February 26th, 2009, 4:12 pm
QuoteOriginally posted by: BullBearWhy I don't like to argue on market index valuation metrics: The S&P Gets Its Earnings Wrong S&P doesn't take weights into account!?The existing sum-of-dollar-earnings DOES take weighting into account. Jeremy Siegel's logic is so deeply flawed, that what he proposes would actually induce a weighting squared term in which money-making companies (whose share prices and market caps are, no doubt, higher) would effectively dominate his calculation of earnings. It's mathematical rose-coloured glasses.The proper way to look at this is to realize that each unit of the S&P 500 buys a fixed fraction of each of the underlying companies. Buy the right amount of S&P 500 index shares, and you'd own 100% of every company on the index. The weighting means you'd own 100% of the small companies (in a small $-fraction of the investment) as well as 100% of the big ones (in a large $-fraction of the investment), too. It also means that you'd accrue 100% of the dollar earnings and losses of each company. Thus the earning on the S&P are the sum of the dollar value of earning of the components and each share in S&P earns a piece of that.A second way to look at this is to imagine putting $100 into one share of a two-stock index in which one stock has 9X the market cap of the other. Imagine that both companies have a 1,000,000 shares and that the price of the big company is $90/share and the small company is $10 (i.e., market caps of $90 million and $10 million respectively). Then the big company reports earnings of $9 million and the little company reports losses of $9 million. Total earnings are zero. Your $100 investment just earned $9/sh from the big company, but lost $9/sh from the small one. The net gain to you to your share of the index is zero. Seigel's calculation would insist that you earned $7.2/share by double weighting the gains of the big company.QuoteOriginally posted by: BullBearThere's also a flaw when looking at historical market index metrics - the firms and index composition is always changing. Existent firms now are different from those on 1920... There's also a Darwinian evolution in the markets which preserve the stronger firms (Coca-Cola, Disney, McDonalds, Nike, Sony, Microsoft, Exxon Mobil, IBM) and get rid of weaker firms (lehman, bear, enron,...). Most robust and old firms are alive for decades... Their franchise value is unique so will be the franchise value of survivors.For example, a Bank able to survive and quickly expand its activity will boost its franchise value locally and overseas - "Solid as rock" type of marketing.The way to look at this is that the S&P 500 is really just a mutual fund with S&P being the fund manager in picking the investments. Yes, the fund does have turnover, but that does not mean that the fund/index doesn't have a consistent NAV that is defined over time (as long as the index turnover events are properly priced into the index).