Updated September 30, 2026. Quick answer: Boxes 10 to 13 of Form 1099-INT cover bonds bought at a discount or a premium. Box 10 is market discount, Box 11 is premium on a taxable bond, Box 12 is premium on a Treasury obligation and Box 13 is premium on a tax-exempt bond.
Form 8949 for 2025, read code by code: Form 8949 code D.
Read box by box from the IRS form text: Form 1099-OID box 6, Form 1099-OID box 10 and Form 1099-DA boxes 1h and 1i.
The IRS form or worksheet behind this, read line by line: Schedule B instructions.
The four boxes
The 1099-INT instructions read here are the January 2024 revision (combined with Form 1099-OID), which is the edition irs.gov shows as current for those forms. Those are instructions to the payer that files the form, so they show what a box is meant to hold, not what tax follows from it. Each row below quotes the instruction for that box.
| Box | IRS heading | What the IRS says the box holds |
|---|---|---|
| 10 | Market Discount | “if the recipient notified you that a section 1278(b) election was made, enter the amount of market discount that accrued on the debt instrument during the tax year in the amount of $10 or more.” |
| 11 | Bond Premium | “For a taxable covered security acquired at a premium (other than a U.S. Treasury obligation), enter the amount of bond premium amortization allocable to the interest paid during the tax year, unless you were notified in writing that the holder did not want to amortize bond premium under section 171.” |
| 12 | Bond Premium on Treasury Obligations | “For a U.S. Treasury obligation that is a covered security, enter the amount of bond premium amortization allocable to the interest paid during the tax year, unless you were notified in writing that the holder did not want to amortize bond premium under section 171.” |
| 13 | Bond Premium on Tax-Exempt Bond | “For a tax-exempt covered security acquired at a premium, enter the amount of bond premium amortization allocable to the interest paid during the tax year.” |
When the premium box stays blank
The instructions tell the payer to leave the premium box blank if it already netted the premium into the interest. For Box 11: “If you are required to report bond premium amortization and you reported a net amount of interest in box 1, leave this box blank.” Box 12 says the same for “a net amount of interest in box 3”, and Box 13 for “a net amount of interest in box 8 or 9, whichever is applicable”.
Box 14: which bond
Box 14 names the bond. The instruction is “For single bonds or accounts containing a single bond, enter the CUSIP number of the tax-exempt bond for which tax-exempt interest is reported in box 8”. The interest boxes themselves are on the Box 1 page.
Common mistakes
- Assuming every bond premium shows in Box 11. A Treasury premium is in Box 12 and a tax-exempt premium in Box 13.
- Expecting all four boxes filled in. A payer that netted the premium into the interest leaves the premium box blank.
- Adding the premium to the interest in Box 1. The instructions treat it as a separate amount.
Related: 1099-INT Box 3: Savings Bond and Treasury Interest, and 1099-INT Box 8 and 9: Tax-Exempt Interest on Municipal Bonds.
Every box in one place: the 1099-DIV, 1099-INT and 1099-B boxes table. If your withdrawal came from an IRA or 401(k), see the Form 1099-R Box 7 codes.
Sources
- IRS, Instructions for Form 1099-DIV (Rev. January 2024): irs.gov/pub/irs-pdf/i1099div.pdf
- IRS, Instructions for Forms 1099-INT and 1099-OID (Rev. January 2024): irs.gov/pub/irs-pdf/i1099int.pdf
- IRS, Instructions for Form 1099-B (2026): irs.gov/instructions/i1099b
Source: the IRS instructions for the filer of each form, read at irs.gov on September 30, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer, the account provider or the IRS is the right place to confirm anything consequential.