兩周前的暴跌并沒有讓看好美國股市的人感到擔心。2月初，富國銀行、景順和瑞士銀行等機構的分析師和市場策略分析師在CNBC上預言，2018年美股將反彈，漲幅將達到甚至超過10%。

樂觀主義者一直都在用看似超級理性的觀點來進行解釋：暴跌主要是市場無序波動，而真正要緊的是美國經濟的光明前景。在他們看來，卓越的經濟指標就是注定要持續抬升股市的“基本面”，或者說根本力量。

實際上，他們把兩種“基本面”搞混了。經濟基本面確實很強，股市基本面卻很糟糕。

要弄清楚原因，最好的指南就是1999年的一篇文章《巴菲特先生和市場》（Mr. Buffett and the Market），1999年11月22日），它對巴菲特眼中的影響股價的因素進行了提煉，并解釋了當時這些因素為什么帶來了危險。這篇文章由《財富》雜志著名撰稿人卡羅爾·盧米斯于1999年巴菲特的兩次非正式發言編寫而成。

Last week’s big selloff isn’t fazing Wall Street’s bulls. In early February, analysts and market strategists from Wells Fargo, Invesco, and UBS, among several others, declared on CNBC that the stock market will rebound to post gains of 10% or more for 2018.

The optimists invariably present a seemingly super-rational explanation: The steep decline is mainly market noise, when what really matters is the strong outlook for America’s economy. In their view, the economy’s excellent metrics are the “fundamentals,” the essential forces, bound to keep propelling equities.

In reality, the bulls are confusing two kinds of “fundamentals.” The economic fundamentals are indeed strong. The stock market’s fundamentals are lousy.

To understand why, the best guide is a 1999 article that distilled Warren Buffett’s views on the factors that drive stock prices, and why they spelled danger at the time. The story (“Mr. Buffett and the Market,” Fortune 11/22/1999) was adapted by the great Fortune writer Carol Loomis from two informal talks that Buffett delivered that year.

巴菲特在這篇歷久彌新的文章中指出，在任何時候，預測未來回報率的兩個最有影響力的變量都是利率水平以及公司利潤和國民收入之比。對巴菲特來說，它們就是基本面，也是左右股價的一對引擎。在任何時間段開始的時候，如果利率極低而且公司利潤極高，隨后10年或者更長時間里的回報率就非常有可能表現慘淡。鑒于現在的情況恰恰如此，投資者應該對巴菲特的分析給予高度關注。

公司業績和利率能告訴我們什么

按照巴菲特的分析，引導華爾街的核心基本面因素，也就是強勁的經濟增長前景在預測股市走向時其實較不重要。他舉例說，如果目前公司利潤已經極高，今后其走勢就有可能落后，就算經濟增速超過平均水平。

現在看多股市的人仍在說，股價驟然下降和企業高度景氣之間發生了“割裂”，進而斷言這種情況毫無道理。他們預計股市和經濟很快就會并肩向前邁進。巴菲特則對另一種割裂現象提出了警告——一邊是超高的股價和泛濫的樂觀情緒，另一邊則是預示著艱難時期的基本面因素。

巴菲特用兩個17年比較了這些基本面因素的初始狀態怎樣影響后來的市場表現。第一個17年從1964年底到1981年，這期間的股價漲幅為零，給予股市沉重打擊的是利率的驚人攀升。

就像巴菲特在那篇文章里說的那樣：“利率越高，拉低股市的力量就越大。這是因為通過任何種類的投資，投資者要的回報率都直接和政府債券產生的無風險利率掛鉤?！?964年底美國10年期國債的收益率為4%，遠低于5%以上的歷史平均值。到了1981年底，這個數字達到15%，是期初的三倍以上。公司業績同樣表現很差，占GDP的比重從6.9%，也就是正常波動范圍（4%-6.5%）的高端下滑到3.5%。

雖然巴菲特沒有具體闡述國債收益率急劇上升的原因，但動力應該來自兩方面。首先是自動化趨勢拉低了其他所有資產的價格，從而造成“實際”利率，也就是剔除通脹因素后的10年期國債收益率上升。局勢良好時，“實際”利率會在資本需求增大時上行，此時經濟往往繁榮發展，公司則在其中看到了許多賺錢的機會。

但經濟前景非常不明朗時“實際”利率也會上升，此時緊張的債權人會要求用較大的緩沖作為今后局勢變差時的保險。當政府借款開始爭奪居民儲蓄時，私營部門的信貸成本就會增大。這兩種因素從20世紀70年代后期開始發揮作用，一直延續到1981年底。經濟在油價的壓迫下奮力抗爭，巨大的赤字讓聯邦政府借款不斷攀升。1981年，實際利率幾乎達到6%，在到今天為止的40多年里一直都是最高點。

