Commonwealth Edison Co. (Edison), through its underwriters, sold one million shares of preferred stock at an offering price of $100 per share. Edison wanted to issue the stock with a dividend rate of 9.26 percent, but its major underwriter, First Boston Corporation (First Boston), advised that a rate of 9.44 percent should be paid. According to First Boston, a shortage of investment funds existed, and a higher dividend was necessary for a successful stock issue. Edison's management was never happy with the high dividend rate being paid on the preferred stock. Nine months later, Edison's vice chairman was quoted in the report of the annual meeting of the corporation as saying, "we were disappointed at the 9.44 percent dividend rate on the preferred stock we sold last August, but we expect to refinance it when market conditions make it feasible." Edison, pursuant to the terms under which the stock was sold, bought back the one million shares of preferred stock at a price of $110 per share. What type of stock is this