; or (II) any other portfolio prescribed by the Secretary of the Treasury in regulations which has a similar risk profile to the portfolios described in subclause (I) and is equally protective of the interests of participants and beneficiaries. Once implemented, such a portfolio shall be maintained until all liabilities to participants and beneficiaries in pay status at the time of the loan are satisfied. (ii) Fiduciary duty Any investment manager of a portfolio under this subparagraph shall acknowledge in writing that such person is a fiduciary under the Employee Retirement Income Security Act of 1974 with respect to the plan. (iii) Treatment of participants and beneficiaries Participants and beneficiaries covered by a portfolio under this subparagraph shall continue to be treated as participants and beneficiaries of the plan. (D) Accounting (i) In general Annuity contracts purchased and portfolios implemented under this paragraph shall be accounted for separately from the other assets of the plan, and the proceeds thereof shall be used solely to provide the benefits described in paragraph (1) until all such benefits have been paid. (ii) Oversight of non-annuity investments (I) In general Any portfolio implemented under this paragraph shall be subject to oversight by the Pension Rehabilitation Administration, including a mandatory triennial review of the adequacy of the portfolio to provide the benefits described in paragraph (1) and approval (to be provided within a reasonable period of time) of any decision by the plan sponsor to change the investment manager of the portfolio. (II) Remedial action If the triennial review under subclause (I) determines an inadequacy, the plan sponsor shall take remedial action to ensure that the inadequacy will be cured within 5 years of the review. (E) Ombudsperson The Participant and Plan Sponsor Advocate established under section 4004 of the Employee Retirement Income Security Act of 1974 shall act as ombudsperson for participants and beneficiaries on behalf of whom annuity