To amend Form 1065, first check whether the original filing deadline (including extensions) has passed. If it hasn’t, file a superseding return that replaces the original. If it has, the correction is either an amended return (for partnerships that elected out of the Bipartisan Budget Act centralized audit regime, or for tax years before 2018) or an Administrative Adjustment Request (for BBA partnerships). Which path applies determines the forms you file, who has authority to sign, and who ultimately pays any additional tax.
Try a Superseding Return First
A superseding return is a complete replacement filed before the extended due date. The IRS treats it as the original return for every purpose, including tax elections that must be made on a timely filed original.1Taxpayer Advocate Service. What to Know About Superseding Tax Returns and How It Could Benefit You That matters because many partnership elections become irrevocable once the deadline passes. An amended return filed later cannot revive them.
To supersede electronically, file a complete corrected Form 1065 with the superseding designation selected in your tax software. On paper, there is no separate checkbox; you simply file the complete replacement Form 1065 before the extended due date.2Internal Revenue Service. Amended and Superseding Corporate Returns
If the deadline has already passed, superseding is off the table and you move to a formal amendment.
BBA or Non-BBA: The Fork That Drives Everything
The BBA centralized audit regime applies to every partnership for tax years beginning after December 31, 2017, unless the partnership validly elected out.3Internal Revenue Service. BBA Centralized Partnership Audit Regime
A partnership can elect out only if it had 100 or fewer partners during the tax year and every partner was an eligible partner throughout that year. Eligible partners include individuals, C corporations, foreign entities that would be C corporations if domestic, S corporations, and estates of deceased partners.4Internal Revenue Service. Elect Out of the Centralized Partnership Audit Regime Trusts and other partnerships are not eligible. A single trust partner disqualifies the partnership from electing out.
If the partnership elected out, or if the year predates 2018, follow the non-BBA amended return process. If BBA applies, file an Administrative Adjustment Request.
Amending a Non-BBA Partnership Return
Electronic Filing
Prepare a complete corrected Form 1065 with all schedules and attachments, check the “Amended Return” box, and attach an Amended Return Statement explaining every change. Include corrected Schedules K-1 for every affected partner.5Internal Revenue Service. Guidance for Amended Partnership Returns The return must be complete, not just the changed lines. Any form or schedule that changed, or that supports a change, has to be in the submission.
Paper Filing With Form 1065-X
Partnerships that don’t e-file use Form 1065-X, which shows original amounts, the net change per line, and the corrected amounts side by side.6Internal Revenue Service. About Form 1065-X, Amended Return or Administrative Adjustment Request (AAR) Complete only the lines that actually change. An increase in expenses is a negative adjustment to income; an increase in revenue is a positive adjustment. Those changes flow to ordinary business income and then to each partner’s distributive share.
Part III of Form 1065-X requires a detailed explanation of every change. Vague descriptions invite IRS correspondence and slow the return down. If the correction touches a tax election, reference the code section and the date of the original election. Attach revised depreciation schedules, corrected vendor records, and any other documentation that supports the numbers.
Mail the signed Form 1065-X, all attachments, and corrected Schedules K-1 for every affected partner to the service center where the original return was filed. The address depends on the partnership’s principal place of business. Certified mail with return receipt establishes a clear filing date. Missing K-1s will get the submission rejected or stalled.
Filing an AAR for a BBA Partnership
Under the BBA, only the Partnership Representative has authority to file an AAR, and the PR’s decisions bind every partner. The PR also decides whether the partnership pays the resulting tax at the entity level or pushes the adjustments out to the partners who were in the partnership during the reviewed year.
Electronic Filing
File a corrected Form 1065 with box G(5) (“Amended return”) checked, together with Form 8082, Notice of Inconsistent Treatment or Administrative Adjustment Request.7Internal Revenue Service. File an Administrative Adjustment Request for a BBA Partnership If the partnership is making a push-out election, or if the AAR contains adjustments that don’t produce an imputed underpayment, also include Form 8985 (the pass-through statement transmittal) and Forms 8986 (each partner’s share of the adjustments).
Paper Filing
On paper, the PR files Form 1065-X in place of the Form 1065 plus Form 8082 combination used for e-filing.7Internal Revenue Service. File an Administrative Adjustment Request for a BBA Partnership Forms 8985 and 8986 still apply when the partnership is pushing out adjustments.
Who Pays: Imputed Underpayment vs. Push-Out
When a BBA partnership’s AAR increases the aggregate tax liability, the default is that the partnership itself pays an imputed underpayment at the entity level. This is the biggest conceptual difference from the old rules: tax is collected from the partnership, not from the individual partners of the reviewed year.
The imputed underpayment is calculated by netting all adjustments for the reviewed year and multiplying the net positive adjustment by the highest rate then in effect under IRC Section 1 (for individuals) or Section 11 (for corporations).8Office of the Law Revision Counsel. 26 USC 6225 – Partnership Adjustment by Secretary For most partnerships that means the 37 percent individual rate is applied to the whole adjustment, regardless of any partner’s actual bracket. The partnership can request modification of the imputed underpayment to reflect lower rates on specific income types (such as capital gains), tax-exempt partners’ shares, or amended returns already filed by partners.
