7.Assume the following information for a company:

• There are 9 million ordinary shares.The beta of the shares is -0.4, the risk-free rate is 3% pa and the return on the market is 12% pa. The shares last traded at $10.00 per share.
• An overdraft of $15 million attracts an interest rate of 6% pa compounded monthly.
• 90-day bank bills have just been issued with a Face Value of $10m and yield of 4% pa.
• The company accounts show $8m in retained earnings and $6m in trade credit (accounts payable).
• Perpetual Preference shares exist which pay an annual a dividend of $0.30 and are currently trading at $3.60. There are 4m of these preference shares on issue.
• The corporate tax rate is 30%.

Calculate the Weighted Average Cost of Capital on an after-tax basis. What limitations apply to the use of this WACC?