Bond premium is not taxable income. If you paid more than face value for a bond, that extra amount is a cost you recover over the bond’s life, not something you owe tax on. For taxable bonds, you can elect to amortize the premium under IRC Section 171 and reduce the interest income you report each year. For tax-exempt bonds like municipals, amortization is mandatory, but since the interest was never taxed, the only effect is a gradual reduction in your cost basis.1Office of the Law Revision Counsel. 26 USC 171 – Amortizable Bond Premium
Taxable Bonds: Premium Offsets Interest, Not a Separate Deduction
When you elect to amortize premium on a taxable bond, the amortized portion each year directly reduces the interest you report. If a bond pays you $1,000 in interest and $150 of premium amortizes that year, you report $850 as taxable interest. There is no separate deduction line; the premium shrinks the interest figure itself.
The same amount comes off your adjusted cost basis in the bond. That basis reduction is the other half of the mechanism, and it matters because you will only get face value back at maturity. Without the annual adjustment, you would be sitting on an artificial capital loss when the bond matured. Amortization brings your basis down to par over the life of the bond so no phantom loss appears at the end.2Office of the Law Revision Counsel. 26 USC 1016 – Adjustments to Basis
Sell before maturity and your adjusted basis at that moment sets your gain or loss. The premium you already used against interest is gone from the tax picture. You recovered it through smaller interest reports along the way, not through a loss at sale.
Making the Section 171 Election
Amortization on taxable bonds is not automatic. You elect it by reporting the amortization on your return for the first year you want it to apply and attaching a statement that you are electing under Section 171.3Internal Revenue Service. Publication 550 – Investment Income and Expenses
The election is all or nothing. Once made, it covers every taxable bond you hold at that time and every taxable bond you buy later. You cannot pick which bonds get the treatment. Reversing the election requires written IRS approval and a Form 3115, Application for Change in Accounting Method.4eCFR. 26 CFR 1.171-4 – Election to Amortize Bond Premium on Taxable Bonds
Most investors holding premium bonds do better with the election than without it. Reducing taxable interest each year is almost always preferable to carrying an unrealized loss until maturity. The scope is the thing to think through before electing, especially if your holdings are a mix of premium and discount bonds.
Tax-Exempt Bonds: Required Basis Reduction, No Income Effect
Municipal bonds and other tax-exempt bonds follow a different rule. Amortization is mandatory, no election involved. But because the interest is already excluded from gross income, the amortized premium has nothing to offset. Its only job is reducing your cost basis each year.
The reason becomes obvious with numbers. Suppose you pay $11,000 for a $10,000 municipal bond with ten years to maturity. At maturity, you get $10,000 back. Without mandatory basis reduction, you would claim a $1,000 capital loss, turning a premium you willingly paid for tax-free income into a deduction. Required amortization pulls your basis from $11,000 down toward $10,000 over the holding period, so maturity produces no gain or loss.2Office of the Law Revision Counsel. 26 USC 1016 – Adjustments to Basis
Sell before maturity and your basis is the original cost minus the cumulative amortization through that date. That figure determines any capital gain or loss on the sale. The record-keeping sits on you if the broker does not do it, since no annual income entry forces the issue.
One wrinkle: certain private activity municipal bonds pay interest exempt from regular federal income tax but still subject to the alternative minimum tax. The official statement for the bond issue will flag this. The premium amortization rules themselves do not change for these bonds; the AMT treatment of the interest is a separate matter.
Reporting Bond Premium on Your Return
How you handle premium at filing time depends on what your brokerage reports and which type of bond you hold.
What the 1099-INT Boxes Mean
Form 1099-INT has several boxes tied to bond premium. Box 1 is taxable interest. Box 11 shows amortizable premium on taxable covered securities other than Treasuries. Box 12 is premium on Treasury obligations. Box 13 is premium on tax-exempt bonds.5Internal Revenue Service. Form 1099-INT
Brokers have a choice in how they present this. Some report gross interest in Box 1 and the premium separately in Box 11. Others report a net interest figure in Box 1 that already reflects the premium offset and leave Box 11 blank. If Box 11 is empty on a covered premium bond, check whether Box 1 is already the reduced figure. The 1099-INT instructions explain which approach your broker used.6Internal Revenue Service. Instructions for Forms 1099-INT and 1099-OID
The ABP Adjustment on Schedule B
If your broker reported gross interest in Box 1, you make the adjustment yourself on Schedule B. List the gross interest, then below the subtotal subtract the amortized premium and label the entry “ABP Adjustment.” The net flows through as your taxable interest.7Internal Revenue Service. Instructions for Schedule B (Form 1040)
If Box 1 already shows a net amount, do not subtract anything further on Schedule B. The adjustment is already in the number. Doubling it is a common mistake.
Cost Basis When You Sell
When you sell, your broker reports adjusted cost basis in Box 1e of Form 1099-B for covered securities. For covered bonds, the broker is required to account for amortized premium in that figure, so the basis should already reflect the annual reductions. For noncovered securities, generally those acquired before certain dates, Box 1e may be blank, and you are responsible for tracking the adjusted basis yourself.8Internal Revenue Service. Instructions for Form 1099-B
Keeping Records on Tax-Exempt Bonds
Tax-exempt bonds generate lighter reporting during the holding period, since the interest never appears on Schedule B. But the mandatory basis reduction still demands a running tally. You need an adjusted basis figure reduced each year by the amortized premium so you can report gain or loss accurately when the bond matures or you sell. Getting this wrong usually means overstating a loss or understating a gain, and both draw IRS attention.
When Amortized Premium Exceeds the Interest Payment
Late in a bond’s life, or when a bond was bought at a steep premium, the amortized premium for a period can exceed the interest paid that period. The tax result depends on the bond type.
For taxable bonds, the excess is deductible as a loss, but only up to the total net interest you have previously included from that bond minus the total premium already deducted. Anything beyond that carries forward to the next period. The deduction is not subject to the 2% floor on miscellaneous itemized deductions.9eCFR. 26 CFR 1.171-2 – Amortization of Bond Premium
For tax-exempt bonds, the excess is a nondeductible loss. It cannot offset any income, and it does not carry forward in any usable way. Basis still steps down, but the excess beyond the interest produces no tax benefit.