Bond interest is the periodic payment you receive for lending money to a bond issuer, and how it is calculated, taxed, and paid comes down to three fixed inputs and one variable one. The calculation is par value multiplied by the coupon rate. The payment arrives on the schedule written into the bond at issuance, most often twice a year. The tax depends on who issued the bond: corporate interest is ordinary income, Treasury interest is federally taxable but exempt from state tax, and most municipal interest is exempt from federal tax. A $1,000 bond with a 5% coupon pays $50 a year no matter what the bond trades for; what you keep after tax is where the rules get interesting.
How the Interest Amount Is Calculated
Two numbers determine every interest payment: par value and coupon rate. Par value, also called face value, is the amount the issuer promises to repay at maturity, and for most corporate bonds that number is $1,000, though some issues use $100 or other denominations.1Legal Information Institute. Par Value The coupon rate is the fixed annual percentage the issuer commits to pay, locked in when the bond is first sold.
Multiply the two and you get the annual interest. A $1,000 bond with a 6% coupon pays $60 per year. If that same bond later trades at $1,100 or $850 on the secondary market, the coupon payment does not change. Issuers always calculate interest off the original face value, which is what makes the cash flow predictable for anyone holding to maturity.
When and How Payments Arrive
Most U.S. Treasury notes and bonds pay interest semiannually, in two equal installments six months apart.2eCFR. 31 CFR 356.30 – Payments Corporate bonds typically follow the same convention. So a bond with a $60 annual coupon delivers $30 in June and $30 in December.
Other schedules exist. Some bonds pay annually or quarterly, and certain mortgage-backed securities distribute interest monthly. Zero-coupon bonds pay nothing along the way and settle in a single payment at maturity.
Payment Structures That Change the Cash Flow
The structure built into a bond at issuance determines whether your payments stay flat, move with the market, or arrive only at the end.
Fixed-Rate Bonds
The most common structure locks in one coupon rate for the life of the bond. A fixed-rate bond paying 4.5% on a $1,000 face value delivers $45 per year from purchase to maturity regardless of what happens to market interest rates. This is why fixed-rate bonds appeal to investors who want steady income they can plan around.
Floating-Rate Bonds
Floating-rate bonds adjust their interest payments periodically against an external benchmark. Many are tied to the Secured Overnight Financing Rate (SOFR), which measures the cost of overnight borrowing collateralized by Treasury securities.3Federal Reserve Bank of New York. Secured Overnight Financing Rate (SOFR) A typical floater might pay SOFR plus a fixed spread of 50 basis points.4World Bank. World Bank Prices USD 1.75 Billion SOFR Index-Linked Floating Rate Bond When market rates rise your payments rise; when they fall your payments shrink.
Zero-Coupon Bonds
Zero-coupon bonds skip periodic interest entirely. You buy at a deep discount and receive the full face value at maturity. A 20-year zero with a $10,000 face value might sell for $3,500 today, and the $6,500 difference is your return.5FINRA. Zero-Coupon Bonds No checks arrive in the mail along the way, but the tax treatment (covered below) is not as clean as the cash flow.
Inflation-Protected Bonds (TIPS)
Treasury Inflation-Protected Securities pay a fixed coupon rate, but the principal adjusts up or down with the Consumer Price Index. Because interest is calculated on the adjusted principal, dollar payments rise during inflation and fall during deflation.6TreasuryDirect. Treasury Inflation-Protected Securities (TIPS) Buy a TIPS with a $1,000 par value and 1.5% coupon, and if inflation pushes the adjusted principal to $1,030, your semiannual interest is calculated on $1,030 rather than the original $1,000.
Step-Up Bonds
Step-up bonds start with a lower coupon rate that increases on a set schedule. A 10-year step-up might begin at 3% and rise by half a percentage point each year that the issuer does not call the bond. Most step-ups are callable, meaning the issuer can redeem the bond early rather than pay the higher rate, and the rising coupon compensates you for that call risk.
How the Interest Is Taxed
Tax treatment depends almost entirely on who issued the bond. The differences are large enough to change which bond type belongs in a taxable account.
Corporate Bonds
Interest from corporate bonds is ordinary income. Federal tax law includes interest of all kinds in gross income, and corporate bond interest receives no special exemption.7Office of the Law Revision Counsel. 26 USC 61 – Gross Income Defined You owe federal income tax at your marginal rate, and most states tax it as well.
U.S. Treasury Bonds
Treasury interest is taxable at the federal level but exempt from state and local income taxes by statute.8Office of the Law Revision Counsel. 31 USC 3124 – Exemption From Taxation For investors in high-tax states, that state-level exemption can meaningfully lift after-tax returns compared with a corporate bond of similar pre-tax yield.
Municipal Bonds
Interest on bonds issued by state and local governments is generally exempt from federal income tax.9Office of the Law Revision Counsel. 26 USC 103 – Interest on State and Local Bonds If you live in the state that issued the bond, the interest is often exempt from state tax too. Buy an out-of-state municipal bond and your state will usually tax the interest.
