別指望下一個牛市很快到來

The smart advice during a falling stock market is not to panic. Selling out of panic often leads investors to miss out on the market recoveries that typically follow a drop, because it’s all but impossible to predict when such a recovery will begin.

在股市跳水期間，明智的建議是不要恐慌。下跌過後，市場往往會反彈，但因爲根本不可能預測這種反彈何時開始，出於恐慌而拋售，常常會導致投資者錯失良機。

But here is some different advice that’s worth hearing during a week like the current one: Don’t expect the next few decades of stock returns to be as good as the last few. Be prepared for a period in which market dips are not inevitably followed by bull markets that make the dips look like footnotes. Be prepared for something like mediocrity or even disappointment.

但在本週的情況下，有一些不同的建議值得聽聽：不要指望未來幾十年的股票收益會像過去幾十年那麼好。準備好面對一個新階段：在經歷市場跳水後，不一定會出現新一輪牛市，讓之前的跌勢顯得像是個腳註。準備好接受市場表現平庸，甚至令人失望的局面吧。

Why do I say this? Because stocks can’t boom forever. And the last 30 years, for all of their ups and downs, have mostly resembled one long boom. Stocks began rising in the early 1980s, and every market correction since then, including the financial crisis of 2007-8, has been quickly erased.

爲什麼說這些？因爲股市不可能永遠繁榮。而過去的30年，雖然有漲有跌，但總體上還是像一個長久的繁榮期。80年代初期，股市開始上漲。自那以後的每一次市場調整，包括2007年到2008年的金融危機，都很快被撫平了。

As a result, stock prices today remain historically expensive, even after the declines of recent weeks. Stocks are more highly valued than at any point from the 1940s through the mid-1990s, relative to long-term corporate earnings.

結果就是，即便經歷了最近幾周的下跌，當前的股價依然處於歷史高位。相對於企業的長期收益前景，現在股價被高估的程度，比40年代一直到90年代中期的任何一個時間點都更嚴重。

Why does this comparison matter? Stocks are effectively a claim on the future earnings of companies. When stocks are expensive relative to past earnings, it’s harder for future earnings to live up to investors’ hopes.

這種比較爲什麼重要？股票實際上代表着對企業未來收益的權利。如果股價相對於過去的收益顯得太貴，那麼未來的收益就更難達到投資者的期望。

It’s true that there are some reasons to believe stocks should be more expensive than in earlier decades. The low level of interest rates — which holds down corporate costs and makes competing investments less attractive, increasing demand for stocks — is one such reason. The absence of big wars involving many countries, and the resulting destruction, is another, as the economist John Campbell has noted. A third reason is workers’ relative lack of bargaining power these days, which holds down wages to the benefit of profits.

誠然，有一些原因會讓人們認爲，股價應該比早前幾十年高。低利率是其中的原因之一。低利率壓低了企業經營成本，降低了其他投資渠道的吸引力，同時提高了投資者對股票的需求。就像經濟學家約翰·坎貝爾(John Campbell)指出的那樣，另一個原因是沒有發生涉及很多國家因而會帶來巨大破壞的大規模戰爭。還有一個原因是，如今員工相對缺少議價權，這壓低了工資，對企業利潤有利。

But, as I argued in May 2014, when making the case that stocks looked expensive:

但就像我在去年5月提出，當時股價似乎過高時所說的：

… any argument that depends on the notion of a new paradigm is one you should treat with a healthy amount of skepticism. Those arguments are usually wrong. They were wrong in the 1920s, when the economist Irving Fisher coined the phrase “permanently high plateau” to describe stocks. They were wrong in 1999, when the book “Dow 36,000” appeared. They were wrong in 2007, on the eve of the financial crisis.

“……對於任何一種需要依靠新範式來論述的觀點，都應該持合理的懷疑態度。因爲那些論述通常都是錯的。1920年代，經濟學家歐文·費雪(Irving Fisher)創造出‘永久性的高地’(permanently high plateau)這個說法來描述股市時，就犯了這種錯誤。1999年，當《道指36000點》(Dow 36,000)一書面世時，其中的論述仍是錯的。到金融危機前夕的2007年，一些論述還是錯的。”

“You can always think of reasons of why now is different,” Mr. Shiller told me, when I called him recently to ask his view of today’s stock prices. “But maybe the mind is too creative in thinking of how it’s different.”

前不久，我打電話給席勒，問他對當前股價的看法。他對我說，“人們總有理由認爲今時不同以往。但在認爲如何不同這一點上，人的頭腦可能太有創造力了。”

Mr. Shiller, of course, is Robert Shiller, an economist and Nobel laureate whose data you see here. (I’ve updated the most recent data point.) It shows the value of the Standard & Poor’s 500 index relative to the earnings of the companies in that index over the prior 10 years. The 10-year span is long enough to include both economic good times and bad times.

席勒當然指的是經濟學家、諾貝爾獎得主羅伯特·J·席勒(Robert J. Shiller)，大家可以看看他提供的數據。（我更新了最新的數據點。）這些數據展示了標準普爾500指數相對於該指數所涵蓋公司之前10年的收益值。10年的跨度足夠包含經濟形勢好的時期和不好的時期。

That data series cannot predict the future of the stock market. Nothing can. But it has as good a record as any metric in pointing out when stocks seem broadly undervalued or overvalued. It soared above 30 in 1929 and above 40 in 1999. It fell below 10 in the late 1970s and early 1980s, before the long three-decade stock boom began.

這一系列數據無法預測股市的未來，也沒有什麼能夠預測未來。但這些數據作爲一種很好的度量標準，可以指出股票被普遍低估或高估的時期。這一數據在1929年飆升超過30，在1999年更是超過40。在20世紀70年代末80年代初降至10以下，此後進入了長達30年的股市繁榮發展時期。

The New York Times columnist Paul Krugman (another Nobel laureate) noted in his Monday column that the world is suffering from a savings glut. “We’re seeing,” he wrote, “what happens when too much money is chasing too few investment opportunities.” What happens are bubbles — in stocks, real estate and other assets, in the United States, Asia and elsewhere. Neil Irwin has described the phenomenon as “the everything bubble.”

《紐約時報》專欄作家保羅·克魯格曼（Paul Krugman，又一位諾貝爾獎獲得者）在週一發表的專欄文章中指出，整個世界因爲儲蓄過剩而受到損害。他寫道：“我們看到，當過多資金追逐過少的投資機會時會發生什麼。”那就是泡沫——美國、亞洲及其他地方的股市、房地產及其他資產都出現泡沫。尼爾·歐文( Neil Irwin)將這種現象描述爲“一切皆泡沫”。

The stock market is no longer in nearly as big or as bad of a bubble as it was in 1999 or 2007. But the market is still historically expensive. When it’s expensive, bad days happen more often than when it’s cheap.

股市泡沫不像1999年或2007年的泡沫那樣大，也沒那麼糟糕。但股市仍處於歷史高位。與股價較低時相比，股價較高的時候更常出現糟糕的日子。

None of this means you should start selling your stocks. They’re probably still the best long-term investment that exists. Just don’t get fooled into thinking that they’re always as good as they’ve been over the last generation.

這並不意味着你應該開始拋售股票。股票仍可能是現存的最佳長期投資方式。只是不要上當受騙，以爲股市會像過去幾十年一樣好。