然而，困擾股市的是另一只“怪物”，那就是肆虐的通脹，它源于歐佩克上漲了兩倍的油價。價格急升而且不可預測讓投資者如墜五里霧中。他們對美國的經濟領先位置失去了信心，并且擔心企業提高產品價格的速度趕不上成本增速?？傊咄涀尮善弊兊帽纫郧拔ｋU得多了。因此，投資者要股價大幅下降，以補償隨后可能變幻莫測的情況。

第二個17年從1982年初開始，到1998年底結束。在這個起點上，利率高得不可思議，公司利潤則格外低。對巴菲特來說，這絕對是最佳入手點，因為這兩個指標只需回到正常水平就能產生絕佳收益。情況也確實如此。這并不是因為GDP的快速增長，從而證明了巴菲特的觀點，即整體經濟增速不是影響股市回報率的關鍵因素。實際上，國民收入增幅遠低于上一個17年。但同樣的，在美聯儲主席保羅·沃爾克策動下，利率出現了歷史性下跌，從而讓股市收益達到最高水平。到1998年底，10年期國債收益率下滑了10個百分點，降至5%。公司利潤則強勁反彈，占國民收入的比重達到5.3%，上升了1.8個百分點，但原因并不是GDP迅猛上升，這只是因為企業利潤占國民收入的比例回到了正常水平。

黯淡預期成真

巴菲特上述分析的目的是在股市大漲之后評估1999年的前景。當時他預測說，1982年的超高債券收益率和低于平均水平的公司利潤帶來了巨大回報，同理，低于平均值的利率和出眾的公司業績預示著1999年的股市將表現一般。巴菲特指出，預期回報率達到兩位數的投資者可能會大失所望。他說：“這些日子股市投資者的預期太高了?！彼瑫r預測，包括分紅在內，這些人的全年收益率最多為6.5%。

巴菲特認為，上述兩大影響因素都不大可能改善，因為前一階段它們已經有了如此之好的表現。他說兩大基本面因素實際上都已經沒有空間了。從這個角度來說巴菲特錯了——到2015年底，10年期國債收益率從4.6%降到了2.2%，公司利潤占GDP的比重從5.2%升至8.8%。但兩種不利現象抵消了它們的作用。首先是經濟，在金融危機打擊之下，經濟年均增速只有區區2%。所以盡管企業利潤占國民收入的比重變大了，但主要原因是公司業績增長出色以及GDP增速較慢。

同時，市場遇到了反擊——巴菲特曾就此發出過警告，那就是估值大幅縮水。巴菲特看到1999年股票價格極高。投資者賦予公司利潤的估值倍數，或者說他們愿意接受的股價/利潤比高達33倍。巴菲特指出，投資者或許不愿意長期承擔如此之高的價格。后者確實也不愿意。從1999年到2015年，標普500指數的市盈率從33倍降至23.5倍，幾乎下挫30%。盡管這個階段（1999-2015年）的最后七年出現了一波大牛市，但股市整體表現甚至沒有達到巴菲特的預期。標普500指數年漲幅只有3%。因此，加上這個階段開始時1.5%的股息收益率，總回報率也僅為4.5%。

警示信號

那么就現階段而言，巴菲特的理論告訴了我們什么呢？預示未來低回報的基本因素要么跟2015年一樣處于極端水平，要么變的更為極端。10年期國債收益率去年雖然急劇上升，但目前仍只有2.84%。也就是說，“實際”利率更低，只有1%。公司利潤占國民收入的比重不斷上升，目前這個數字為9.4%，比長期平均值高50%。

1999年巴菲特是這樣說的：“如果今后10年或者17、20年一位投資者要在市場上大賺一筆，就必須滿足三個條件中的一個或多個，其中包括利率進一步下降和公司利潤占GDP的比重上升?！?

目前，巴菲特的兩大基本面指標比1999年夸張得多，而當時他就誤以為二者已經達到危險水平。利率已經開始上升，而且美聯儲還會繼續加息。由于失業率接近歷史最低點，公司終于開始提高工資以吸引就業者。因此，今后幾年勞動力在國民收入中的比例將上升，從而擠壓利潤。這樣的反轉意味著每股收益增速有可能落在GDP后面。

巴菲特所說的第三個條件讓股市前景更加黯淡，那就是動量成為主導因素。他警告說：“一旦進入牛市，一旦出現無論遵循什么樣的機制人人都能賺錢的情況，就會有一大群人被吸引進來，而且他們對利率和利潤都沒有反應，他們只看到一件事，那就是不炒股似乎是個錯誤。實際上，人們會把‘我不能坐失良機’這個因素置于左右市場的基本面因素之上?！?

