隨著道瓊斯指數收在20,000點以上，針對股價是否過高的永恒爭論也開始升溫。盡管我們都想向沃倫·巴菲特一樣，面對市場的趨勢不動如山，但大部分商業領袖實際上都做不到這一點。他們需要判斷何時適合回購股票，何時適合大規模或小規模獎勵員工認股權，或是在快退休時調整個人投資。所以讓我們直面問題：如今的股價是高還是低？最近發布的文章各執一詞，《華爾街日報》的一篇文章表示股價過低了，《財富》自己的編輯肖恩·塔利則在另一篇文章中稱股價太高。這里我也不賣關子，我贊同肖恩的觀點，因為我一直在做估值相關的工作，它讓我多年來受益匪淺。

股價太低的觀點，立足于一些可靠的事實。企業的利潤歷經兩年的跳水，開始攀升。唐納德·特朗普出人意料地當選總統，在11月9日以后也開始對市場產生影響。這昭示著華盛頓將出臺利于商業和增長的政策。更寬泛地說，經濟危機讓數百萬投資者在股市前裹足不前。而如今，隨著商業環境的回暖，許多投資者將回歸股市，流入的美金總體增加，將讓股價水漲船高。

根據這些可以觀察到的趨勢，這種論點似乎很有道理。但是肖恩對此并不贊同。相反，他詳細分析了數據，目前他們并沒有得到寬慰。標準普爾500指數（S&P 500）目前的市盈率為25.3，遠高于歷史平均值。然而，如果企業利潤能出現大幅增長，這一市盈率也可能是合情合理的，而且華爾街的分析師確實有這樣的預測。那么問題出在哪里呢？

問題在于，分析師往往會偏好他們的分析目標，高估了這些公司未來的利潤。研究公司FactSet表示，如果整體研究他們的利潤預報，你會發現預測的結果往往會高于公司的實際表現——大約7%。因此，未來利潤未必就會出現巨大提高。行情看漲可能意味著特定行業今年會有更好的表現，例如油價上漲會讓能源公司受益。但是油價上漲也會給其他公司帶來更高的成本，擠壓它們的利潤。

總之，我認為肖恩的觀點更具說服力。股價并不低。不過我也想起，市場即便是在不理性的情況下，也可能會向更加不理性的方向發展。艾倫·格林斯潘在1996年著名的“非理性繁榮”的演講中表示，在股票中賠本的投資者，即便是在牛市中，也會錯失80%股票上漲帶來的收益。

過去的情況也告訴我，類似道瓊斯指數2萬點這樣的里程碑沒有什么意義。因為一個指數接近某個值，并不代表它會達到那個值。畢竟，1965年12月道瓊斯指數達到969點時，投資者都對于它即將突破1,000點感到無比振奮。但它真正突破1,000點已經是七年以后了。 (財富中文網)

作者：Geoff Colvin

譯者：嚴匡正

As the Dow keeps not quite hitting 20,000, the eternal debate over the market’s priciness is heating up. And while we’d all like to maintain a Warren Buffett-like serenity toward the market’s direction, most business leaders, as a practical matter, cannot. They have to decide whether it’s a good or a bad time for a company to buy back stock, to award employee stock options in large quantities or small, or to adjust their personal investments as retirement approaches. So let’s face the question: Are stocks today cheap or expensive? Articles arguing opposite sides have just been published, one in the Wall Street Journal (stocks are cheap), the other by Fortune’s own Shawn Tully (stocks are expensive). So as not to keep you in suspense, I’m going with Shawn, as I always do in matters of valuation, a policy that has served me extremely well over many years.

The stocks-are-cheap argument proceeds from a few reassuring facts. Corporate profits are rising after having plunged over the past two years. The unexpected election of Donald Trump, which hadn’t been priced into the market until November 9, heralds an era of pro-business and pro-growth policy from Washington. More broadly, the financial crisis scared millions of investors away from stocks; now, as the business environment warms up, many of them will return, and the sheer volume of dollar inflow will push prices higher.

It’s a plausible argument based on observable trends. But Shawn has never favored that type of argument. Instead, he dissects the numbers, and right now they are not comforting. The S&P 500 is trading at a PE multiple of 25.3, which is far above historical averages. That multiple could be perfectly rational, however, if profits are about to explode, and Wall Street analysts are indeed predicting a strong rise. So what’s the problem?

The problem is that analysts tend to fall in love with the companies they analyze and overestimate future profits. If you aggregate their profit forecasts for the individual companies they cover, the result is usually way above the actual performance of the companies collectively – about seven percentage points above, says the FactSet research firm. The coming profit surge is by no means certain. The bulls like to note that certain industries should do much better this year, for example as rising oil prices benefit energy firms. But rising oil prices also impose higher costs and thus lower profits on other companies.

Bottom line, I think Shawn makes the more persuasive argument. Stocks are not cheap. But I also try to remember that even when the market is irrational, it’s perfectly capable of getting more irrational. Alan Greenspan notes that an investor who bailed out of stocks when he gave his famous “irrational exuberance” speech in 1996 would have missed 80% of the bull market’s gains.

I also try to remember that market milestones like Dow 20,000 are meaningless, and just because the index gets close to a round number doesn’t mean it’s about to hit that number. After all, investors got excited about Dow 1,000 when the index hit 969 in December 1965 – but it didn’t close above 1,000 for seven more years. Dow 20,000 could happen this afternoon, or years from now.