Fixed-Income Security
Fixed-Income Security
Quick Definition
A fixed-income security is a financial instrument that obligates the issuer to make predetermined interest payments (typically called coupons) to the investor on a regular schedule and to return the original principal at maturity. Bonds are the most common fixed-income securities. The term "fixed income" reflects the contractually defined payment stream — unlike stocks, whose dividends are discretionary and prices variable.
What It Means
Fixed-income securities exist because borrowers (governments, corporations, municipalities) need to raise capital and investors want predictable income. The investor lends money; the borrower promises fixed periodic payments in return. This contractual certainty — knowing exactly how much interest you will receive and when — distinguishes fixed income from equity investing.
Fixed income serves multiple portfolio roles: generating regular income, preserving capital, reducing portfolio volatility, and hedging against equity market downturns. For retirees living on portfolio income, fixed income often forms the core of their portfolio.
Types of Fixed-Income Securities
| Type | Issuer | Risk Level | Typical Yield Premium |
|---|---|---|---|
| US Treasury bonds | US Federal Government | Lowest (risk-free rate) | Benchmark |
| TIPS | US Federal Government | Very low + inflation | Benchmark + real yield |
| Agency bonds | Fannie Mae, Freddie Mac, FHLB | Very low | +5-30 bps over Treasuries |
| Municipal bonds | State and local governments | Low-moderate | Tax-equivalent yield varies |
| Investment-grade corporate | High-rated corporations (BBB+) | Moderate | +50-200 bps over Treasuries |
| High-yield ("junk") bonds | Lower-rated corporations | High | +300-700+ bps over Treasuries |
| Convertible bonds | Corporations | Moderate (equity optionality) | Below straight bonds |
| Mortgage-backed securities (MBS) | Pools of mortgages | Low-moderate | +50-150 bps over Treasuries |
| Asset-backed securities (ABS) | Pools of auto loans, etc. | Variable | Variable |
| International bonds | Foreign governments/corporates | Varies; adds currency risk | Variable |
| Preferred stock | Corporations | Moderate | Higher than investment-grade |
Key Fixed-Income Concepts
Coupon Rate vs. Yield
| Term | Definition | Example |
|---|---|---|
| Face value (par) | Principal amount; typically $1,000 | $1,000 |
| Coupon rate | Annual interest as % of face value; fixed | 5% = $50/year |
| Coupon frequency | How often interest is paid | Semi-annual (most US bonds) |
| Maturity date | When principal is returned | 10 years from issuance |
| Current yield | Annual coupon / current market price | $50 / $950 = 5.26% |
| Yield to maturity (YTM) | Total return if held to maturity (IRR) | Accounts for price vs. par |
Price-Yield Relationship
Bond prices and yields move inversely — this is the most important fixed-income relationship:
| Scenario | Effect on Bond Prices |
|---|---|
| Interest rates rise | Existing bond prices fall (new bonds offer higher yields; old bonds become less attractive) |
| Interest rates fall | Existing bond prices rise (existing bonds paying higher coupons become more valuable) |
| Held to maturity | Investor receives all coupons + par value regardless of price fluctuations |
Example: You buy a 10-year bond with a 4% coupon for $1,000. If rates rise to 6%, new bonds pay $60/year vs. your $40. Your bond becomes less attractive — its market price falls to roughly $852 so that its YTM equals the new 6% market rate.
Duration: Measuring Interest Rate Sensitivity
Duration measures how sensitive a bond's price is to interest rate changes:
| Duration | Approximate Price Change per 1% Rate Move |
|---|---|
| 2 years | ~2% price change |
| 5 years | ~5% price change |
| 10 years | ~10% price change |
| 20 years | ~20% price change |
A bond fund with 7-year duration loses approximately 7% in price for every 1% rise in interest rates.
2022 example: The iShares 20+ Year Treasury ETF (TLT) has ~17-year duration. When rates rose ~3% in 2022, TLT fell approximately 32% — painful for investors who thought long-term government bonds were "safe."
