October 16

Individuals - Filing a 2022 income tax return (Form 1040 or Form 1040-SR) and paying any tax, interest and penalties due, if an automatic six-month extension was filed (or if an automatic four-month extension was filed by a taxpayer living outside the United States).

Individuals - Making contributions for 2022 to certain existing retirement plans or establishing and contributing to a SEP for 2022, if an automatic six-month extension was filed.

Individuals - Filing a 2022 gift tax return (Form 709) and paying any tax, interest and penalties due, if an automatic six-month extension was filed.

Calendar-year C corporations - Filing a 2022 income tax return (Form 1120) and paying any tax, interest and penalties due, if an automatic six-month extension was filed.

Calendar-year C corporations - Making contributions for 2022 to certain employer-sponsored retirement plans, if an automatic six-month extension was filed.

October 31

Employers - Reporting income tax withholding and FICA taxes for third quarter 2023 (Form 941) and paying any tax due.

November 13

Individuals - Reporting October tip income of $20 or more to employers (Form 4070).

Employers - Reporting income tax withholding and FICA taxes for third quarter 2023 (Form 941), if you deposited on time and in full all of the associated taxes due.