Many owners wind up a US company and assume the final return covers everything. It doesn't. The two filings have different deadlines, and missing Form 966 is an easy mistake for Australian owners closing a US subsidiary. This article covers who files, when, what to attach, and how Form 966 fits with the final return and wider closure.
Key Takeaways
- Form 966 and the final Form 1120 serve different purposes and are filed separately.
- Deadline for Form 966 runs from the date the plan is adopted.
- Attach the certified plan or resolution to Form 966.
- Liquidation still requires the final return, payroll filings and state dissolution.
What Form 966 Reports and When It Applies
Who must file
A corporation files Form 966 when it adopts a resolution or plan to dissolve or liquidate any of its stock. The form covers complete and partial liquidations.
It includes a return-type box for Form 1120-S, so S corporations can be within scope. LLCs that elected corporate tax treatment through Form 8832 are generally treated as corporations for this purpose.
Several situations are carved out in the IRS Form 966 instructions:
- Tax-exempt organisations should not file.
- Deemed liquidations, such as those from a section 338 election, are not filed.
- Qualified subchapter S subsidiaries (QSubs) are excluded (not all S corporations).
- Foreign corporations with no US return filing requirement are generally not required to file.
Mergers and reorganisations need care. The instructions' exceptions concern recognition of gain or loss, and Regulation 1.6043-1 contains no blanket merger exemption. Get advice before assuming you are exempt.
What the form contains
Form 966 is a notice. It gives the IRS the following details:
- Legal name, address and EIN
- Incorporation date and place
- Complete or partial liquidation
- Plan adoption date
- Prior and final tax-year ends
- Shares outstanding at adoption
- Amendment dates
- The Code section that applies, such as section 331 or 332
It is not a tax return, and it does not complete the state-law dissolution.
What triggers the deadline
The form is due within 30 days after the plan or resolution is adopted. The clock does not start when operations stop, when state paperwork is filed, or when the last asset is distributed.
If the plan is later amended or supplemented, another Form 966 is due within 30 days of that adoption. It must show the earlier filing date on line 11 and attach the certified amendment.
Does Form 966 Need to Be Attached to Form 1120?
The direct answer
The Form 966 instructions say to file it with the IRS service centre where the corporation files its income tax return. They do not direct you to attach it to Form 1120 or 1120-S. Treat it as a standalone submission.
The purposes differ:
- Form 966: reports the adopted dissolution or liquidation plan.
- Form 1120: reports taxable income, gains, losses, deductions and the final tax position.
What attaches to Form 966
Attach a certified copy of the adopted resolution or plan. Add certified copies of any amendments or supplements not previously filed.
The attachment should match your corporate records. The adoption date, transaction description and authorisation should line up with the board or shareholder minutes.
Coordinating the two filings
A workable sequence looks like this:
- Confirm the formal adoption date of the plan.
- File Form 966 with the certified plan within 30 days.
- Prepare the final Form 1120 (or 1120-S) under its own instructions.
- Mark the return as final and reconcile dates and transaction details against Form 966.
The final return may need further forms. Asset sales can bring in Form 4797, Schedule D or Form 8594, and liquidating distributions of US$600 or more are generally reported on Form 1099-DIV (boxes 9 and 10).
What if Form 966 went in with the Form 1120 package?
Bundling it with the return does not safely satisfy the separate filing requirement. File it correctly as soon as you notice, because the 30-day window may already have passed.
Speak to a tax professional if the filing is late, the resolution date is unclear, the plan was amended, or the return and state dissolution records conflict. The Form 966 instructions confirm the obligation but do not set out a standalone late-filing penalty, so do not rely on figures quoted elsewhere.
How to File Form 966 Correctly
Use the current form and gather records
Download the form and instructions from the IRS. The current version is the October 2016 revision, which remains current. Avoid saved copies, third-party samples and unofficial mailing addresses.
Before you start, collect:
- Legal entity name and EIN
- Incorporation details
- The approved plan or resolution
- Prior return information
- Share counts at adoption
- Any amendment history
Complete it consistently
Work from the corporate records, not memory. Common slips to avoid:
- Using a trade name instead of the legal name
- Entering dates that differ from the minutes
- Guessing the Code section
- Reporting share numbers from the wrong date (the form asks for shares outstanding at adoption)
Certify the plan
Confirm the plan was formally adopted and certified under the corporation's own procedures. Resolve drafts, unsigned documents and versions that show a different adoption date before you file.
