Fiduciary income tax returns for trusts and calendar year estates were due on April 15th (well, actually April 18th this year…). If you requested an extension of time to file your return, then those returns are coming due.
Federal (and most states) extensions for fiduciary income tax returns are for 5 months. (See this article regarding the final federal regulations on five month extensions.) Therefore, these extended fiduciary income tax returns are due to the IRS (and most states) by Thursday, September 15th.
Note: the extension is based on the original due date of the tax returns (that is, 5 months from April 15th) and not based on the “extra” days caused by Emancipation Day and the weekend last April. [See Reg. §1.6081-6(a)(1), which reads in part “automatic 5-month extension of time to file the return after the date prescribed for filing the return” (emphasis added).]
- Federal Fiduciary Five-Month Extension (fiduciaryincometax.wordpress.com)