Ratable monthly portion of original issue discount
(2) Ratable monthly portion of original issue discount(i) General rule. Except when subdivision (ii) of this subparagraph applies, the term ratable monthly portion of original issue discount means an amount equal to the original issue discount divided by the sum of the number of complete months (plus any fractional part of a month) beginning on the date of original issue and ending the day before the stated maturity date of such obligation. (ii) Reduction for purchase allowance. With respect to an obligation which has been acquired by purchase (within the meaning of subparagraph (4) of this paragraph), the term ratable monthly portion of original issue discount means the lesser of the amount determined under subdivision (i) of this subparagraph or an amount equal to: