Additions to the tax in case of nonpayment.
Section 101
SEC. 101. Additions to the tax in case of nonpayment. — (a) Tax shown on the return. — (1) Payment not extended. — Where the amount of the tax imposed by this Chapter, or any part of such amount is not paid on the due date of the tax, there shall be collected as a part of the tax, interest upon such unpaid amount at the rate of fourteen per centum per annum, from the due date until it is paid: Provided, That the maximum amount that may be collected as interest on delinquency shall in no case exceed the amount corresponding to a period of three years, the present provisions regarding prescription to the contrary notwithstanding. (2) Payment extended. — Where an extension of time for payment of the amount of the tax has been granted, and the amount the time for the payment of which has been extended, and the interest thereon determined under subsection (2) of Section 99, is not paid in full prior to the expiration of the period of the extension, interest at the rate of fourteen per centum per annum, shall be collected on such unpaid amount from the date the same was originally due until it is paid.