Form 1065-X is the IRS form partnerships use to fix mistakes on their tax returns or request administrative adjustments. If your partnership filed Form 1065 (U.S. Return of Partnership Income), Form 1065-B (for electing large partnerships), or Form 1066 (for real estate mortgage investment conduits or REMICs) for the 2013 tax year and later discovered errors, Form 1065-X is your tool for making corrections. Think of it as the partnership equivalent of Form 1040-X that individual taxpayers use to amend their personal returns.

What Form 1065-X Is For

Form 1065-X serves two primary purposes for partnerships that filed 2013 returns. First, it allows partnerships to file an amended return to correct errors in previously filed partnership tax returns. These errors might include incorrect income totals, overstated or missed deductions, wrong credits, or mistakes in partner capital accounts. Second, it enables partnerships to file an Administrative Adjustment Request (AAR), which is a special procedure used by certain partnerships subject to unified audit procedures under TEFRA (Tax Equity and Fiscal Responsibility Act) rules that applied during the 2013 tax year.

The form essentially has three columns: Column (a) shows the original amounts from your 2013 return as filed, Column (b) shows the net increase or decrease for each changed line item, and Column (c) displays the correct amounts. This side-by-side comparison format makes it easy for the IRS to see exactly what changed and why.

Unlike individual amended returns, partnership corrections affect not only the partnership entity but also flow through to all partners, who may need to amend their individual returns based on corrected Schedule K-1 forms showing their revised share of partnership income, deductions, and credits.

When You’d Use Form 1065-X (Late/Amended Filing)

Common Reasons to File

You would use Form 1065-X when you discover errors in your 2013 partnership return after you've already filed it. Common scenarios include discovering additional income that wasn't reported, finding legitimate deductions that were overlooked, correcting mathematical errors in calculating partner distributions, fixing errors in depreciation calculations, or adjusting capital account balances.

Statute of Limitations (Timing)

For 2013 returns, partnerships generally had three years from the later of: (1) the date the partnership return was filed, or (2) the last day for filing the return (excluding extensions) to file an amended return or AAR. For a calendar-year partnership with a 2013 tax year, the original return was due April 15, 2014 (or September 15, 2014, with extensions). This means the deadline to amend that 2013 return would typically have been April 15, 2017, or September 15, 2017, if an extension was filed. However, if you received an IRS notice of audit or adjustment before that deadline, different timing rules may apply.

Paper Filing Only for 2013

It's important to note that Form 1065-X cannot be e-filed for 2013 tax years—it must be submitted on paper and mailed to the same IRS service center where the original return was filed. This differs from more recent tax years where electronic filing options became available for some partnerships.

Key Rules or Details for 2013

Small Partnership Exception (Non-TEFRA)

If your partnership had 10 or fewer partners during 2013, and all partners were either U.S. individuals (not nonresident aliens), their estates, or C corporations, your partnership qualified for the "small partnership exception" and was not subject to TEFRA unified audit procedures. For partnerships meeting this exception, Form 1065-X was used simply as an amended return. Each partner would then file their own amended individual return (Form 1040-X) reflecting the corrected Schedule K-1 information.

TEFRA Partnerships (AAR)

If your partnership had more than 10 partners, or if any partner was a trust, S corporation, another partnership, LLC filing as a partnership, nominee, or nonresident alien, your partnership was subject to TEFRA procedures. Under TEFRA, the partnership's Tax Matters Partner (TMP)—typically a general partner designated on the original return—had the authority to file Form 1065-X as an Administrative Adjustment Request (AAR) on behalf of all partners. The TMP was required to sign the form, and the changes would be handled through centralized partnership-level proceedings rather than partner-by-partner adjustments.

Signature Requirements

For non-TEFRA partnerships in 2013, any partner or LLC member could sign Form 1065-X. For TEFRA partnerships, only the designated Tax Matters Partner could sign. The return wasn't considered valid unless properly signed.

Where to File

Form 1065-X for 2013 had to be mailed to the same IRS service center where the original 2013 Form 1065 was filed—no electronic filing was available for this tax year's amended returns.

Step-by-Step (High Level)

Step 1: Gather Your Original Documents

Collect your original 2013 Form 1065, all schedules including Schedule K (partners' distributive shares), all original Schedules K-1 issued to partners, and any supporting documentation for the changes you're making.

