§ 1106-e. Reserve fund. There shall be a reserve fund for each project which in no event shall initially be less than five percent of the turnkey/enhanced rental project costs, exclusive of any reserve fund. Such reserve fund may be provided by the corporation or any other source and, if provided by another source, shall be provided in cash or the payment of such cash shall be assured by deposit of adequate marketable collateral prior to the payment by the corporation of any project costs, excluding advances for planning costs.