July 15 Employers should deposit Social Security, Medicare and withheld income taxes for June if the monthly deposit rule applies. They should also deposit non-payroll withheld income tax for June if the monthly deposit rule applies. July 31 Report income tax withholding and FICA taxes for second quarter 2024 (Form 941) and pay any tax due. (See the exception below, under “August 12.”) File a 2023 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 second quarter 2024 (Form 941), if you deposited on time and in full all the associated taxes due. September 16 If a calendar-year C corporation, pay the third installment of 2024 estimated income taxes. If a calendar-year S corporation or partnership that...