截至上周四，美國的牛市已經持續了八年。這比大部分專家預測的要長得多，也超出了華爾街幾個月前的預期。

今年僅過去兩個月，標普500（S&P 500）指數就已經達到甚至超過了華爾街許多頂尖公司預測的2017年全年目標。去年12月，彭博社（Bloomberg）調查了美國許多重量級證券公司的分析師，得出的預測是標普500指數會漲到2,340點——在今年年底。

而2017年至今，標普500指數已經上漲了超過6%，在3月1日最高曾達到2,396點，超過了預測數值。（之后指數略有下滑，上周三收盤時為2,363點。）特朗普總統上臺后，股指的增長已經持續了很長時間，這一段時期勢頭甚至更甚。去年11月起，因為特朗普承諾減輕企業稅負，放松政策，標普500指數的漲幅達到了11%。

整體來看，自2009月3月9日跌至當日最低值666點以來，標普500指數漲幅高達255%。根據摩根資產管理（J.P. Morgan Asset Management）的研究，歷史經驗來看，從低谷至高點，牛市的平均持續時間為四年半。

現在的問題是，這次牛市還將持續多久？已經有許多股市巨頭認為，股指恐怕即將迎來下跌。盡管今年頭兩個月漲勢強勁，但受訪的很多證券公司并未大幅調整，甚至根本沒有調整年終預測，這表明他們估計市場已經達到或接近今年的高點。

彭博社3月再次對證券公司進行了調查，他們對2017年的預測僅提高了10點至2,350點（低于股市現在的水平）。例如，巴克萊銀行（Barclays）就沒有調整他們2,400點的預期，不過他們把2017年的綜合每股收益從127美元上調到了130美元。瑞士信貸（Credit Suisse）和瑞士聯合銀行（UBS）去年12月預測今年年底的標普500指數為2,300點，他們依舊堅持自己對股指和每股收益率的推斷。

接受調查的機構中，也有一些對股市更為樂觀。德意志銀行（Deutsche Bank）把預測上調了200點至2,600點。美國銀行（Bank of America）也上調了150點，他們現在估計指數將在年底達到2,450點。

標普500指數是否繼續上揚，很大程度取決于特朗普經濟政策的效果。目前市場的熱情，建立在特朗普將成為企業利好的推測之上，不過最大的問題在于他想要推行的政策——包括廢除《可支付醫療法案》和稅法改革——能否獲得國會的通過。此外，稅法的改變最早也得到2018年才能看到效果，如果目前的牛市已經把希望寄托在這些改變上，恐怕用不了多久股市的漲速就將減緩。希望總比絕望好，不過某些情況下實用主義才能笑到最后。（財富中文網）

譯者：嚴匡正

The current bull market in stocks celebrates its 8th anniversary on Thursday. That run has lasted far longer than most experts predicted—and it has gone farther than Wall Street forecasters expected just a few months ago.

We’re barely two months into the year, and the S&P 500 has already reached or surpassed the full-year expected targets for 2017 set by many of Wall Street's top firms. In a Bloomberg survey from December of analysts from many of the nation’s heavy-hitting brokerages, the median forecast pegged the S&P 500 to be sitting at 2,340—at the end of this year.

The index has already surpassed that mark, rising more than 6% so far in 2017 to peak at 2,396 on March 1. (It has since retreated a bit, closing Wednesday at 2,363.) This has been the acceleration of a longer surge that took hold after President Trump was elected. Since November, investors have driven the S&P 500 up 11% on the back of Trump’s promises to cut corporate taxes and ease regulations.

Overall, the S&P 500 is up 255% since hitting an intraday low of 666 on March 9, 2009. Historically, the average bull market has lasted four-and-a-half years from trough to peak, according to research from J.P. Morgan Asset Management.

Now the question is how much longer the current bull will continue. And it appears many large players in the stock markets are already anticipating some sort of pullback relatively soon. Despite the sharp growth in the market in January and February, many of the brokerages surveyed haven’t adjusted their year-end forecast upward very much, if at all, indicating they feel the market is either at or very near its peak for the year.

The median forecast for 2017 rose only 10 points, to 2,350 (below the market's current level), when Bloomberg surveyed analysts again in March. Barclays, for example, hasn’t budged off its target of 2,400, though it has moved its combined 2017 earnings per share estimate for the companies in the index up from $127 to $130. Credit Suisse and UBS, which both forecast 2,300 in December, have not changed their predictions for the index’s level or earnings per share.

There are some more optimistic views among those surveyed. Deutsche Bank has raised its forecast 200 points, to 2,600, and Bank of America has added 150 points to its prediction, bringing its estimate to 2,450.

Whether or not the S&P 500 continues its rise is likely to heavily depend on the impact of Trump’s economic agenda. The market’s run has been fueled by speculation that Trump will be a boon for business, but the biggest elements of his policy wish list—including the repeal of the Affordable Care Act and his tax reforms—have uncertain prospects in Congress. What's more, any changes in tax law wouldn’t go into effect until 2018 at the earliest; if the current bull run is factoring in those changes already, then a slowdown in the stock surge may not be far away. Hope is better than despair, but at some point pragmatism may win out.