Guide

Bonds and fixed income explained: yields, duration, and where debt fits in your portfolio

A bond is a loan. You lend money to a government, company, or other issuer; they promise to pay periodic interest (coupon) and return your principal at maturity. That predictable cash flow is why bonds are called fixed income — unlike stocks, which have no guaranteed payout, a bond contract spells out what you should receive if the issuer does not default. Bonds rarely make viral headlines, but they anchor trillions in pension funds, balanced portfolios, and emergency reserves. When interest rates rise, bond prices fall; when recession fears spike, high-quality bonds often rally while stocks sell off. This guide explains the mechanics — coupon vs yield, why prices move opposite to rates, duration as a risk measure, major bond types, funds vs individual bonds, and how to size fixed income alongside equities and crypto.

How a bond works: face value, coupon, maturity, and yield

Most bonds are issued at a face value (par) of $1,000 per unit, though institutional sizes are larger. The coupon rate is the annual interest percentage on that face value. A 4% coupon on $1,000 pays $40 per year, usually split into semi-annual payments of $20. At issuance, if market rates are also near 4%, the bond trades near par.

After issuance, the bond trades in the secondary market. Its price floats; its coupon does not. Yield to maturity (YTM) is the annualized return you would earn if you buy at today's price, collect all coupons, and hold until maturity when you receive $1,000 back. If you buy the same 4% coupon bond for $950 because market rates rose, your YTM is higher than 4% — you paid less for the same cash flows. If you pay $1,050 because rates fell, YTM is lower. This inverse relationship between price and yield is the single most important bond concept.

Current yield is simpler: annual coupon divided by current price. It ignores the gain or loss at maturity when price differs from par. Use YTM for hold-to- maturity decisions; current yield is a quick snapshot only.

Why bond prices move when interest rates change

Imagine you hold a bond paying 3% while newly issued similar bonds pay 5%. No rational buyer will pay full par for your 3% bond unless you discount the price — otherwise they could buy the new 5% issue instead. Your bond's price drops until its YTM approaches 5%. That is interest rate risk: existing bondholders lose market value when rates rise, even though coupon payments continue.

The sensitivity depends on duration — a weighted measure of how long until you receive the bond's cash flows. Longer-maturity bonds have higher duration and swing more in price for a given rate change. A rough rule of thumb: for every 1 percentage point rise in yields, a bond's price falls by about its duration in percent (e.g. duration 7 implies roughly -7% for a +1% rate shock). Duration is not the same as maturity — a 10-year zero-coupon bond has duration near 10; a 10-year bond with high coupons has lower duration because you get money back sooner.

Central bank policy drives these moves. When the Federal Reserve raises the federal funds rate, short-term yields climb first; longer yields follow if investors expect tight policy to persist. Bond investors watch the yield curve — the plot of yields across maturities — for recession signals and allocation cues.

Major bond types and who issues them

U.S. Treasury securities

Backed by the U.S. government, Treasuries are the global benchmark for "risk-free" nominal yield in dollars. T-bills mature in one year or less and pay no coupon — you buy at a discount to face value. T-notes span two to ten years; T-bonds go beyond ten years. TIPS (Treasury Inflation- Protected Securities) adjust principal with CPI, hedging inflation but often carry lower real yields. Treasuries have negligible credit risk; price risk from duration remains.

Investment-grade and high-yield corporate bonds

Companies borrow by issuing corporate bonds. Investment-grade issuers (rated BBB- or higher by agencies like Moody's or S&P) pay lower spreads over Treasuries. High-yield ("junk") bonds pay more to compensate for higher default risk. In recessions, credit spreads widen — prices fall beyond what rate moves alone would predict — and defaults cluster in weaker issuers.

Municipal bonds

U.S. state and local governments issue munis, often with tax-exempt interest for residents of the issuing state. That tax advantage makes after-tax yields attractive for high-income investors in taxable accounts. General obligation bonds pledge taxing power; revenue bonds depend on a specific project (tolls, utilities). Credit quality varies widely — not all munis are safe.

International and emerging-market debt

Sovereign bonds from other countries add currency and political risk. Emerging-market debt pays higher yields but can sell off sharply during global risk-off episodes. Currency hedging decisions materially change realized returns for U.S. investors.