動量過大

目前看來，動量確實掩蓋了基本面。按美國通用會計準則（GAAP）下過去四個季度的靜態利潤計算，市盈率仍處于25倍的高點，而且這個數字甚至極大地低估了股票的實際昂貴程度，原因是公司利潤正處于歷史高點，并有可能無法維持下去。

巴菲特在1999年的那篇文章中談到了整體股價水平，這種情況很少見。在最近的采訪中，他一直都拒絕說明自己是否認為股價過高。所以那篇文章絕不會代表巴菲特目前的想法。

但這篇啟蒙讀物提供了預測今后情況的工具?？磥磉@位投資傳奇從沒想過他關注的基本面因素可能不斷地測試新的極限。如今這些因素已經突破了他在19年前劃定的可能范圍，所以很難想象除了朝著不好的方向邁進外，利率和利潤還能往何處發展。

巴菲特當時預計1999年股市回報水平一般，但那個時候這些基本面因素遠沒有如今這么夸張?，F在，這些因素回歸正常水平就意味著今后的情況會比一般更差，而且要差得多。上周的暴跌就是這種局面可能已經到來的第一個信號。（財富中文網）

譯者：Charlie

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In that evergreen piece, Buffett explains that at any point in time, two variables are most influential in predicting future returns: The level of interest rates, and the ratio of corporate profits to national income. For Buffett, those are the fundamentals, the twin pistons that power stocks. If rates are extremely low, and profits extremely high, at the start of any period, it’s likely that returns over the next decade or more will most likely be poor. Since those are precisely today’s conditions, investors should pay close attention to Buffett’s analysis.

What earnings and rates tell us

According to Buffett’s analysis, the principal fundamental that guides Wall Street, the prospect of strong economic growth, is actually relatively unimportant in forecasting the performance of equities. For example, Buffett shows that if profits are already extremely elevated today, they’re likely to lag in the future, even if the economy expands at a brisker-than-average pace.

Today’s boosters keep talking about the “disconnect” between a sunny climate for business and the sudden drop in equity prices, and claim that it makes no sense. They predict that stocks and the economy will soon advance shoulder-to-shoulder. Buffett is warning about a different disconnect: Super-high prices and rampant optimism, versus fundamental factors signaling lean times ahead.

Buffett compares how these fundamentals at the start of each period shaped the market’s performance over two, seventeen-year spans. The first ran from the end of 1964 through 1981. In that entire interval, stock prices registered zero gains. The big hammer was an astounding jump in interest rates.

As Buffett states in the article, “The higher the rate, the greater the downward pull. That’s because the rates of return that investors need from any kind of investment are directly tied to the risk-free rate that they can earn from government securities.” The period dawned with the 10-year treasury yielding 4%, well below its historic average of 5%-plus. By late 1981, that number had more than tripled to 15%. Corporate profits also performed poorly, sagging from 6.9% of GDP–the high end of their normal range of 4% to 6.5%–to 3.5%.

Although Buffett doesn’t specify what caused the spike, that particular jump in yields came from two sources. The first is the trend that automatically lowers the prices of all other assets, a rise in the “real” rate, measured by 10-year Treasury yield adjusted for inflation. In good times, the “real” rate increases when demand for capital swells, typically when companies eye lots of profitable opportunities in a thriving economy.

But it can also jump when the economic outlook is highly uncertain, so that nervous creditors demand a big cushion as insurance against tough times ahead, and when heavy the government to borrowing competes for America’s savings, inflating the cost of credit for the private sector. Both of those forces were at work in the late 1970s through the end of our time frame, 1981: The economy was wrestling with crushing oil prices, and huge deficits swelled federal borrowing. In 1981, the real rate hit almost 6%, still the highest level in more than four decades.

But another bogeyman haunted equities: rampant inflation, ignited by OPEC’s tripling of oil prices. A climate of exploding, unpredictable prices shrouds investors in a thick fog. They lose confidence in the nation’s economic leadership, and fret that companies can’t raise prices as fast as costs. All told, high inflation makes stocks look a lot riskier, and hence investors demand steep discounts to compensate for a potentially treacherous times ahead.

