CT-5.1: Request for Additional Extension of Time to File (for franchise/business taxes, MTA surcharge, or both) (2025)

Who files this form

Form CT-5.1 is used to request additional time to file the franchise/business tax returns, MTA surcharge returns, or both listed on the form under Tax Law Articles 9, 9-A, 13, and 33.

• If you file more than one type of tax return, file a separate extension form for each type.
• Combined-return filers typically file one Form CT-5.1 for the group. However, a corporation becoming a member of a new combined group or being added to an existing group must also file Form CT-5.1 separately for that first tax year.

What you'll need

Have the information requested on the form ready:

• The corporation’s legal name, trade name or DBA, EIN, file number, mailing address, and business telephone number.
• State or country of incorporation and date of incorporation. Foreign corporations are also asked for the date they began business in New York State.
• The beginning and ending dates of the tax period.
• The return or returns for which you are requesting more time, and a detailed explanation of why you need it.
• The authorized person’s name, title, signature, contact information, and date.
• Paid preparer information, if applicable.

For a separate request by a corporation joining a combined group, have the EIN of the group’s designated agent for CT-3-A filers or parent for CT-33-A filers.

How to file

1. Complete the business information and enter both the beginning and ending dates of the tax period.
2. Mark the box for the return you want to extend. Mark both boxes if requesting additional time for a state tax return and its associated MTA surcharge return of the same type.
3. Explain in detail why you need additional time to file.
4. If filing separately because you are joining a combined group, complete the business information and line A, then mark line B for a new group or line C for an existing group.
5. Have the authorized person complete and sign the certification that the document and any attachments are true, correct, and complete to the best of their knowledge and belief.

The form says to see the instructions for where to file. No instructions were supplied, so the provided text does not give a mailing address or e-file directions.

Common mistakes

• Leaving out the tax period. All filers must enter the beginning and ending dates.
• Marking only one box when requesting both extensions. Mark both boxes for a state return and its associated MTA surcharge return of the same type.
• Using one extension form for different return types. A separate extension form is required for each type of tax return.
• Overlooking the combined-group exception. A corporation joining a new or existing combined group must also file separately for its first year in that group.
• Omitting the designated agent’s or parent’s EIN on line A. The form warns that this may delay processing and may result in penalties and interest.

Questions people ask

Can I request more time for both a state tax return and its MTA surcharge return?

Yes. Mark both boxes when the returns are of the same type, such as CT-183 and CT-183-M.

Can one CT-5.1 cover different types of tax returns?

No. If you file more than one type, such as CT-183 and CT-184, you must file a separate extension form for each type.

Do I need to explain why I need more time?

Yes. The form asks for a detailed explanation of why you need additional time to file.

What if my corporation is joining a combined group?

You must also file CT-5.1 separately for the first tax year you are included in a new group or added to an existing group. Complete the business information and line A, then mark line B or C as appropriate.

How can I update the corporation’s address or phone information?

The form says you can update this information online. It directs you to the Business information section in Form CT-1.

Official sources

• https://www.tax.ny.gov/pdf/current_forms/ct/ct5_1.pdf