Here are some of the key Q3 2019 deadlines for businesses and other employers that are tax related. Keep in mind that this list isn’t all-inclusive, so there may be additional deadlines that apply to you. July 31 Report income tax withholding and FICA taxes for the second quarter of 2019 (Form 941) and pay any tax due. (See the exception below, under “August 12.”) File a 2018 calendar-year retirement plan report (Form 5500 or Form 5500-EZ) or request an extension. August 12 Report income tax withholding and FICA taxes for the second quarter of 2019 (Form 941), if you deposited on time and in full all of the associated taxes due. September 16 If a calendar-year C corporation, pay the third installment of 2019...