The fair rate of return for a public utility may be arrived at by considering a number of factors, and it cannot be determined by any specific formula, except as provided for in Miss. Code Ann. § 77-3-2. However, the basic factors to be considered in arriving at the overall required rate of return are (1) the cost of debt capital, (2) the cost of preferred stock capital and (3) the cost of equity capital. The capital costs of a public utility shall be determined based on evidence of the appropriate costs for the utility's debt capital, preferred stock capital and equity capital. The overall cost of capital may be determined as weighted average of the appropriate costs of these various types of capital.
39 Miss. Code. R. 1-21-104