Treas. Reg. § 11.412(c)-11

(a) In general. Section 412(c)(2)(B) provides that, at the election of the administrator of a plan which includes a trust qualified under section 401(a) or of a plan which satisfies the requirements of section 403(a) or section 405(a), the value of a bond or other evidence of indebtedness which is held by the plan and which is not in default as to principal or interest may be determined on an amortized basis running from initial cost at purchase to the amount payable at maturity (or, in the case of a bond which is callable prior to maturity, the earliest call date). So long as this election is in effect, the value of any such evidence of indebtedness shall, for purposes of section 412, be determined on such an amortized basis rather than on a method taking into account fair market value as described in section 412(c)(2)(A).

(b) Manner of making election. The election to value evidences of indebtedness in accordance with paragraph (a) of this section shall be made by a statement to that effect attached to and filed as a part of the annual return of the plan required under section 6058 of the Code.

(c) Effect of election. The election provided by section 412(c)(2)(B), once made, will affect the valuation of all evidences of indebtedness, not in default as to principal or interest, which are held by the plan for the plan year for which the election is made and any evidences of indebtedness which are subsequently acquired by the plan. The value of any evidence of indebtedness which is in default as of the valuation date for the plan year must be determined on the basis of any reasonable actuarial method of valuation which takes into account fair market value in accordance with section 412(c)(2)(A) and must continue to be so valued until the indebtedness is no longer in default.

(d) Consent to revoke required