The payment period for a taxable year is the period beginning with the first day of such taxable year and ending with the fifteenth day of the ninth month following the close of such year.
26 C.F.R. §1.1382-4
The payment period for a taxable year is the period beginning with the first day of such taxable year and ending with the fifteenth day of the ninth month following the close of such year.
26 C.F.R. §1.1382-4