It's a question that is always on investors' minds, but rarely more so than right now: Is the market overvalued?

　　这是一个一直萦绕在投资者心头的问题，但他们几乎没有哪个时候比现在更想知道这个问题的答案：市场被高估了吗？

　　Two heavyweights of financial analysis believe they hold the answer. Robert Shiller, the Yale University economist who correctly predicted the bursting of the stock market bubble in 2000 and the housing crash that started in 2006, has data that show stocks are pricey by historical measures. Getty Images.

　　金融分析界的两个重量级人物认为他们已经有了答案。耶鲁大学(Yale University)经济学家席勒(Robert Shiller)曾准确预测了2000年股市泡沫破裂以及始于2006年的楼市大跌，他的分析表明，从历史上的指标来衡量，目前的股价是昂贵的。

　　David Bianco, U.S. stock strategist at Bank of America Merrill Lynch, has been on a campaign to revise the good professor's math. Once he tweaks the calculations, he says, stocks look cheap.

　　而美国银行美林(Bank of America Merrill Lynch)的美国股票策略师比安科(David Bianco)则对这位知名教授的演算法进行了修正。他说他调整了计算方法后，发现目前的股价是便宜的。

　　The issue is more than a tempest in an academic teapot. The stock market has roared back from its March 2009 lows, doubling in value on an intraday basis in less than two years. But the last leg of the rally, which began last summer, largely has been driven by the Federal Reserve, whose policy of buying Treasury bonds to inflate asset values across the economy is set to end in June. Investors want to know whether stock prices are too frothy now, or whether they are reasonable estimations of companies' underlying earnings power.

　　这件事在学术界引发了轩然大波。股市从2009年3月份时的低点强力反弹，在不到两年的时间内单日市值上涨了一倍。但始于去年夏天的最近一轮涨势在很大程度上是受到了美联储(Federal Reserve)的推动，其购买美国国债的政策全面推高了资产价值，而这一政策将于6月份结束。投资者想知道目前的股价是否包含了大量泡沫，股价是否是公司潜在盈利能力的合理体现。

　　Which side you take—Mr. Shiller's or Mr. Bianco's—depends partly on whether you are more comfortable with the analysis of an academic who works far from Wall Street and whose job is to test theories, or a Wall Street strategist who is paid to track the market closely and bring in business. Bloomberg News.

　　耶鲁大学(Yale University)经济学家席勒(Robert Shiller)认为，目前的股价是昂贵的。你认同哪一方——席勒还是比安科——从某种程度上要取决于你是更乐于接受哪种观点：是一位远离华尔街工作、其任务就是对理论进行检验的学者的分析，还是一位依靠密切追踪市场来挣薪水的华尔街策略师的观点。

　　Mr. Shiller bases his analysis on a comparison of the value of the Standard & Poor's 500-stock index to its component companies' earnings results over time. Data of this kind don't predict when stocks will start to decline. They just show when stocks are getting expensive compared with their companies' earnings, a sign they could be headed for trouble sooner or later. Mr. Shiller keeps data going back to the late 19th century on his website, at www.econ.yale.edu/·shiller/data.htm.

　　席勒的分析是基于将一段时间中标普500(Standard & Poor's 500)股指成分股的市值与其收益数据所做的比较。这类数据并不是预测股票将于何时开始下跌。它们只是说明了相比公司的收益而言，这些股票是从什么时候变贵的，这也是预示公司可能早晚要出现麻烦的一种征兆。席勒分析的数据一直追溯到19世纪末，详细信息可参见他的网站www.econ.yale.edu/•shiller/data.htm。

　　The innovation of Mr. Shiller's system is that it is designed to avoid distortions from short-term profit swings. Most Wall Street analysts compare stock prices to the previous year's profits or to analysts' predictions of future profits. Mr. Shiller takes an average of corporate profits over the previous 10 years. Long favored by sophisticated investors, that method smoothes out the business cycle, producing a measure of sustainable corporate profit that investors sometimes call normalized profit.