Sign and submit
The president, vice president, treasurer, assistant treasurer, chief accounting officer or another authorised officer signs and dates the form. A receiver, trustee or assignee signs if acting for the corporation.
The IRS does not confirm electronic signing or standalone e-filing of Form 966. The "e-file" entries on lines 5 and 7e relate to the referenced income tax return, not to Form 966 itself. Assume a signed paper filing unless the IRS says otherwise.
The instructions give no single universal address. Send the form to the service centre where the corporation files its income tax return.
Keep proof
Keep the signed form, certified attachment, approvals, mailing records, delivery confirmation and any IRS letters. If the IRS cannot find the filing, or later queries your dissolution date, this file protects you.
How Form 966 Fits With the Final Form 1120 and Business Closure
The final return
A corporation files a final income tax return for its last tax period. On Form 1120, tick item E ("Final return") if the corporation will no longer exist. On Form 1120-S, tick item H(1) and mark Final K-1 on every Schedule K-1.
Under the 2025 Form 1120 instructions, a dissolved corporation's return is generally due on the 15th day of the 4th month after dissolution. For Form 1120-S, the deadline is the 15th day of the 3rd month after dissolution. Form 7004 generally gives six months to file but does not extend the time to pay tax.
Other federal filings
Depending on activity, these may apply:
- Forms 941 or 944, with the final-return box ticked and the date of final wages entered
- Form 940 for the year of final wages
- Forms W-2 and W-3
- Form 1099-NEC for contractors, generally due 31 January
- Form 1099-DIV for liquidating distributions
Not every company needs all of them. The package depends on employees, contractors, assets, liabilities and shareholders.
State dissolution and IRS account closure
Form 966 does not replace state dissolution filings. Check state requirements separately.
For the IRS account, the IRS closing guidance says to send a letter with the legal name, EIN, business address and reason for closing. All required returns must be filed and all taxes paid first. The IRS pages list different mailing addresses, so confirm the current one before posting.
An EIN cannot be cancelled. It can be deactivated, and it stays the entity's permanent federal taxpayer ID.
Common Mistakes and a Practical Filing Checklist
Errors to avoid
- Counting the 30 days from the wrong date
- Attaching Form 966 only to Form 1120
- Leaving out the certified plan
- Using entity details that differ across documents
- Failing to file an amendment when details change
- Relying on outdated instructions
State dissolution, ceasing operations, Form 966, the final return and account closure can all fall on different timelines. Track each one.
Pre-submission checklist
- Confirm the federal tax classification.
- Identify the formal plan adoption date.
- Obtain the certified plan or resolution.
- Prepare Form 966 and confirm the signer.
- File it separately from the final Form 1120.
- Complete payroll, information returns and other filings.
- Keep proof of submission.
Then reconcile Form 966 against:
- Minutes and shareholder approvals
- State filings and prior returns
- Stock records and asset-sale documents
- The final return
Getting help
VJM Global supports Australian businesses with US entities on tax compliance, including coordinating final corporate returns, dissolution documents and federal compliance review. If your entity classification, liquidation structure, deadline, signature method or attachments are unclear, talk to VJM Global or another qualified tax professional before filing.
Frequently Asked Questions
When should Form 966 be filed?
Within 30 days after the corporation adopts its dissolution or liquidation resolution or plan. An amendment or supplement starts a new 30-day period. Check the current instructions for exceptions.
Where should I file IRS Form 966?
File it with the IRS service center where the corporation files its income tax return, as the instructions direct. Do not rely on an old address.
Can Form 966 be signed electronically?
Electronic signing or standalone e-filing for Form 966 is not confirmed by the IRS. A signed paper form is the safe route. Verify the latest IRS position before relying on anything else.
Does Form 966 need to be attached to Form 1120?
No. It is generally filed separately. The certified dissolution or liquidation plan is what attaches to Form 966.
What documents must be attached to Form 966?
A certified copy of the resolution or plan, plus certified copies of any amendments or supplements not previously filed. Confirm against the current instructions.
