Final answer:
Without specific financial data, an accurate estimate for the Weighted Average Cost of Capital cannot be provided, but a tentative suggestion based on available information would be an effective rate of return of 4%, which may be close to the company's WACC.
Step-by-step explanation:
Estimating the Weighted Average Cost of Capital (WACC) for a company involves considering the cost of various sources of capital, which can include equity, debt, and any other funding sources. The WACC is the average rate of return a company is expected to pay its security holders to finance its assets. Without more specific data about the company's structure of finances, such as the proportion of debt to equity, the cost of equity, and the after-tax cost of debt, it is not possible to provide a precise estimate of the WACC.
However, based on the information provided, it appears that the firm has an effective rate of return of 4%. This figure suggests that the firm might be factoring in the ability to capture a 5% return to society against a cost of financial capital of 9%. If this rate is reflective of the company's overall cost of capital after adjusting for societal benefits, then a good estimate for the company's WACC used to discount project cash flows may be closer to the provided effective rate of return, which is the 4% figure.
Nevertheless, this estimate does not consider all the specific factors that need to be taken into account when calculating WACC. It should be used cautiously and ideally, more comprehensive financial information should be gathered to calculate a more accurate WACC.