　　席勒这一套分析体系的创新之处在于它避免了短期利润变化造成的失真。大部分华尔街分析师都会将股价与上一年的利润或是与分析师对于将来利润的预期做比较。而席勒则是对企业此前十年的利润进行了平均计算。这种为经验老道的投资者所长期青睐的方法消除了经济周期波动的影响，创造出一种能够衡量企业持续性利润的指标，这种利润有时被投资者称为常态化利润。

　　On that basis, Mr. Shiller's method shows the S&P 500 trading at 23 times profits, well above the historical average of 16. It doesn't necessarily mean stocks are about to fall; the S&P 500 went to a record 44 times earnings during the dot-com bubble before collapsing in 2000. But today's level isn't far from the peak of 27.5 hit before stocks fell during the financial crisis of 2007-09. At the 2009 bottom, it went down to 13 before quickly pushing higher again.

　　在此基础上，席勒的研究显示，标普500目前的市盈率为23倍，远高于16倍的历史平均水平。这并不一定意味着股市即将下跌；标普500在互联网泡沫时期的市盈率曾达到创纪录的44倍，随后在2000年遭遇重挫。但相比股市在2007-09年金融危机期间下跌之前创下的27.5倍的峰值，目前的水平与它相差并不远。2009年时标普500的市盈率曾降至13倍的低值，但很快它便再次升高。

　　Alternative Calculations 另一种计算方法

　　Mr. Bianco, who is bullish on stocks, says Prof. Shiller's measure is inaccurate, and the Wall Street strategist has taken his criticism public. Over the past year, he has written two reports offering alternative calculations.

　　看涨股市的比安科说，席勒教授的计算方法是不准确的，这位华尔街策略师还将他的评论公诸于众。他在过去一年中撰写了两份提供不同计算方法的报告。

　　Mr. Bianco says he began looking for ways to revise the Shiller numbers last year after a page-one article in The Wall Street Journal on the subject. Clients, he says, started using Mr. Shiller's data to contest his bullish thesis. Getty Images.

　　比安科说，在《华尔街日报》登载了一篇关于该问题的头版文章后，他从去年开始搜寻各种途径来修正席勒的数据。他说，客户们开始用席勒的数据来对他的看涨观点提出异议。

　　Mr. Bianco's massaging shows the S&P 500 trading currently at about 14.5 times his own calculation of 10-year profits, a much more attractive level than Mr. Shiller's 23 times profits.

　　比安科的分析显示，基于他自己对十年间盈利的计算，标普500目前的市盈率约为14.5倍，这一水平相比席勒得出的23倍的市盈率要有吸引力得多。

　　Clients call it the Bianco method vs. the Shiller method,Mr. Bianco says. 'People call it Wall Street vs. the universities, or the Ivory Tower vs. the Bank of America Tower.

　　比安科说，客户们说这是比安科方法与席勒方法的对比，人们说这是华尔街与大学的对比，或者象牙塔与美国银行大厦的对比。

　　Prof. Shiller says he hadn't paid attention to Mr. Bianco's work until recently, when The Journal inquired. Prof. Shiller reviewed his calculations in light of the criticism and says he likes his math the way he did it.

　　席勒教授说，直到最近当《华尔街日报》询问他时，他才注意到比安科的研究。席勒教授针对那些不同观点对他的计算进行了复查，他说他还是喜欢自己的计算方法。

　　'The basic analysis I have been presenting is right as is,' he said in an email message. Reuters.

　　美国银行美林的股票策略师比安科(David Bianco)看涨股市，他认为席勒教授的计算方法是不准确的。他在一封电子邮件中说，我所做的基本分析本来就是正确的。

　　Mr. Bianco doesn't dispute the usefulness of a 10-year average, an idea in line with the thinking of the founders of modern stock analysis, Benjamin Graham and David Dodd. He proposes to change Prof. Shiller's numbers in three ways, however, to remove what he thinks are distortions.

　　比安科并没有对十年平均值的有效性提出质疑，这种观点与现代股市分析的创始人格拉汉姆(Benjamin Graham)以及多德(David Dodd)的看法是一致的。然而，他建议通过三种方式来修正席勒教授的数据，以此消除他认为这其中存在的失真。

　　First, Mr. Bianco would adjust the way corporate earnings are calculated. Instead of the as-reported profits Mr. Shiller favors, he would use what analysts call operating earnings, which don't count some of the write-offs of the dot-com bust and the financial crisis. That change sharply boosts 10-year average earnings, making price/earnings ratios look less scary.

