Why Coupon Rate and Yield to Maturity Are Different
When a bond is first issued, its coupon rate and yield to maturity are the same — the bond sells at face value. But once it starts trading in the secondary market, prices change while the coupon payment stays fixed. A bond with a 4% coupon that now trades at $9,200 (below its $10,000 face value) actually yields 5.7% to maturity — because you're paying $9,200 for $10,000 back at maturity plus all the coupon payments.
This distinction matters enormously for investment decisions. Looking only at the coupon rate on a secondary-market bond is like looking at a stock's dividend yield without considering the stock price. The yield to maturity (YTM) is the true annualized return if you hold to maturity, accounting for: the annual coupon payments, the gain or loss from the price difference vs. face value, and the time value of money.
Duration is the other critical concept for bond investors. Modified duration measures how much your bond's price changes for each 1% change in interest rates. A bond with a modified duration of 7 loses approximately 7% of its market value if rates rise 1%. In a rising rate environment, long-duration bonds are far more volatile than short-duration bonds — even at the same coupon rate.
For most individual investors, the practical takeaways: buy individual bonds primarily if you plan to hold to maturity (eliminating price risk), use YTM to compare bonds and alternatives rather than coupon rates, and keep duration short if you're concerned about rate increases.
Calculate Your Bond's True Yield
Enter the bond's face value, coupon rate, current price, and maturity to calculate YTM, after-tax yield, and price sensitivity.
Calculate Bond YTMHow to Evaluate a Bond Investment
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Calculate yield to maturity, not just current yield
Current yield (annual coupon ÷ price) is a quick measure but ignores the price-to-face-value gain or loss at maturity. YTM accounts for everything. For a discount bond (price < face value), YTM > current yield. For a premium bond (price > face value), YTM < current yield. Always evaluate bonds on YTM for apples-to-apples comparison.
- 2
Assess credit risk relative to yield
Bonds are rated by Moody's, S&P, and Fitch. Investment-grade bonds (BBB-/Baa3 and above) have lower default risk but lower yields. High-yield ('junk') bonds (BB+/Ba1 and below) pay more but carry real default risk — in recessions, default rates can spike to 10–15% for the lowest-rated bonds. The yield spread over comparable Treasuries should compensate for credit risk. If the spread is thin, you're not being paid enough for the risk.
- 3
Understand interest rate risk (duration)
Modified duration tells you the price sensitivity. A 10-year bond with 7 years of modified duration loses 7% of market value for each 1% rise in rates. This matters only if you might sell before maturity — if you hold to maturity, you'll receive face value regardless of interim price changes. Match bond duration to your investment horizon: if you need the money in 3 years, hold bonds with 3-year or shorter duration.
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Compare YTM against risk-free alternatives
Your comparison set: Treasury bonds (risk-free at their duration), FDIC-insured CDs (same risk, often higher yield than Treasuries for same term), and high-yield savings accounts (for short horizons). Corporate bonds should yield 0.5–3%+ above comparable Treasuries to compensate for credit risk. Municipal bonds should yield less on a pre-tax basis but more on an after-tax basis for higher-bracket investors.
- 5
Decide: individual bonds or bond funds?
Individual bonds held to maturity eliminate interest rate risk (you know exactly what you'll receive). Bond funds have no maturity date — they hold bonds of varying duration and you can lose principal if rates rise and you sell. Individual bonds require larger minimums ($1,000–$10,000+) and are less liquid. Bond funds offer diversification and daily liquidity. For most retail investors, low-cost bond index funds (like BND or AGG) are more practical than individual bond selection.
Bond Investment Questions
Are I-bonds still a good investment?
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Series I savings bonds are Treasury bonds with interest rates tied to inflation (CPI). They were extremely attractive in 2022 when inflation hit 9.6% composite rates. As inflation has fallen, I-bond rates have moderated to 3–5% range. Advantages: government-guaranteed, inflation-protected, no state income tax. Limitations: $10,000/year purchase limit per person, 1-year lockup, and a 3-month interest penalty if redeemed before 5 years. They remain a solid holding for the emergency fund tier above immediately needed cash.
How do callable bonds work?
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A callable bond gives the issuer the right to redeem the bond before maturity, typically when interest rates fall and they can refinance cheaper. This is bad for investors — you lose a high-coupon bond exactly when rates are falling and reinvestment options are lower-yielding. Callable bonds typically pay a higher coupon to compensate. When evaluating callable bonds, calculate 'yield to call' (as if the issuer calls at the earliest call date) in addition to YTM — whichever is lower is the more conservative return estimate.
What's the difference between buying bonds directly vs. bond ETFs?
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Buying individual bonds directly (through TreasuryDirect for Treasuries, or a broker for corporate/muni bonds) gives you a defined maturity date and face value — you know exactly when you'll be repaid. Bond ETFs (like BND, AGG, TLT) hold many bonds and trade like stocks. ETFs have no maturity date, so you can lose principal if you sell when rates are high. The trade-off: individual bonds require more capital and research; ETFs offer instant diversification and liquidity but with ongoing price risk.
Evaluate Your Bond Investment
YTM, after-tax yield, duration risk, and comparison against alternatives — everything you need to decide if this bond belongs in your portfolio.
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