(i) In general.
The yield on a fixed yield issue that includes a bond subject to mandatory early redemption or expected contingent redemption is computed by treating that bond as redeemed on its reasonably expected early redemption date for an amount equal to its value on that date. Reasonable expectations are determined on the issue date. A bond is subject to mandatory early redemption if it is unconditionally payable in full before its final maturity date. A bond is subject to a contingent redemption if it must be, or is reasonably expected to be, redeemed prior to final maturity upon the occurrence of a contingency. A contingent redemption is taken into account only if the contingency is reasonably expected to occur, in which case the date of occurrence of the contingency must be reasonably estimated. For example, if bonds are reasonably expected to be redeemed early using excess revenues from general or special property taxes or benefit assessments or similar amounts, the reasonably expected redemption schedule is used to determine yield. For purposes of this paragraph (b)(2)(i), excess proceeds calls for issues for which the requirements of section 1.148-2(e)(2) or (3) are satisfied, calamity calls, and refundings do not cause a bond to be subject to early redemption. The value of a bond is determined under paragraph (e) of this section.
(ii) Substantially identical bonds subject to mandatory early redemption.
If substantially identical bonds of an issue are subject to specified mandatory redemptions prior to final maturity (e.g., a mandatory sinking fund redemption requirement), yield on that issue is computed by treating those bonds as redeemed in accordance with the redemption schedule for an amount equal to their value. Generally, bonds are substantially identical if the stated interest rate, maturity, and payment dates are the same. In computing the yield on an issue containing bonds described in this paragraph (b)(2)(ii), each of those bonds must be treated as redeemed at its present value, unless the stated redemption price at maturity of the bond does not exceed the issue price of the bond by more than one- fourth of one percent multiplied by the product of the stated redemption price at maturity and the number of years to the weighted average maturity date of the substantially identical bonds, in which case each of those bonds must be treated as redeemed at its outstanding stated principal amount, plus accrued, unpaid interest. Weighted average maturity is determined by taking into account the mandatory redemption schedule.