Effective for tax years beginning after December 31, 2015, the due date for filing federal tax returns for C corporations and partnerships were revised.  See Public Law 114-41, the “Surface Transportation and Veterans Healthcare Choice Improvement Act of 2015”.  As shown in the table below, C Corporations now have an additional month—until April 15—to file their federal returns, whereas partnerships now have one month less to file their federal returns, which are now due March 15.

Tax Return Filing Deadlines

Prior Law New Law Effective Date
Corporation 15th day of 3rd month* March 15** 15th day of 4th month April 15 Federal: tax years beginning after 12/31/15

Massachusetts: tax returns due on/after 1/1/18***

Partnership 15th day of 4th month April 15 15th day of 3rd month March 15

*Following the close of the taxpayer’s tax year
**Calendar-year taxpayers.
*** Relief granted by TIR 17-3 and TIR 17-5.

Subsequently, the Massachusetts Legislature enacted conforming legislation to change the due dates of Massachusetts returns to match the new federal due dates.  St. 2017, c. 5, §§ 11-14.  However, the Massachusetts conformity legislation is only effective for tax returns due on or after January 1, 2018 (determined without regard to extensions), which creates a gap from the time the federal changes first take effect.  Taxpayers with Massachusetts corporate excise tax returns due during this gap period will be required to file their Massachusetts returns before their corresponding federal income tax returns are due.

To help taxpayers with Massachusetts corporate excise tax returns due during this gap period, the Department has issued guidance agreeing to waive late-filing penalties assessed against any taxpayer with a corporate excise tax return during the gap period (i.e., a return for a tax year beginning after December 31, 2015 that is due on or before December 31, 2017), so long as the taxpayer files its corporate excise tax return within one month of the statutory due date or the statutory due date on extension. See Technical Information Release (“TIR”) 17-3 (March 2, 2017) and TIR 17-5 (May 31, 2017).