　　首先，比安科会调整公司收益的计算方式。他不会采用席勒所锺爱的收益报告中提到的公司利润，而是会选取被分析师称为营运收益的数据作为参考，这种收益不会计入互联网泡沫破裂以及金融危机期间出现的部分冲销。这种计算方式的调整大大提高了十年期平均收益，从而令市盈率看起来没有那么吓人了。

　　Second, he would change the historical data to which today's numbers are compared. He prefers to compare today's numbers only to data since 1960 or 1980, a period during which P/E ratios have been higher than in the past, making current levels look less extreme. If long-term data are used, he wouldn't count the decade following 1914, on the grounds that corporate profits were distorted by World War I more than by any other modern event, even the Great Depression. Throwing out that decade also makes past P/E ratios higher, so that today's look better.

　　其次，他会改变与今天的数据进行比较的历史数据。他只想把如今的数据与1960年或是1980年之后的数据做比较，这段时期内的市盈率水平要高于以往，这就使目前的市盈率看起来没有那么极端了。如果要采用更久之前的数据，他不会计入1914年之后的那个十年，因为企业利润由于第一次世界大战而出现的失真比现代其他任何重大事件（即便是“大萧条”）对它造成的影响都要大。剔除这个十年后，以往的市盈率再次升高，相比之下今天的市盈率也就更有吸引力了。

　　Finally, he would adjust earnings figures still higher, based on the fact that companies have been retaining a higher percentage of profits and paying lower dividends for decades. When companies retain and invest more profits, he says, earnings growth is faster and reported earnings don't fully reflect the ability of retained earnings to spur growth. He calls this the Equity Time Value Adjustment, or ETVA. Bloomberg News顿商学院(Wharton Business School)的塞格尔(Jeremy Siegel).

　　最后，他会进一步调高收益数据，因为数十年来企业一直支付着较低水平的派息，同时将更大比例的利润予以留存。他说，当企业将更多的利润留下用于进行投资时，收益会以更快的速度增长，收益报告中提到的收益无法完全反映出留存利润在刺激增长方面的能力。他将其称为股票的时间价值调整(Equity Time Value Adjustment，ETVA)。

　　The debate goes well beyond Mr. Bianco and Prof. Shiller. Prof. Shiller's old friend and sometime critic, Jeremy Siegel of the University of Pennsylvania's Wharton business school, is Mr. Bianco's former professor. Mr. Siegel is siding with his student and against his friend.

　　这场辩论所涉及的人远远不止比安科和席勒。席勒的故友、宾夕法尼亚大学(University of Pennsylvania)沃顿商学院(Wharton Business School)的塞格尔(Jeremy Siegel)曾是一名评论家，他过去是比安科的教授。这一次塞格尔站到了他的学生一边，与朋友意见相左。

　　Mr. Siegel agrees that earnings should be adjusted for the ETVA, and he also would massage earnings to remove some one-time charges. Earnings recorded at the depth of the financial crisis were highly unusual figures that shouldn't be used now to project future profits and stock values, he says.

　　塞格尔赞同对收益进行ETVA方面的调整，他在研究收益时还会剔除一些一次性的开支。他说，在金融危机最严重时期报告的收益数据具有非同一般的特殊性，它们不应被用来预测今后的利润以及股票价值。

　　'I respect Bob [Shiller] a lot. He is very thoughtful,' Prof. Siegel says. 'But to keep that once-in-a-75-year event in your data set, to say that is normal earnings, doesn't seem to be realistic.

　　塞格尔教授说，我很尊重席勒，他很善于思考，但将这种75年才发生一次的事情纳入你的数据组，将它看作是正常情况下的收益，显然是不可行的。

　　Dividends and Earnings 派息与收益

　　Robert Arnott, whose firm Research Affiliates LLC manages $73 billion from Newport Beach, Calif., has done his own research on one element of the debate: the relationship between dividends and earnings.

