The amount of money belonging to the several funds in the county treasury of each county in the state which is required to meet the current needs and demands of no more than seven (7) business days shall be kept on deposit in or through qualified financial institutions whose accounts are insured by the Federal Deposit Insurance Corporation or the Federal Savings and Loan Insurance Corporation, or in or through some of them doing business in the several counties, provided that where there is no such financial institution in a county qualifying as a depository, some such financial institution in an adjoining county may qualify as a depository. All such deposits shall be subject to payment when demanded on warrant issued by the clerk of the board of supervisors on the order of the said board or on the allowance of a court authorized to allow the same. Each financial institution qualifying as such county depository shall not be required to pay interest to the county for the privilege of holding the deposits unless federal law permits the payment of interest on such deposits, in which case the maximum permitted interest rate shall be paid on such deposits. Where more than one (1) financial institution in a county offers to qualify as a depository, the board of supervisors may allocate such money to each qualified financial institution as nearly as practicable in proportion to their respective net worth, and may adopt the rules for receiving such deposits.