Section 23 — Computation of pro rata amount of discount on a zero coupon bond for purpose of section 32(d)

(1) For the purposes of section 32(d), the pro rata amount of discount on a zero coupon bond shall be computed in the following manner:—
(a) the period of life of the bond shall be converted into number of calendar months and, for this purpose, where the calendar month in which the bond isissued or the bond matures or is redeemed, contains a part of a calendar month then,—(i) if such part is fifteen days or more than fifteen days, it shall be increased to one calendar month; and(ii) if such part is less than fifteen days, it shall be ignored;(b) the amount of discount shall be divided by the number of calendar months determined in accordance with clause (a); and
(c) where one or more than one calendar month out of calendar months determined in accordance with clause (a) is or are included in a tax year, theamount determined in accordance with clause (b) shall be multiplied by the number of calendar months so included and the amount so arrived at shallbe taken to be the pro rata amount of discount for that tax year.