Step 2: Identify What Needs Correction

Carefully review the return and pinpoint exactly what information was incorrect. Document the reasons for each change you're making—the IRS may request detailed explanations.

Step 3: Determine Your Partnership Type

Figure out whether your partnership qualified for the small partnership exception (10 or fewer eligible partners) or was subject to TEFRA procedures. This determines whether you're filing an amended return or an AAR, and who must sign the form.

Step 4: Complete Form 1065-X

Fill out the identification information at the top, then complete Part I by checking the appropriate boxes indicating whether your partnership is subject to TEFRA and whether you're filing an amended return or AAR. In Part II, use the three-column format: enter original amounts in Column (a), calculate the net increase or decrease in Column (b) using positive numbers for increases and parentheses for decreases, and show correct amounts in Column (c).

Step 5: Prepare Amended Schedules K-1

Create corrected Schedule K-1 forms for each partner showing their revised distributive share of income, deductions, and credits. Clearly mark these "AMENDED" and include explanations of what changed.

Step 6: Add Explanations in Part V

Use Part V (Explanations) to provide detailed descriptions of each change you're making and the reasons behind them. Reference specific line numbers and attach supporting documentation.

Step 7: Obtain Proper Signature

Have the form signed by an authorized person—any partner for non-TEFRA partnerships, or the Tax Matters Partner for TEFRA partnerships.

Step 8: Mail to Correct Service Center

Make copies for your records, then mail the complete package (Form 1065-X, amended Schedules K-1, explanations, and supporting documents) to the IRS service center where your original 2013 return was filed.

Step 9: Distribute Amended K-1s

Provide each partner with their amended Schedule K-1 so they can file their own amended individual returns if necessary.

Common Mistakes and How to Avoid Them

Mistake #1: Failing to Use the Correct Form Revision

For 2013 tax years, you must use the September 2018 revision of Form 1065-X or earlier versions appropriate for 2013. Using a form revision designed for later tax years with different rules can cause processing delays or rejections. Solution: Download the correct historical form version from IRS.gov/pub/irs-prior.

Mistake #2: Not Determining TEFRA Status Correctly

Many partnerships incorrectly assume they're small partnerships when they actually have more than 10 partners (counting each spouse separately unless filing jointly) or have ineligible partner types like trusts or S corporations. Solution: Carefully count all partners at all times during 2013 and verify each partner's entity type. Remember that a husband and wife with separate partnership interests count as two partners, not one.

Mistake #3: Wrong Person Signing the Form

A common error is having a regular partner sign Form 1065-X when the partnership was subject to TEFRA and only the designated Tax Matters Partner had authority to sign. Solution: Review your original 2013 Form 1065 to identify who was designated as TMP, and ensure that person signs the amended return.

Mistake #4: Incomplete Column (b) Calculations

Partnerships often forget to show increases and decreases correctly—increases should be positive numbers, decreases should be in parentheses. Mixing these up reverses the intended correction. Solution: Double-check your math. Column (c) should always equal Column (a) plus Column (b) when accounting for positive and negative signs.

Mistake #5: Not Preparing Amended K-1s

Some partnerships file Form 1065-X but forget to prepare and distribute amended Schedule K-1 forms to their partners, leaving partners unaware they need to amend their own returns. Solution: Prepare corrected K-1s for all partners, clearly mark them "AMENDED," and provide them promptly with explanations of changes.

Mistake #6: Insufficient Explanation in Part V

Simply stating "correction" or "error" without explaining what was wrong and why doesn't give the IRS enough information to process your amendment. Solution: Provide detailed, specific explanations for each change, referencing line numbers and including supporting documentation like corrected depreciation schedules or amended 1099 forms.

Mistake #7: Missing the Statute of Limitations

Waiting too long to file your amendment means missing the three-year window, and the IRS won't accept corrections filed after the statute expires. Solution: If you discover errors, act quickly. Don't wait until year three approaches—file as soon as you identify and document the necessary corrections.

What Happens After You File

Processing Timeline

After mailing Form 1065-X for your 2013 return, expect significant processing time—typically 16 to 20 weeks or longer for paper-filed amendments. The IRS receives your return at the service center and assigns it for review.

