CME Group (CME) has lost more than half of its market value over the past three months and the stock price has cratered by nearly three-quarters in the past year. As illustrated in the accompanying three-month chart and table of valuation parameters [click to enlarge] for the major U.S.-listed exchanges, CME is extremely oversold and trades at less than two-thirds of book value (0.66) despite its position as the world's largest futures exchange with a major new source of revenue in the form o