Calendar of Accounting Deadlines

January 15, 2016
Due date for fourth installment of 2015 estimated tax payments.

January TBD
The IRS starts processing previously stockpiled returns. Most (but not all) are processed on a first-in, first-out basis.

January 31, 2016
All 1099 and W-2 forms must be mailed by employers.

February 15, 2016
Open enrollment for tax year 2016 ends at the Health Insurance Marketplace.

March 15, 2016
Deadline for filing a 2015 S corporation or partnership return or extension.

April 18, 2016
Deadline for filing a 2015 personal, C corporation, or estates/trusts tax returns or extension.
The return or extension must be postmarked or transmitted for e-filing by Monday, April 18, 2016.
To avoid late payment penalties and interest, any additional taxes you owe must be paid by this date even if you filed an extension.
Due date for first installment of 2016 estimated tax payments.

April 25, 2016
Deadline for resubmitting or paper-filing a rejected federal return that was originally e-filed by the April 18 deadline if you did not file an extension.
Note: Although the last day to resubmit a rejected return is October 20, the April 25 deadline applies to taxpayers who owe taxes and want to avoid the late-filing penalty.
Deadline for resubmitting or paper-filing a rejected extension that was originally e-filed by the April 18 deadline.

June 15, 2016
Deadline for filing a 2015 personal return for U.S. citizens or residents living and working abroad, including military duty.
Due date for second installment of 2016 estimated tax payments.

September 15, 2016
Final deadline to file your 2015 S corporation or partnership tax return if you filed an extension.
Due date for third installment of 2016 estimated tax payments.

September 30, 2016
Final deadline to file your 2015 estate/trust tax return if you filed an extension.

October 17, 2016
Final deadline to file your 2015 personal or C corporation tax return if you filed an extension.

October 20, 2016
Final deadline to resubmit a rejected return that was originally e-filed on or before October 17.
If you’re expecting a refund and miss the October 20 e-file cutoff date, you have until April 15, 2019 (October 15, 2019 if you filed an extension) to file a paper return and claim your 2015 refund.