Updated October 17, 2026. Quick answer: Box 6 of Form 1099-OID shows the acquisition premium amortization for the year on a taxable covered security. It reduces the OID that is included as interest on your return, and it concerns people who bought a discounted obligation for more than its adjusted issue price. When the box is filled in, the form sends you to the Schedule B instructions.
Related reading on this site: IRS Publication 1212.
What box 6 reports
The recipient instructions open with this sentence: “For a taxable covered security, shows the amount of acquisition premium amortization for the year that reduces the amount of OID that is included as interest on your income tax return.”
Box 6 sits beside the OID in Form 1099-OID box 1 (or the Treasury OID in Form 1099-OID box 8). For a description of what a covered security is, the form points elsewhere: “For a description of covered securities, see the Instructions for Form 8949.” The sale-side reporting of covered securities is on the page for Form 8949. The other boxes on the form are in the Form 1099-OID boxes guide.
What acquisition premium is
Publication 550 gives the two-part test: “You bought a debt instrument at an acquisition premium if both the following are true.” “You did not pay a premium.” “The instrument’s adjusted basis immediately after purchase (including purchase at original issue) was greater than its adjusted issue price.”
The publication then states the effect: “Acquisition premium reduces the amount of OID includible in your income. See Pub. 1212 for more information.” In words, if you paid more than the obligation’s adjusted issue price, part of the OID that would otherwise be taxed is offset. Box 6 is the payer’s figure for that offset.
Gross reporting versus net reporting
The payer has a choice, and which one it made decides what you do. The form explains: “For a covered security acquired with acquisition premium, your payer must generally report either (1) a net amount of OID that reflects the offset of OID by the amount of acquisition premium amortization for the year, or (2) a gross amount for both the OID and the acquisition premium amortization for the year.”
The filer instructions tell the payer when to leave the box empty: “If you reported a net amount of OID in box 1, 8, or 11, as applicable, leave this box blank.” From the recipient side, the form says the same thing: “If an amount is not reported in this box for a covered security acquired with acquisition premium, the payer has reported a net amount of OID that reflects the offset of OID that is included in income.”
For a security that is not covered, the rule is different: “For a noncovered security acquired with acquisition premium, your payer is only required to report the gross amount of OID.” The warning that you may have to figure the correct amount yourself is on Form 1099-OID box 1.
An illustration of gross reporting
The numbers below are an illustration, not an IRS example. Suppose a payer reports gross figures with $400 in box 1 and $90 in box 6 (figures chosen only for this illustration). The form says the box 6 amount reduces the OID included in income, so the OID that ends up in interest income would be $310, which is $400 minus $90. If the payer had reported the net amount instead, box 1 would already show $310 and box 6 would be blank.
What to do on Schedule B
When the box is filled in, the form says: “If an amount is reported in this box, see the Instructions for Schedule B (Form 1040).” The Schedule B method for reporting less OID than the form shows is in Publication 550: “include the full amount of OID shown on your Form 1099-OID or other statement on Schedule B (Form 1040), Part I, line 1.” “Identify the amount as” “OID Adjustment” and subtract it from the subtotal. The general page for Schedule B (Form 1040) shows where those lines sit.
If the payer already netted the figure, the form is explicit: “If the payer has reported a net amount of OID in box 1 or box 8, you must report the net amount of OID on Schedule B (Form 1040) and you must not make an adjustment to this amount for acquisition premium on Schedule B (Form 1040).” Taking the box 6 reduction a second time would count the same offset twice.
Tax-exempt obligations
Box 6 can also appear on a tax-exempt obligation: “If there is an amount in both boxes 6 and 11, for a tax-exempt obligation that is a covered security acquired on or after January 1, 2017, and is issued with OID, the amount in box 6 shows the amount of acquisition premium amortization for the year that reduces the amount of your tax-exempt OID for the year.” “The payer may, but is not required to, report the acquisition premium for a tax-exempt obligation that is a covered security acquired before January 1, 2017, and issued with OID.”
A related premium, paid on a bond rather than on a discounted obligation, is reported in box 10 and explained on the page for Form 1099-OID box 10. Form 1099-INT reports the corresponding bond premium; see the Form 1099-INT market discount and bond premium page.
Edition and box numbers
Form 1099-OID has one edition on file for this page. The form is marked “(Rev. January 2024)”, and that is the edition the IRS website served as the current form on October 17, 2026. No other edition is compared here, so there is no difference between editions to report. Publication 550 for 2025 returns is used for where amounts go on the return.
Look at the line that reads “For calendar year” on the copy you received and confirm it shows the tax year you are filing before you rely on any box description on this page. The box numbers above are the numbers printed on the form itself.
Common mistakes
- Adjusting a figure the payer already netted. The form says you “must not make an adjustment to this amount for acquisition premium on Schedule B (Form 1040).”
- Ignoring a filled-in box 6. The form says “If an amount is reported in this box, see the Instructions for Schedule B (Form 1040).”
- Assuming every payer reports the same way. For a noncovered security, “your payer is only required to report the gross amount of OID.”
Related: Schedule B (Form 1040), Form 8949, market discount and bond premium, and Form 1040.
Sources
- Form 1099-OID (Rev. January 2024) with Instructions for Recipient: https://www.irs.gov/pub/irs-pdf/f1099oid.pdf
- Instructions for Forms 1099-INT and 1099-OID (Rev. January 2024): https://www.irs.gov/pub/irs-pdf/i1099int.pdf
- Publication 550, Investment Income and Expenses (for 2025 returns): https://www.irs.gov/pub/irs-pdf/p550.pdf
Read from the IRS documents linked above on October 17, 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.