(a) Special Funds. Each pension and retirement board shall have a special trust fund or funds on deposit with the Treasurer for the purpose of segregating its revenues from the other money of the City.
(b) Control of Special Funds. The board of each pension and retirement system shall have control over their respective funds. Transfers or expenditures shall be drawn upon funds only upon demands signed by the chief accounting employee of the board. All payments from the funds shall be made upon demands prepared and approved in accordance with the provisions of the Charter.
(c) Master Trustee or Custodian. Each pension and retirement board, in its sole discretion, may designate one or more master trustees or custodians to hold securities and funds of the system for the purpose of carrying out the investment policies and decisions of the board.
(d) Fund Earnings. The money in any pension or retirement system fund shall be invested at the sole and exclusive direction of the respective board and all earnings shall be credited to the respective funds by the Treasurer or the Master Trustee or Custodian designated by the respective board.