Jeremy Siegel: S&P's Earnings Wrong

Author's Avatar
Feb 26, 2009
Jeremy Siegel, professor of finance at the Wharton School at the University of Pennsylvania and market guru, published an opinion piece in The Wall Street Journal on how the S&P 500 had misstated its earnings.


“A simple example can illustrate S&P’s error. Suppose on a given day the only price changes in the S&P 500 are that the largest stock, Exxon-Mobil, rose 10% in price and the smallest stock, Jones Apparel Group, fell 10%. Would S&P report that the S&P 500 was unchanged that day? Of course not. Exxon-Mobil has a market weight of over 5% in the S&P 500, while the weight of Jones Apparel is less than .04%, so that the return on Exxon-Mobil is weighted 1,381 times the return on Jones Apparel. In fact, a 10% rise in Exxon-Mobil’s price would boost the S&P 500 by 4.64 index points, while the same fall in Jones Apparel would have no impact since the change is far less than the one-hundredth of one point to which the index is routinely rounded.


Yet when S&P calculates earnings, these market weights are ignored. If, for example, Exxon-Mobil (XOM, Financial) earned $10 billion while Jones Apparel(JNY, Financial) lost $10 billion, S&P would simply add these earnings together to compute the aggregate earnings of its index, ignoring the vast discrepancy in the relative weights on these firms. Although the average investor holds 1,381 times as much stock in Exxon-Mobil as in Jones Apparel, S&P would say that that portfolio has no earnings and hence an “infinite” P/E ratio. These incorrect calculations are producing an extraordinarily low reported level of earnings, high P/E ratios, and the reported fourth-quarter “loss.”


While the current P/E ratio of the S&P 500 is listed at 12.5, it should be closer to 9.4. He gives good reasons why investors shouldn’t fool themselves into thinking the market is still overvalued. And when a guru like Siegel believes that the market is undervalued, we should all take notice.



To read his full commentary, go to the full Wall Street Journal article.