March 15

Calendar-year S corporations: File a 2023 income tax return (Form 1120-S) and provide each shareholder with a copy of Schedule K-1 (Form 1120S) or a substitute Schedule K-1 or file for an automatic six-month extension (Form 7004). Pay any tax due.

March 15

Calendar-year partnerships: File a 2023 income tax return (Form 1065 or Form 1065-B) and provide each partner with a copy of Schedule K1 (Form 1065) or a substitute Schedule K1 or request an automatic six-month extension (Form 7004).

March 15

Employers: Deposit Social Security, Medicare and withheld income taxes for February if the monthly deposit rule applies

March 15

Employers: Deposit nonpayroll withheld income tax for February if the monthly deposit rule applies.

April 1

Employers: Electronically file 2023 Form 1097, Form 1098, Form 1099 (other than those with an earlier deadline) and Form W-2G.

April 10

Individuals: Report March tip income of $20 or more to employers (Form 4070).