Tax Deadlines for September 15
Individuals.
Make a payment of your 2023 estimated tax if you're not paying your income tax for the year through withholding (or won't pay in enough tax that way). Use Form 1040-ES. This is the third installment date for estimated tax in 2023. For more in-formation, see Pub. 505.
Partnerships.
File a 2022 calendar year return (Form 1065). This due date applies only if you timely requested an automatic 6-month extension. Otherwise, see Partnerships under March 15, earlier. Provide each partner with a copy of their final or amended Schedule K-1 (Form 1065) or substitute Schedule K-1 (Form 1065) and, if applicable, Schedule K-3 (Form 1065) or substitute Schedule K-3 (Form 1065).
S corporations.
File a 2022 calendar year income tax return (Form 1120-S) and pay any tax, interest, and penalties due. This due date applies only if you timely requested an automatic 6-month extension of time to file the return. Otherwise, see S corporations under March 15, earlier. Provide each shareholder with a copy of their final or amended Schedule K-1 (Form 1120-S) or substitute Schedule K-1 (Form 1120-S) and, if applica-ble, Schedule K-3 (Form 1120-S) or substitute Schedule K-3 (Form 1120-S).
Corporations.
Deposit the third installment of estimated income tax for 2023.