Fixed-Income Credit Quality
Credit rating agencies assess the issuer's ability to make payments:
| Moody's | S&P/Fitch | Category | Default Risk |
|---|---|---|---|
| Aaa | AAA | Highest quality | Near zero |
| Aa1-Aa3 | AA+/AA/AA- | High quality | Very low |
| A1-A3 | A+/A/A- | Upper medium | Low |
| Baa1-Baa3 | BBB+/BBB/BBB- | Investment grade (lowest) | Low-moderate |
| Ba1-Ba3 | BB+/BB/BB- | Speculative (high yield begins) | Moderate |
| B1-B3 | B+/B/B- | Highly speculative | High |
| Caa-C | CCC-C | Near default | Very high |
| D | D | Default | In default |
The Fixed-Income Yield Spectrum (2024)
| Security | Yield |
|---|---|
| 3-month T-bill | ~5.35% |
| 2-year Treasury | ~4.60% |
| 10-year Treasury | ~4.30% |
| Investment-grade corporate (10-yr) | ~5.00-5.30% |
| High-yield corporate (5-yr avg) | ~7.50-8.50% |
| Municipal bond (10-yr, AA-rated) | ~3.50% (tax-equivalent ~5.5% at 37% bracket) |
| Emerging market sovereign | ~7-9% |
Key Points to Remember
- Fixed-income securities provide contractually defined interest payments (coupons) and return of principal at maturity
- Bond prices and yields move inversely — rising rates = falling bond prices
- Duration measures interest rate sensitivity — higher duration = greater price volatility when rates change
- Credit quality (AAA to D) determines default risk premium above the risk-free Treasury rate
- In 2022, long-duration bonds lost 30-40% as rates spiked — demonstrating that "safe" bonds carry real interest rate risk
- Fixed income plays the role of income generation, capital preservation, and equity hedge in diversified portfolios
Frequently Asked Questions
Q: Are bonds "safe"? A: It depends on which risk you mean. Short-term, high-quality bonds (T-bills, short-duration investment-grade) have very low default risk and low price volatility. Long-term bonds have significant interest rate risk — their prices can fall 20-40% when rates rise sharply. The "safety" of bonds must always be qualified by both credit risk and duration risk.
Q: What is the difference between a bond fund and individual bonds? A: An individual bond held to maturity returns par value regardless of price fluctuations — you receive your principal back. A bond fund has no maturity date — as rates rise, the fund's NAV falls and stays down indefinitely (it does not "recover" at maturity). For investors who need their principal back at a specific date, individual bonds offer certainty a fund cannot.
Q: Why do bond yields differ from coupon rates? A: The coupon rate is fixed at issuance. Yield changes as market interest rates change. When a bond trading at $900 pays a $50 coupon, the current yield is 5.56% even though the coupon rate is 5%. Yield-to-maturity also accounts for the gain of receiving $1,000 back at maturity after buying at $900 — the full picture of total return.
Related Terms
Government Bond
Government bonds are debt securities issued by national governments to fund spending, considered among the safest investments available because they are backed by the full faith and credit of the issuing government.
Bond
A bond is a fixed-income debt instrument where an investor lends money to a borrower (government or corporation) in exchange for regular interest payments and return of principal at maturity.
Asset Allocation
Asset allocation is the strategy of dividing a portfolio among different asset classes like stocks, bonds, and cash based on your goals, time horizon, and risk tolerance to optimize the risk-return trade-off.
Asset Class
An asset class is a group of investments that share similar characteristics, behave similarly in the marketplace, and are subject to the same laws and regulations — with the major classes being equities, fixed income, cash, real estate, and commodities.
Preferred Stock
Preferred stock is a hybrid security that combines features of stocks and bonds — offering fixed dividends paid before common stockholders but usually without voting rights, sitting in a middle tier between bondholders and common shareholders.
Investment Grade
Investment grade refers to bonds rated BBB-/Baa3 or higher by major credit rating agencies, indicating low default risk — these bonds are eligible for purchase by institutional investors such as pension funds and insurance companies that are restricted from holding speculative debt.
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