Interest on deficiency.
Section 129
SEC. 129. Interest on deficiency.—Interest upon the amount determined as deficiency, shall be paid upon notice and demand from the Commissioner, and shall be collected as a part of the tax, at the rate of fourteen per centum per annum, from the due date of the tax to the date the deficiency is assessed: Provided, That the maximum amount that may be collected as interest on deficiency shall in no case exceed the amount corresponding to a period of three years, the present provisions regarding prescription to the contrary notwithstanding.