The provisions of this title, to the extent that they relate to the unemployment trust fund, shall be operative only so long as such unemployment trust fund continues to exist and so long as the secretary of the treasury of the United States of America continues to maintain for this state a separate book account of all funds deposited therein for this state for benefit purposes, together with this state’s proportionate share of the earnings of such unemployment trust fund, from which no other state is permitted to make withdrawals. If and when such unemployment trust fund ceases to exist, or such separate book account is no longer maintained, all moneys, properties or securities therein, belonging to the unemployment compensation fund of this state shall be transferred to the treasurer of the unemployment compensation fund, who shall hold, invest, transfer, sell, deposit, and release such moneys, properties, or securities in a manner approved by the commissioner, in accordance with the provisions of this title: PROVIDED, That such moneys shall be invested in the following readily marketable classes of securities: Bonds or other interest bearing obligations of the United States of America: AND PROVIDED FURTHER, That such investment shall at all times be made so that all the assets of the fund shall always be readily convertible into cash when needed for the payment of benefits. The treasurer shall dispose of securities or other properties belonging to the unemployment compensation fund only under the direction of the commissioner.