Credit risk, inflation risk, and call risk

Credit risk is the chance the issuer misses payments or restructures debt. Rating downgrades usually push prices lower before default happens. Diversification across hundreds of issuers — via bond funds — reduces idiosyncratic blowups but not systemic credit crises.

Inflation risk erodes the real value of fixed coupon payments. A 4% nominal yield loses purchasing power if inflation runs at 5%. Equities and TIPS partially hedge inflation; plain nominal bonds do not. Real yields (nominal yield minus expected inflation) matter more than nominal headlines.

Call risk affects callable bonds: the issuer can redeem early when rates fall, forcing you to reinvest at lower yields. Callable bonds often pay higher coupons to compensate. Liquidity risk matters for individual bonds — thinly traded issues can have wide bid-ask spreads if you need to sell before maturity.

Bond funds vs buying individual bonds

Individual bonds offer a clear promise: hold to maturity, receive par (unless default). That psychological certainty breaks if you sell early at a market price. Building a diversified ladder of individual bonds takes capital and attention.

Bond mutual funds and ETFs pool many issues and rebalance continuously. They do not "mature" — NAV fluctuates daily with rates and credit spreads. A total bond market ETF might hold thousands of investment-grade U.S. bonds with a duration near 6–7 years. You get instant diversification and liquidity; you accept ongoing duration exposure. Our ETF guide covers fund structure and costs; broad bond ETFs often charge under 0.05% annually.

Target-maturity bond ETFs blend features: they hold bonds maturing in a specific year and distribute principal as that year approaches, behaving somewhat like a rolling ladder. They are newer but popular for dated goals (college, house down payment).

Where bonds fit in a portfolio with stocks and crypto

Stocks drive long-run growth; bonds provide ballast and income. The classic 60/40 portfolio — 60% equities, 40% bonds — is a starting point, not a law. Young investors with decades until retirement may hold less fixed income; retirees drawing spending from the portfolio often hold more. Our asset allocation guide walks through correlation, rebalancing, and sizing volatile satellites like crypto.

Bonds and stocks are not always negatively correlated. In 2022, both fell as rates rose from near-zero — a painful reminder that duration-heavy bond funds can lose double-digit percentages in a hiking cycle. Shorter-duration Treasuries or cash equivalents reduce that sensitivity at the cost of lower yield. Crypto has even weaker correlation stability; treat it as a small, speculative sleeve — not a bond substitute.

Practical building blocks for U.S. investors often include: a total U.S. bond market fund, a Treasury or investment-grade sleeve for safety, and optionally TIPS for inflation exposure. Taxable vs tax-advantaged account placement matters — munis in taxable accounts, Treasuries and corporate bonds in IRAs or 401(k)s where tax on interest is deferred.

Reading bond quotes and what to check before buying

Yield to maturity — your all-in return if held to maturity and no default.
Duration — approximate price sensitivity to a 1% parallel rate shift.
Credit rating and spread — yield premium over Treasuries; wider spread means more perceived risk.
Callable? — check yield-to-worst if the issuer can redeem early.
Expense ratio — for funds; a 0.20% fee on a 4% yield is a 5% drag on income.
Tax treatment — Treasury interest is state-tax-exempt; muni rules vary by state.

Bond math is slow and compounding. A 0.25% yield difference on a $100,000 allocation is $250 per year — meaningful over decades alongside equity returns. Do not chase the highest yield without reading the credit story behind it.

Common mistakes

Confusing coupon rate with yield after the bond has traded away from par.
Ignoring duration in a rising-rate environment — long bond funds can draw down like stocks.
Chasing high-yield funds without understanding default and recovery rates in downturns.
Assuming bonds always hedge stocks — correlation regimes change with inflation shocks.
Holding long-term bonds for money needed within two years — mismatch liquidity and duration.
Replacing an emergency cash reserve with a volatile bond fund.

Starter checklist

Define the job: ballast, income, or dated principal return.
Match duration to time horizon — shorter for near-term goals.
Prefer broad diversification via low-cost bond ETFs unless you have a specific ladder need.
Check real yields after expected inflation, not nominal yield alone.
Place tax-efficient instruments in the right account type.
Rebalance when equity rallies push your stock allocation above target — bonds are the usual source of funds.