　　加州纽波特比奇(Newport Beach)Research Affiliates LLC公司董事长阿诺特(Robert Arnott)对这场辩论中的一个问题进行了自己的研究：派息与收益之间的关系。Research Affiliates LLC公司管理着730亿美元的资产。

　　He says his work shows it is a fallacy to think that lower dividends lead to faster earnings growth. Lower dividends come when companies are worried about the future or may be spending cash hoards on big acquisitions, which can hold down earnings growth, he says. Bloomberg News.

　　加州纽波特比奇(Newport Beach)Research Affiliates LLC公司董事长阿诺特(Robert Arnott)他说他的研究显示，认为低派息造成了收益高增长的观点是错误的。他说，当公司对未来感到担忧或是当公司也许是在利用现金储备进行大规模的收购时，派息水平会比较低，而这两种情况均会抑制收益增长。

　　'It is peculiar that this thesis keeps coming up year after year when it is so demonstrably wrong,' Mr. Arnott says.

　　阿诺特说，这种观点的错误之处是如此明显，它却仍然年复一年地甚嚣尘上，这种现象有些奇怪。

　　Like Mr. Shiller, Mr. Arnott also doesn't trust operating earnings and prefers to use those reported according to generally accepted accounting principles. Such numbers tend to show lower earnings results, but are more accurate, he says.

　　与席勒一样，阿诺特也不看重营运收益，他更愿意使用根据普遍接受的会计准则所得出的收益数据。他说，这种方法计算出的收益往往比较低，但却更加准确。

　　Mr. Arnott says he uses Shiller-style P/E calculations in his work. The figures helped persuade him to boost his U.S. stock exposure in 2009, when the 10-year P/E was low, and then cut his exposure when the P/E moved higher.

　　阿诺特说，他在工作中采用了席勒的市盈率计算法。依此得出的数字，他在2009年当十年期市盈率处于低位时增持了美国股市的股票，然后在市盈率上升时进行了减持。

　　Mr. Bianco says he will have to discuss this with Mr. Arnott. 'Rob is one of the best minds in the business,' Mr. Bianco says.

　　比安科说，他将和阿诺特讨论这个问题。他还说，阿诺特是这个行业里最聪明的人之一。

　　Just to show how small the financial world can be, Mr. Arnott also has had run-ins over the years with Prof. Siegel, Mr. Bianco's former professor.

　　这些年来，阿诺特也曾与比安科当年的教授塞格尔有过争论，这也从某个角度说明了金融界确实是个很小的圈子。

　　Mr. Siegel and Mr. Shiller, who despite their differences often vacation together, have been debating these issues since they were graduate students together, 40 years ago.

　　塞格尔和席勒从40年前他们在一起读研究生时就开始辩论这些问题，一直延续到现在。尽管二人之间存有分歧，他们却常常一起外出度假。

　　In the summer of 2009, walking on the beach on a barrier island near Atlantic City, N.J., they got so involved in a debate about stock-valuation methods that they briefly wandered away from their wives. They can accuse one another of errors without raising their voices, then thank each other for the critiques and talk about plans for the next vacation.

　　2009年夏天，塞格尔和席勒在新泽西州大西洋城(Atlantic City)附近一座堰洲岛的海滩上一边漫步一边对股价估值方法进行争论，他们太过忘我，以至于一度与妻子走散。他们指出对方的错误但却没有大喊大嚷，然后还互相感谢彼此提出的意见，接下来便开始畅谈起下一次度假计划了。

　　Mr. Shiller did his own calculation about the impact of declining dividends on earnings growth and concluded that it is marginal at best, not meriting any adjustment. He scoffs at the idea of eliminating the decade after World War I. He says he will think about Prof. Siegel's concern about the big write-offs.

　　关于派息减少对收益增长的影响，席勒按照自己的方式进行了计算，最后他认为这种影响充其量只是很有限的，不值得做任何调整。对于剔除一战后十年的想法，他也不以为然。他说他倒是会考虑塞格尔在大笔冲销这个问题上的疑虑。

　　But he is reluctant to make too many adjustments to data that he feels have painted a useful picture up to now.

　　但他不愿对数据做过多的修正，他觉得到目前为止这些数据对人们是有説明的。

　　'I think I should just keep it simple,' Mr. Shiller says.

　　席勒说，他觉得让这些数据保持原来的样子就好了。