because it is the single most common structural misunderstanding in retail fixed income.
Why a currency trader should care
Bonds are not a detour for anyone trading foreign exchange. They are the transmission mechanism.
Exchange rates over horizons of weeks to months are driven substantially by yield differentials — the gap between what two countries' government bonds pay. Capital flows toward the higher risk-adjusted yield, and the currency has to be bought to get there. The two-year yield spread between two countries usually explains more of their exchange rate's direction than any technical pattern.
Which means bond prices are not a separate market. They are a leading indicator for currency direction, and the yield curve is where a central bank's expected path is written down before it happens. Understanding how a bond is priced is understanding how a rate decision reaches every other asset.
The instrument, not the reputation
Bonds do a specific job well: they generate predictable income, they return a known amount on a known date, and in most downturns they hold value better than equities do.
What they do not do is remove risk. Between purchase and maturity a bond is a traded asset whose price responds to rates, credit and liquidity like anything else, and the investor who bought it believing otherwise is the one who sells at the bottom.
Choose the maturity for the horizon, know the duration before buying, treat a high yield as a question rather than an opportunity, and remember which of the risks you are actually being paid to take. That is most of fixed income, and none of it requires forecasting rates.