IRS Review Process

An IRS examiner reviews your Form 1065-X to verify the corrections make sense and are properly documented. They may compare the amended return to the original and check for mathematical accuracy and completeness. If your explanations are clear and your documentation is thorough, processing goes more smoothly.

Three Possible Outcomes

• Accepted as Filed: The IRS accepts your corrections without further questions. For non-TEFRA partnerships, partners simply file their amended individual returns based on the corrected K-1s. For TEFRA partnerships filing an AAR, the IRS may issue a notice of final partnership administrative adjustment reflecting the changes.
• IRS Requests More Information: You receive a letter asking for additional documentation or clarification. Respond promptly and completely to avoid delays or denial of your requested changes.
• Examination/Audit: The IRS selects your amended return for examination, which may expand to other issues beyond your requested corrections. This is more common when amendments significantly reduce partnership income or increase losses.

Partner-Level Impact

Once your Form 1065-X is processed, partners need to amend their individual returns if their distributive shares changed. Partners file Form 1040-X for the 2013 tax year with the corrected Schedule K-1 information. If corrections result in partners owing additional tax, interest will be charged from the original due date of their 2013 returns.

Interest and Penalties

If your amendment shows the partnership should have reported more income (resulting in partners owing more tax), the IRS charges interest from the original due date forward. Late payment penalties may also apply. Conversely, if your amendment results in partners being entitled to refunds, the IRS pays interest on those refunds from the date of overpayment.

No Formal Acknowledgment

Unlike individual amended returns which generate a "received" status you can track online, partnership amended returns generally don't produce trackable status updates. You may not hear anything unless the IRS has questions or completes processing and sends a notice.

FAQs

Q1: Can I e-file Form 1065-X for my 2013 tax year?

No. For 2013 tax years, Form 1065-X must be filed on paper and mailed to the IRS service center where your original return was filed. Electronic filing options for partnership amended returns weren't available for returns from this period.

Q2: If I file Form 1065-X, do my partners automatically get amended K-1s?

No. The partnership is responsible for preparing and distributing amended Schedule K-1 forms to all partners. The IRS doesn't automatically send these to partners. You must create corrected K-1s clearly marked "AMENDED" and provide them to partners so they know to file their own amended individual returns.

Q3: What's the difference between an amended return and an AAR for 2013?

The difference depends on your partnership's TEFRA status. Partnerships qualifying for the small partnership exception (10 or fewer eligible partners) file an "amended return" which simply corrects the original filing. Larger partnerships subject to TEFRA file an "Administrative Adjustment Request (AAR)" which triggers partnership-level unified procedures where the Tax Matters Partner acts on behalf of all partners.

Q4: My partnership had exactly 10 partners—are we subject to TEFRA or not?

You're not subject to TEFRA if you had 10 or fewer partners and all partners were U.S. individuals, their estates, or C corporations. "10 or fewer" includes exactly 10. However, if even one partner was a trust, nonresident alien, or another partnership, you're subject to TEFRA regardless of the total partner count.

Q5: Do I need to attach a copy of the original 2013 Form 1065?

No, don't attach the entire original return. However, if you're attaching supporting schedules or forms that were part of the original return to show what changed, mark them clearly "Copy Only—Do Not Process" at the top. Attach new versions of any schedules that have changed amounts.

Q6: Can I amend a 2013 partnership return in 2025?

Generally, no. The statute of limitations for filing an amended return or AAR is three years from the later of the filing date or the due date (excluding extensions) of the original return. For 2013 calendar-year partnerships, this deadline passed in 2017. Exceptions exist only in limited circumstances such as when the IRS has initiated an audit within the statute period.

Q7: What if only one line item needs correction—do I still complete the entire form?

Yes. Complete the entire Form 1065-X, but you only need to show amounts in the three-column format for line items that are changing or are related to items that are changing. For lines with no changes, you can enter the same amount in columns (a) and (c) and leave column (b) at zero, or simply skip those lines if they're not relevant to understanding your corrections. Always provide detailed explanations in Part V for every change you're making.

Sources

Sources:
All information in this guide comes from official IRS sources including About Form 1065-X, Instructions for Form 1065-X, and IRS guidance on partnership procedures. For the most current information and downloadable forms, visit IRS.gov.