Got an Amended or Late K-1? What Owners and Entities Need to Do Next

A late K-1 is annoying. An amended K-1 that shows up after you already filed is worse. Your first instinct may be to amend your own return immediately, or to ignore the new form and hope nobody notices. Both instincts can be wrong.

The correct response depends on three things: what kind of entity sent the K-1, whether a partnership is under the centralized audit regime, and whether you are the owner receiving the form or the entity sending it.

First, the K-1 Hasn't Arrived Yet

If you are still waiting on a K-1, the entity's extension does not help you. Treas. Reg. 1.6081-2(e) states that a partnership's automatic extension does not extend the time for filing a partner's return or paying the tax due on it. Your own filing deadline is your problem, separate from the entity's.

The entity has its own clock too. A partnership must furnish K-1s by the partnership return's due date, including extensions (Treas. Reg. 1.6031(b)-1T(b)). An S corporation must furnish them on or before the day it files its return (IRC 6037(b)). Late K-1s can cost the entity a per-statement penalty under IRC 6722, explained in our guide to failure to furnish K-1 penalties.

Why the Entity Type Matters So Much

For an S corporation, fixing a K-1 is fairly simple. For a partnership, it depends on the audit regime.

IRC 6031(b) contains a rule many people do not know exists: information a partnership furnishes to partners may not be amended after the due date of the partnership return, except in four situations. Those exceptions are (1) a partnership that elected out of the centralized audit regime under IRC 6221(b), (2) the modification procedures in IRC 6225(c), (3) push-out statements under IRC 6226, and (4) as otherwise provided by the IRS.

So the path splits.

S corporations and partnerships that elected out: amended return and amended K-1s

The 2025 Form 1120-S instructions tell an S corporation to correct a filed return by filing an amended Form 1120-S, checking box H(4), and attaching a statement identifying each amended line, the corrected amount, and the reason for the change. If any shareholder's K-1 information was wrong, the corporation files an amended K-1 for that shareholder with the amended return, gives the shareholder a copy, and checks the "Amended K-1" box.

The 2025 Form 1065 instructions describe the same mechanics for an amended partnership return: check box G(5) if filing electronically, attach the explanatory statement, file amended K-1s with the return, and give each affected partner a copy. A partnership that is not filing electronically uses Form 1065-X. This route is for partnerships that are not subject to the centralized audit regime, such as those with a valid election out under IRC 6221(b).

Partnerships under the centralized audit regime: an AAR, not amended K-1s

A partnership that did not elect out cannot simply reissue K-1s. The Form 1065 instructions say a BBA partnership must file an administrative adjustment request (AAR) and should not file an amended return or amended Schedules K-1. An electronically filed AAR uses Form 1065 with corrected amounts and box G(5) checked, plus Form 8082. A paper AAR uses Form 1065-X.

The AAR has its own rules under IRC 6227 and Treas. Reg. 301.6227-1:

• It can only be filed after the original partnership return has been filed.
• It must be filed within three years after the later of the date the return was filed or its original due date (IRC 6227(c)).
• It cannot be filed after the IRS mails a notice of administrative proceeding for that year.
• It must be signed by the partnership representative.
• The adjustments are taken into account in the year the AAR is filed, either by the partnership paying an imputed underpayment or by the partners under rules similar to the push-out rules of IRC 6226 (IRC 6227(b)).

When the partners take the adjustments into account, Treas. Reg. 301.6227-1(d) requires the partnership to furnish each affected partner a statement on the date the AAR is filed. That statement, not an "amended K-1," is what the partner works from. Our guides to the administrative adjustment request and the push-out election go deeper.

If You Are the Owner Who Received the New Form

You received an amended K-1 from an S corporation or elected-out partnership

Compare it line by line with what you reported. If the change affects your return, you will likely need to amend. Do not sit on it. The IRS matches K-1 data the entity files against individual returns, and IRM 4.19.3.8.12 generally treats the K-1 record with the latest "On File Date" as the valid one when more than one exists from the same entity. Once the amended K-1 is on file, that is the number you are measured against. See K-1 mismatch notices.

You received an AAR statement from a BBA partnership

Follow the statement and the form instructions that come with it. Treas. Reg. 301.6222-1 treats an AAR as part of the partnership return for consistency purposes. Example 4 in that regulation describes a partner who failed to take an AAR adjustment into account as required, and concludes the partner was inconsistent.

You think your K-1 is wrong and the entity will not fix it

The Schedule K-1 instructions for both partners and S corporation shareholders say the same thing: notify the entity and ask for a corrected K-1, do not change the items on your copy, and make sure the entity sends the corrected K-1 to the IRS. If you still report the item differently, file Form 8082 with your return to identify the inconsistency. IRC 6222(c) (partners) and IRC 6037(c)(2) (shareholders) protect you only for the items you identify. Our guide to consistent reporting under Section 6222 explains the stakes.

If You Are the Entity Sending the Correction

1. Identify your regime. S corporation, elected-out partnership, or BBA partnership. The answer controls everything else.
2. Check the timing. For a BBA partnership, confirm the three-year AAR window under IRC 6227(c) is still open and no notice of administrative proceeding has been mailed.
3. Fix the K-1 that goes to the IRS, not just the owner's copy. The IRS matches against what the entity files.
4. Tell the owners promptly. They may have their own returns to amend, and the sooner they know, the sooner they can act.
5. Think about state returns. Both sets of instructions note that a change to the federal return may affect the entity's state return.

Correcting a K-1 quickly can also matter for penalties. Under IRC 6722(b), a payee statement failure corrected within 30 days of the due date, or by August 1 of that year, is penalized at a reduced amount.

If an amended or late K-1 has created a problem with the IRS, call the Law Offices of Darrin T. Mish, P.A. in Tampa, Florida at 813-229-7100. A K-1 is a one-page form. The rules for fixing one are not.