One wrinkle. Interest on certain private activity bonds is treated as a preference item for the Alternative Minimum Tax. Bonds financing airports, housing, or industrial development through private entities can trigger AMT liability, though 501(c)(3) bonds and certain housing bonds are excluded.10Office of the Law Revision Counsel. 26 USC 57 – Items of Tax Preference Most individual investors never hit the AMT, but the exposure is worth checking if you hold a large position in private activity munis.
Form 1099-INT Reporting
Financial institutions file Form 1099-INT for any person who earned $10 or more in interest during the year. Box 1 reports taxable interest from corporate bonds and Treasuries, and Box 8 reports tax-exempt interest from municipal bonds.11Internal Revenue Service. Instructions for Forms 1099-INT and 1099-OID Tax-exempt interest still goes on your return; it just does not increase your regular income tax.
When the Price You Paid Changes the Tax Bill
Buying a bond above or below face value creates tax consequences that go beyond the coupon. These rules catch investors who focus only on the interest check and forget about the price they paid.
Phantom Income on Zero-Coupon Bonds
Zeros pay no cash until maturity, but the IRS still treats you as earning a slice of the discount every year. Federal law requires you to include in gross income the daily portions of original issue discount for each day you hold the bond during the tax year.12Office of the Law Revision Counsel. 26 USC 1272 – Current Inclusion in Income of Original Issue Discount This is often called phantom income because you owe tax on money you have not received.5FINRA. Zero-Coupon Bonds Holding zeros in a taxable account means an annual tax bill with no corresponding cash to pay it, which is why many investors keep them inside IRAs.
Market Discount Bonds
When you buy a bond on the secondary market for less than its face value, the gap between purchase price and par is called market discount. If you later sell at a gain or receive par at maturity, the gain is treated as ordinary income (not capital gains) to the extent it does not exceed the accrued market discount.13Office of the Law Revision Counsel. 26 USC 1276 – Disposition Gain Representing Accrued Market Discount Treated as Ordinary Income For most people, that is a worse rate than capital gains.
A de minimis exception applies. If the discount is less than one-quarter of one percent of the face value multiplied by the number of full years remaining to maturity, the discount is treated as zero and any gain is taxed at capital gains rates.14Office of the Law Revision Counsel. 26 USC 1278 – Definitions and Special Rules – Market Discount on Bonds For a bond with 10 years to maturity and a $1,000 face value, the cutoff is $25. Buy it for $976 and the discount is de minimis; buy it for $970 and you are in ordinary-income territory.
Bonds Purchased at a Premium
If you buy a taxable bond above its face value, the excess is bond premium. You can elect to amortize that premium over the remaining life of the bond, reducing the amount of interest you report as taxable each year.15Office of the Law Revision Counsel. 26 USC 171 – Amortizable Bond Premium Without the election, you pay tax on the full coupon even though part of each payment is really returning the extra price you paid. For tax-exempt municipals, premium amortization is required but produces no deduction because the interest is not taxed to begin with.
Accrued Interest on Purchases and Sales
When a bond changes hands between coupon dates, the buyer pays the seller for the interest that has built up since the last payment. This amount is called accrued interest, and it compensates the seller for holding the bond during a period when no coupon was distributed.16FINRA. Accrued Interest Calculator
The math divides the annual coupon by the number of days in the period and multiplies by the days the seller held the bond since the last payment date. A bond paying $60 per year sold exactly halfway through a semiannual period generates about $15 of accrued interest for the seller. When the next full $30 coupon lands, the buyer collects it and is effectively made whole. Day-count conventions differ by security type (corporate and municipal bonds typically assume 30/360 while Treasuries count actual days), which is why accrued interest figures can vary slightly between securities.
Risks That Can Reduce What You Keep
The coupon rate is fixed, but several forces can erode the real value of your payments or cut them off entirely.
Interest Rate Risk
When market interest rates rise, prices of existing fixed-rate bonds fall, because new bonds offer higher coupons and older ones look less attractive.17U.S. Securities and Exchange Commission. When Interest Rates Go Up, Prices of Fixed-Rate Bonds Fall Hold to maturity and you still collect every coupon and your full principal. Sell early and you take the loss. Longer-term bonds swing more than shorter ones for the same rate move.
Inflation Risk
A fixed $50 coupon buys less over time when consumer prices rise faster than your yield. A 3% bond in a 4% inflation environment produces a negative real return. This is the core vulnerability of fixed-rate bonds, and it is why TIPS and floating-rate bonds exist.
Credit and Default Risk
An issuer in financial trouble may miss interest payments or default outright. In a corporate bankruptcy, bondholders typically rank as general unsecured creditors unless the bond is backed by specific collateral, which places them behind priority claims like employee wages and certain tax obligations.18Office of the Law Revision Counsel. 11 USC 507 – Priorities Lower-rated bonds pay higher coupons precisely because the market thinks there is a real chance of not getting paid in full.
Call Risk
Many corporate and municipal bonds include call provisions that let the issuer redeem the bond before maturity, usually after a specified no-call period. Issuers tend to call when market rates fall below the bond’s coupon rate, because they can refinance at a lower cost.19Investor.gov. Callable or Redeemable Bonds When your bond gets called, the interest payments stop, you receive the call price, and you are left to reinvest at whatever lower rate the market now offers. Callable bonds carry slightly higher coupons than comparable non-callable bonds to compensate.