in the American Savings Account Fund shall not be appropriated for any purpose other than the purposes specified in this section and may not be used for any other purpose. (f) Amounts held in trust All sums contributed to the American Savings Account Fund by a participant or by an employer for the benefit of such participant and all net earnings in such Fund attributable to investment of such sums are held in such Fund in trust for such participant. 5012. Tax treatment of the American Savings Account Fund (a) In general For purposes of the Internal Revenue Code of 1986— (1) the American Savings Account Fund shall be treated as a trust described in section 401(a) of such Code which is exempt from taxation under section 501(a) of such Code