If the partnership pays the imputed underpayment, partners generally do not amend their personal returns for the reviewed year. The payment is treated as a non-deductible expenditure that reduces partners’ capital accounts.
The Push-Out Election
Instead of paying at the entity level, the partnership can elect to push the adjustments out to the reviewed-year partners. The election is made when the AAR is filed and is irrevocable. Include Form 8985 and Forms 8986 with the AAR.7Internal Revenue Service. File an Administrative Adjustment Request for a BBA Partnership Each reviewed-year partner then reports the adjustment on their return for the adjustment year (the year the AAR was filed), not by amending the reviewed year. Interest and penalties travel with the partners.
Push-out often makes sense when partners have lower effective rates than the 37 percent applied to the imputed underpayment, or when tax-exempt partners hold a large share of the partnership. Compare the entity-level imputed underpayment plus interest against what the partners would owe at their own rates.
Interest on the Imputed Underpayment
Interest on an imputed underpayment runs from the day after the due date of the partnership return for the reviewed year until the earlier of the payment date or the due date of the return for the adjustment year.9eCFR. 26 CFR 301.6233(a)-1 – Interest and Penalties Determined From Imputed Underpayment On a two- or three-year-old return, that interest builds quickly, and it is part of the entity-vs.-push-out math.
Deadline to File the Correction
A partnership can file an amended return or AAR within three years of the later of: the date the partnership return was actually filed, or the last day for filing that return, not counting extensions.10eCFR. 26 CFR 301.6227-1 – Administrative Adjustment Request by Partnership A 2024 return filed February 15, 2025 with a March 15, 2025 due date starts the clock on March 15, 2025 and stays open until March 15, 2028. A return filed early never starts the clock before the due date.
Once the IRS mails a Notice of Administrative Proceeding for a particular tax year, the partnership can no longer file an AAR for that year. There is no advance warning, so if you know a correction is needed, file it.
Corrected K-1s and Partner Notification
Any amendment or AAR that changes information on a partner’s Schedule K-1 requires the partnership to furnish a corrected K-1 to every affected partner, clearly marked as “Amended” or “Corrected.”11Office of the Law Revision Counsel. 26 USC 6031 – Return of Partnership Income
For non-BBA partnerships, and for BBA partnerships that made the push-out election, partners generally need to file amended individual returns or report the adjustments on their current-year return, depending on which regime and method applied. Under IRC Section 6222, partners must treat partnership-related items consistently with the partnership’s return; an underpayment from inconsistent treatment is assessed as a math error, with no deficiency notice and no Tax Court petition before payment.12Office of the Law Revision Counsel. 26 USC 6222 – Partner’s Return Must Be Consistent With Partnership Return Get corrected K-1s to partners promptly so they can meet their own obligations.
State Filings
Most states require partnerships to report federal changes within a set timeframe, often 60 to 180 days after the federal amendment is finalized. Some states want a separate amended state partnership return; others accept the federal amendment with a cover letter. Check the state requirement right after filing the federal correction, because state deadlines carry their own penalties.
Penalties and Interest
An amendment that increases reported income can expose the partnership (under BBA) or the partners (non-BBA and push-out) to accuracy-related penalties. The standard rate is 20 percent of the underpayment attributable to negligence or substantial understatement, doubling to 40 percent for a gross valuation misstatement. Reasonable cause and good faith are a defense, and voluntary self-correction generally reads better than a correction the IRS finds first, but filing an amendment does not automatically waive penalties.
For BBA partnerships paying the imputed underpayment, interest begins accruing the day after the due date of the original return for the reviewed year.9eCFR. 26 CFR 301.6233(a)-1 – Interest and Penalties Determined From Imputed Underpayment
A Common Trigger: The Missed Section 754 Election
A frequent reason to amend is a missed Section 754 election, which lets the partnership adjust the basis of its property after a transfer of an interest or a distribution. If fewer than 12 months have passed since the original due date (including extensions), the partnership gets automatic relief under Treasury Regulation Section 301.9100-2, with no IRS approval needed. Past 12 months, the partnership must request discretionary relief under Section 301.9100-3, which requires showing that it acted reasonably and in good faith and depends on Commissioner approval.13Internal Revenue Service. FAQs for Internal Revenue Code (IRC) Sec. 754 Election and Revocation Either way, the partnership still files an amended or superseding return that includes the election statement.
Capital Accounts and Basis
Every income or expense change ripples into partner capital accounts. An increase in ordinary income raises capital accounts; a non-deductible expense reduces them without changing taxable income; a correction to tax-exempt income raises capital accounts without changing the reported taxable amount.
When the original error involved an incorrect basis in partnership property, the amendment has to correct the property’s basis going forward too, which affects future depreciation and the eventual gain or loss on sale. If any balance sheet figure changes, attach a revised Schedule L. The income correction usually gets the attention; the capital account and basis follow-through is where amended partnership returns tend to go wrong.