Calendar-year bankruptcy estates: File a 2024 income tax return (Form 1041) if an automatic six-month extension was filed. Pay any tax, interest and penalties due.

Calendar-year C corporations: File a 2024 income tax return (Form 1120) if an automatic six-month extension was filed and pay any tax, interest and penalties due.

Calendar-year C corporations: Make contributions for 2024 to certain employer-sponsored retirement plans if an automatic six-month extension was filed.

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

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

Individuals: File a 2024 income tax return (Form 1040 or Form 1040-SR) 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 and Puerto Rico). Pay any tax, interest and penalties due.

Individuals: Make contributions for 2024 to certain existing retirement plans or establish and contribute to a SEP for 2024 if an automatic six-month extension was filed.

Individuals: File a 2024 gift tax return (Form 709), if applicable, and pay any tax, interest and penalties due if an automatic six-month extension was filed.