Section 9A. There shall be an unpaid investment committee which shall have general supervision of the investment of funds retained in the group insurance commission trust fund to be used on behalf of the insured employees. Such committee shall consist of the state treasurer, who shall be a member ex officio, the members of the group insurance commission who shall be members ex officio, and one other person who shall be chosen by the aforementioned members, for a term of three years and who shall be qualified by training and experience in the investment of funds as a result of having been principally employed in such occupation for a period of at least ten years. The chairman of the investment committee shall be chosen from among its members. Each member of such committee shall continue to hold office until the expiration of his term and until the qualification of his successor. The executive director of the commission shall perform the duties of secretary of the investment committee. The commission shall furnish such clerical assistants as may be required to carry on the work of the investment committee. Subject in each instance to the approval of the investment committee established under the provisions of this section, the state treasurer shall invest and reinvest such funds to the extent not required for current disbursements as authorized by section nine in bonds, notes or other securities which are legal for the investment of funds of savings banks under the laws of the commonwealth. Not more than twenty-five per cent of the total funds of the trust fund shall be invested in bank stocks or bank holding company stocks nor shall more than one-half of said twenty-five per cent be invested in the stock of any one bank or bank holding company. The treasurer may deposit any portion of the monies to be invested, in savings banks, co-operative banks or in savings deposits in trust companies, lawfully doing business in the commonwealth for one year or more, subject, however, to the limitations set forth in section three of chapter one hundred and sixty-seven D, and may invest such funds in shares of federal savings and loan associations lawfully doing business in the commonwealth for one year or more, but the amount so invested in any one federal savings and loan association shall not at any time exceed the sum of ten thousand dollars. The commission shall have power to expend such funds which in its discretion is in the best interests of the insured employees and retired employees. The state treasurer shall make payment of such funds as authorized by the commission. A statement of all funds received, invested and expended on behalf of the insured employees shall be included in the annual report of the commission as required by section three.