Certain tax return and extension due dates will change for taxable years ending on or after December 31, 2016, based on provisions included in the Surface Transportation and Veterans Health Care Choice Improvement Act of 2015 that was signed into law on July 31st, 2015. The changes represent years of lobbying by The American Institute of CPAs to have a more logical flow of tax return due dates, especially to have pass-through entity returns and the resulting Form K-1s due before individual and corporate tax returns affected by the information.
New Due Dates
The main change is that partnership tax returns are due a month earlier (two and half months after year end) on March 15th. C Corporations are now due three and half months after year end (see chart below for nuances related to ‘6/30’ C Corporation fiscal year-ends).
The table below highlights the new and existing original and extension due dates by form type.
| Return | Current Due Dates | New Due Dates | Notes |
| Individual, Form 1040 | April 15th
Extendable to October 15th |
April 15th
Extendable to October 15th |
No changes |
| Partnership, Form 1065 | April 15th
Extendable to September 15th |
March 15th
Extendable to September 15th |
Fiscal year partnerships will have a due date the 15th day of the 3rd month after year-end with a six-month extension |
| S Corporation, Form 1120S | March 15th
Extendable to September 15th |
March 15th
Extendable to September 15th |
No changes for S Corporation entities |
| C Corporation with a 12/31 Year-End, Form 1120 | March 15th
Extendable to September 15th |
April 15th through 2025
Extendable to September 15th 2026 and thereafter: extendable to October 15th |
The extension due date for calendar year-end C Corporations will remain the same through 2025 and then change by a month in 2026 |
| C Corporation with a 6/30 Year-End, Form 1120 | September 15th
Extendable to March 15th |
Pre-2026: September 15th
Post-2026: October 15th |
C Corporations with 6/30 year-ends will not have their original due date change until 2026 |
| C Corporation with all other Year-Ends, Form 1120 | 15th day of 3rd month after year-end
Extendable to the 15th day of 9th month after year-end |
15th day of 4th month after year-end
Extendable to the 15th day of 10th month after year-end |
For C Corporations with year-ends other than 12/31 or 6/30 |
| Trusts & Estates, Form 1041 | April 15th | April 15th | Trust and estate returns will have a 5 1/2 month extension |
| Exempt Organizations, Form 990 | May 15th
Extendable to August 15th Second extension to November 15th |
May 15th
Extendable to November 15th |
Instead of two three-month extensions, Exempt Organizations will have one six-month extension |