IRS Form 966 in 2026: Who Files It, the 30-Day Deadline, and What It Does Not Do

IRS Form 966, Corporate Dissolution or Liquidation, is a one-page notice that tells the IRS a corporation has decided to dissolve or liquidate. It is due within 30 days after the board or stockholders adopt the resolution, and you attach a certified copy of that resolution. It is not a tax return and it does not close your EIN.

If you are dissolving a C-corp, an S-corp, or an LLC that elected corporate tax status, Form 966 is one of three federal filings you cannot skip. The other two are the final income tax return and the EIN closure letter.

Who must file Form 966

• C corporations dissolving or liquidating, including dormant startups with no income
• S corporations
• LLCs taxed as corporations, because they made a C-corp or S-corp election on Form 8832 or Form 2553
• Corporations adopting a plan of partial liquidation

Who does not file:

• LLCs taxed as partnerships (they file a final Form 1065)
• Single-member LLCs that are disregarded entities (final Schedule C, or final Form 5472 with pro forma 1120 for foreign owners)
• Sole proprietors
• Tax-exempt organizations (they report dissolution on their final Form 990 series return)

The legal requirement is Internal Revenue Code section 6043(a). The question is not whether your corporation had activity; it is whether a corporation exists and has decided to end.

The 30-day deadline

Form 966 is due within 30 days after the date the resolution or plan is adopted. Three things trip people up:

1. The trigger is the resolution, not the state filing. If your stockholders signed a consent to dissolve on March 1 and Delaware filed your certificate on March 20, the deadline was March 31, not April 19.
2. Amendments restart the obligation. If you later amend the plan (for example, to change the liquidation terms), file another Form 966 within 30 days of the amendment, attaching the amendment.
3. Late is better than never. If you missed the window, file it now with the resolution attached. The IRS has no mechanism for refusing a late Form 966.

What the form asks for

Form 966 is short. You will need:

• Corporation name, EIN and address
• Type of return filed (1120, 1120-S, etc.) and the last tax year filed
• Date and place of incorporation
• Date the resolution or plan was adopted
• Whether it is a complete or partial liquidation
• Total number of shares outstanding at the time of adoption, by class
• Dates of any amendments
• The Internal Revenue Code section under which the corporation is liquidating, if applicable (for a routine liquidation of a founder-owned company, this is usually section 331)
• Signature of an officer

Attach a certified copy of the resolution or plan. "Certified" means an officer signs a statement that the copy is true and complete; it does not require a notary.

Where to file

Mail Form 966 to the IRS service center where the corporation files its income tax return. The address is in the form's instructions and depends on the corporation's state and whether it is enclosing a payment (it will not be). There is no e-filing option for Form 966 on its own; some tax software can include it with the final return, but the 30-day deadline usually falls before the return is prepared, so mail it separately.

Keep a copy and proof of mailing. The IRS does not send an acknowledgment.

What Form 966 does not do

It is not the final tax return. A dissolving C-corp still files a final Form 1120 for the short tax year ending on the dissolution date, with the "final return" box checked. An S-corp files a final 1120-S with final Schedule K-1s. If the corporation is 25% or more foreign-owned, a final Form 5472 attaches to the 1120.

It does not close the EIN. That takes a separate letter to the IRS after the final return is filed. See how to cancel an EIN.

It does not dissolve the corporation. The state filing (in Delaware, the Certificate of Dissolution) does that. See how to dissolve a Delaware corporation.

It does not settle shareholder tax. Shareholders who receive liquidating distributions report gain or loss under section 331 on their own returns. The corporation reports the distributions on Form 1099-DIV, boxes 9 and 10, for any shareholder who receives $600 or more.

Form 966 for a dormant corporation with nothing in it

The most common case we see: a founder incorporated a Delaware C-corp, opened a bank account, never launched, and now wants it gone. The sequence is:

1. Sign a stockholder consent to dissolve (date it)
2. Mail Form 966 with the consent attached within 30 days
3. File the Delaware Certificate of Dissolution (short form, $50, if the corporation meets the short-form conditions, starting with having no assets)
4. File the final Form 1120 showing zero income, plus Form 5472 if the founder is not a US person
5. Mail the EIN closure letter

Total federal cost: postage. Total state cost: $50 plus any franchise tax owed.

Frequently asked questions

When is Form 966 due?

Within 30 days after the resolution or plan to dissolve is adopted.

Does an LLC need to file Form 966?

Only if it is taxed as a corporation. Partnership-taxed and disregarded LLCs do not file it.

What is the penalty for not filing?

The instructions list no specific dollar penalty, but the filing is required by IRC 6043(a). File it; it costs nothing.

Does Form 966 close my EIN or replace the final return?

No. The final Form 1120 or 1120-S and the EIN closure letter are separate.

Where do I send it?

To the service center where the corporation files its income tax return, per the current instructions.

Get the federal side right

CloseWise prepares Form 966 with the resolution attached, tracks the 30-day deadline from your consent date, has the final Form 1120 (with Form 5472 for non-US owners) prepared by a licensed preparer, and prepares the EIN closure letter as part of the same closure. Start your closure.