(28) Additional requirements relating to employee stock ownership plans.— (A) In general .— In the case of a trust which is part of an employee stock ownership plan (within the meaning of section 4975(e)(7) ) or a plan which meets the requirements of section 409(a), such trust shall not constitute a qualified trust under this section unless such plan meets the requirements of subparagraphs (B) and (C). (B) Diversification of investments.— (i) In general .— A plan meets the requirements of this subparagraph if each qualified participant in the plan may elect within 90 days after the close of each plan year in the qualified election period to direct the plan as to the investment of at least 25 percent of the participant’s account in the plan (to the extent such portion exceeds the amount to which a prior election under this subparagraph applies). In the case of the election year in which the participant can make his last election, the preceding sentence shall be applied by substituting “50 percent” for “25 percent”. (ii) Method of meeting requirements .— A plan shall be treated as meeting the requirements of clause (i) if— (I) the portion of the participant’s account covered by the election under clause (i) is distributed within 90 days after the period during which the election may be made, or (II) the plan offers at least 3 investment options (not inconsistent with regulations prescribed by the Secretary) to each participant making an election under clause (i) and within 90 days after the period during which the election may be made, the plan invests the portion of the participant’s account covered by the election in accordance with such election. (iii) Qualified participant .— For purposes of this subparagraph, the term “qualified participant” means any employee who has completed at least 10 years of participation under the plan and has attained age 55. (iv) Qualified election period .— For purposes of this subparagraph, the term “qualified election period” means the 6-plan-year period beginning with the later of— (I) the 1st plan year in which the individual first became a qualified participant, or (II) the 1st plan year beginning after December 31, 1986 . For purposes of the preceding sentence, an employer may elect to treat an individual first becoming a qualified participant in the 1st plan year beginning in 1987 as having become a participant in the 1st plan year beginning in 1988. (v) Exception .— This subparagraph shall not apply to an applicable defined contribution plan (as defined in paragraph (35)(E)). (C) Use of independent appraiser .— A plan meets the requirements of this subparagraph if all valuations of employer securities which are not readily tradable on an established securities market with respect to activities carried on by the plan are by an independent appraiser. For purposes of the preceding sentence, the term “independent appraiser” means any appraiser meeting requirements similar to the requirements of the regulations prescribed under section 170(a)(1).