For regulations concerning interest on underpayment, nonpayment, or extensions of time for payment of tax, see § 301.6601-1 of this chapter (Regulations on Procedure and Administration).
26 C.F.R. §25.6601-1
For regulations concerning interest on underpayment, nonpayment, or extensions of time for payment of tax, see § 301.6601-1 of this chapter (Regulations on Procedure and Administration).
26 C.F.R. §25.6601-1