(a) With the board's concurrence, the comptroller shall invest the unexpended revenue bond proceeds and the investment income of those unexpended proceeds in investments approved by law for the investment of state funds.
(b) The investment income required for project costs, and not required to be rebated to the federal government or used for debt service, as determined by the board, shall be credited to the appropriate agency. The investment income not required for project costs, not required to be rebated to the federal government, and not required for debt service shall be allocated as provided by Section 404.071.