All institutions and departments which withdraw funds from the State Treasury, all agencies and departments of the state government whose funds are not deposited in the State Treasury, and all agencies and departments of the state government which maintain imprest funds are hereby authorized, empowered and directed to deposit their funds, except and less an amount approved by the auditor which shall be sufficient to cover disbursements for current operations, at interest with any qualified depository of the state at a rate of interest numerically equal to or greater than one-half of one percent (½ of 1%) below the bank discount rate on United States Treasury bills of comparable maturity as determined by the State Depository Commission. Such institutions and departments may, to the extent that they are unable to invest in certificates of deposit for periods of fourteen (14) days or longer at a rate numerically equal to or greater than one-half of one percent (½ of 1%) below the treasury bill rate, deposit funds in sums of less than One Hundred Thousand Dollars ($100,000.00) in such other type of interest-bearing account as may be now or hereafter authorized by law. Interest earned on funds withdrawn from the General Fund shall be deposited in the General Fund; interest earned on other funds shall be deposited to the fund from which the investment was made, unless otherwise required by law. Any agency not reporting through the State Treasurer’s office shall file with the Legislature an annual report showing monthly balances, monthly investments and interest earned for the preceding fiscal year or part thereof. A depository holding funds pursuant to this section shall be eligible to hold such funds to the extent that it is qualified as a depository for state funds.