The second period runs from the start of 1982 until the end of 1998. This time, the starting point was incredibly high rates, and extraordinarily low profits. For Buffett, that was the best of all places to launch, because a mere return to normal in both categories guaranteed super results. And super they were. The reason wasn’t an explosion in GDP, confirming Buffett’s view that overall growth isn’t a critical factor in equity returns. In fact, national income increased a lot less than it had in the previous period. Once again, it was an historic drop in rates, engineered by Fed Chairman Paul Volcker, that brought the biggest benefits. By late 1998, the 10-year yield had dropped by ten points, to 5%. Profits also rebounded strongly, gaining 1.8 points to reach 5.3% of national income. Profits thrived not because GDP growth was great, but simply because they reclaimed a normal share of national income.

A glum prediction comes true

The point of Buffett’s analysis was to assess the outlook in 1999, at the end of that fabulous run. Just as the gargantuan yields and sub-par earnings in 1982 heralded great returns to come, he predicted, below-average rates and excellent profits in 1999 foreshadowed mediocre times ahead. Buffett stated that investors who expected double-digit returns would be sorely disappointed. “Investors in stocks these days are expecting far too much,” Buffett said, forecasting that folks would reap total returns, including dividends, of a maximum of 6.5% a year.

Buffett predicted that the neither of the two big drivers was likely to improve from their current levels, because they’d already registered such favorable moves in the previous period. In effect, he said, the two big fundamentals had run out of room. In that sense, he was wrong: the 10-year Treasury yield fell from 4.6% to 2.2% by the end of 2015, and profits as a share of GDP rose from 5.2% to 8.8%. But a two headwinds blunted those forces. First, the economy, hammered by the financial crisis, grew at a pokey average of just 2% a year. So while profits took a bigger share of national income, it was largely because earnings grew at decent rates while GDP lagged.

But the markets suffered a counter-punch that Buffett warned about–a big contraction in valuations. Buffett observed that stocks were extremely pricey in 1999. The multiple investors award earnings, the amount they’re willing to pay for each dollar in profits, stood at a towering 33. Buffett noted that investors might not be willing to pay such rich prices for long. And they weren’t. From 1999 to 2015, the S&P 500’s P/E fell from 33 to 23.5, a decline of almost 30%. And even though the last seven years of that span (2009-15) included a roaring bull market, all told, stocks performed even worse than Buffett predicted. The S&P gained a mere 3% a year. So adding the 1.5% starting dividend yield, the total return came to just 4.5%.

Warning signals

So what does Buffett’s methodology tell us about the current period? The basics signaling low future returns either remain just as extreme as in 2015, or have only become more so. The 10-year yield has risen sharply in the last year, but still sits at 2.84%, putting the “real” rate at less than just 1%. Profits have kept claiming larger and larger shares of national income. The ratio of earnings to national income is now 9.4%, or 50% higher than its long-term average.

Listen to Buffett in 1999: “If an investor is to achieve juicy profits in the market over the next ten years or 17 or 20, one or more of three things must happen: (1) Interest rates must fall further. (2) Corporate profitability in relation to GDP must rise.”

Today, Buffett’s two main fundamentals are much more stretched than in 1999, when he wrongly believed that they’d reached the danger point. Rates are already rising, and more Fed rate hikes are on the way. With unemployment at near-record lows, companies are finally raising wages to attract workers. As a result, labor will get a bigger share of national income in the years to come, putting the squeeze on profits. That reversal means that earnings-per-share will likely lag GDP.

But the third factor Buffett mentioned further darkens the outlook. That when momentum takes charge. “Once a bull market gets underway,” he warns, “and once you reach the point where everybody has made money no matter what the system he or she followed, a crowd is attracted into the game that is responding not to interest rates and profits but simply to the fact that it seems a mistake to be out of stocks. In effect, people superimpose an I-can’t-miss-the-party factor on top of the fundamental factors that drive the market.”

Too much momentum

Today, it sure looks like momentum is swamping the fundamentals. The P/E, based on trailing GAAP earnings over the past four quarters, stands at a still lofty 25. Even that number greatly understates how expensive equities really are, since earnings are hovering at historic, probably unsustainable, highs.

The 1999 article marked one of the few times that Buffett discussed the general level of stock prices. In recent interviews, he’s declined to take a stance on whether stocks are excessively expensive. So in no way does this article purport to reflect current Buffett’s thinking.

But Buffett’s 1999 primer provides the tools for assessing what’s ahead. It appears that the legendary investor never imagined that his fundamentals could keep testing new limits. Now, that they’ve gone beyond the probable limits he outlined 19 years ago, it’s hard to imagine that rates and profits can go anywhere but in the wrong direction.

Buffett was predicting mediocre returns in 1999, when the fundamentals weren’t nearly this stretched. Now, a shift to normal would mean a future that’s worse than mediocre, a lot worse. The careening market is the first sign that the journey may have begun.