市场抛盘是怎样发生的？
Stephen Gandel | 2014-08-29 16:43
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[译文]
“传染”系列文章：
【传染之一】比SARS更致命：蝙蝠病毒MERS是如何成为人类杀手的
【传染之五】从贾斯汀•比伯到数据学家，Twitter何以成为一门显学
Twitter, the social media company that uses a bird for its corporate logo, was the canary in the coal mine.
In early February, on a single day of trading, Twitter’s stock fell 24%, to $50 from $64. The impetus, such as it was, was that ad sales were not increasing as fast as expected. The rest of the market shrugged it off. The same day the Dow Jones industrial average rose 188 to a new high.
A little more than a month later, technology stocks were in free fall, tumbling faster with every whiff of bad news. Facebook shares, which had zoomed up 30% in late January and February, fell 20% in March and early April. Netflix’s shares lost $100.
And it wasn’t just technology stocks that were tanking. Electric car company Tesla’s shares fell as well. As did many biotechs.
What had changed? If anything, the economy seemed to have improved.
On April 10, the technology heavy Nasdaq Composite index lost 129 points, it’s worst single day drop in more than two and a half years—a swoon that sent the index below 4,000 for the first time in months. Many were saying this was just the beginning of a much larger selloff.
And then—just as quickly as it was—it wasn’t. Though Twitter shares haven’t fully recovered, technology stocks have been mostly rising ever since. Nasdaq is well above where it was before its April dive and is now just a tad off the nearly 14-year high it set on July 3.
以一只小鸟作为公司标识的社交传媒公司Twitter，就像是矿井下的金丝雀，最早中招。
2月初，Twitter股价在一个交易日内大跌24%，从64美元跌至50美元。触发因素是，广告销售增速不及预期。这并没有影响到其他市场投资者。当日，道琼斯工业平均指数上涨188点，创下新高。
1个多月后，科技股犹如自由落体，直线下跌，似乎每一个坏消息传闻都会加快这些股票的下跌速度。曾在1月底和2月份大涨30%的Facebook，在3月份和4月初下跌了20%。Netflix的股价跌了100美元。
而且，不只是科技股在下跌。电动汽车公司特斯拉（Tesla）的股价也在下跌。许多生物科技公司的股票亦是如此。
到底出现了什么状况？如果有什么变化的话，那就是美国经济似乎已有所改善。
4月10日，科技股权重较高的纳斯达克综合指数(Nasdaq Composite)下跌了129点，创下了超过两年半来最大单日下跌点数，并导致该指数多月来首次跌破4,000点。很多人表示，这只是更大规模抛盘的开始。
但更大规模的抛盘并未出现——抛盘消失之快，就像来时一样迅猛。虽然Twitter股价尚未完全恢复，但科技股自那以来大多呈现上涨。纳斯达克也已显著高于4月大跌前的水平，仅略低于7月3日创下的14年高点。
What changed, again? Beats me.
I have been reporting on the markets since 1996. In that time, I have covered two major market panics—the dot.com bust and the financial crisis—and dozens of minor ones. All of them have come without much warning, except in retrospect. Most go unnoticed until a good deal of the damage has already been done. And they disappear when you least expected it.
The changes in investor mood often happen in a flash—an infection of outlook that can seem as swift as an epidemic of flu. How and why does it happen? And are there similarities between such market mood swings and the way other things—pathogens, fashion trends, gossip—spread?
In a new Fortune series on Contagion, my colleagues and I set out to explore this murky process, investigating the spread of things as varied as the MERS-coV virus (here and here),M&A rumors, book sales and even a social phenomenon, ahem, such as “the selfie.”
情况又有什么改变吗？求拍醒。
我从1996年开始做市场报道。这期间，我报道过两次重大的市场恐慌（互联网泡沫破裂和上次金融危机），以及几十次较小的市场恐慌。所有这些来时都毫无征兆，除非我们回过头来看。大多数都没有被察觉，直到造成相当大的损伤。而且，它们会在你最意想不到的时候消失殆尽。
投资者的心境变化通常都在须臾之间，对未来的看法改变可以像流行感冒一样迅速传播。这是如何发生的？为什么？市场人气波动与病原体、时尚潮流和流言蜚语的传播方式是否存在相似之处？
在《财富》杂志最新的传染效应专题系列文章中，我和同事们将探索这一谜团般的过程，调查研究诸多事物的传播方式，比如中东呼吸综合征冠状病毒（MERS-coV）病毒、并购传言、图书销售甚至如“自拍”等社会现象。
In this same vein, I dove in to a mystery that has been stumping market-watchers and financial journalists—myself included—for ages: What causes investors to go from optimistic to nervous to panicked and back?
The answers that economists have come up with have been mostly unsatisfying or disproven. For a while, many settled on the notion that the market was essentially random, and left it at that.
But then came the financial crisis, which nearly swallowed the entire economy. Again the search for the causes of financial contagions, and how to contain them, became a hot topic.
The good news is that we have new research on what causes market panics, including a major study that came out in just the past few months. The bad news is this likely won’t end the debate either. Here’s what we know, and don’t know, about investors and their freak-outs.
Ask most professional investors and market strategists why stock panics happen and you will mostly get the same answer: Stock prices get too high.
“It’s called exhaustion in market terminology,” says Fred Hickey, who is the long-time editor of the widely followed newsletter, The High-Tech Strategist.
The realization that stocks were significantly overvalued appears to be what led to the 2000 tech bust. In March 2000, Barron’s published an article detailing how fast dotcom companies were running out of cash, and their stocks were overvalued. (Fun side note: Henry Blodget, then a technology stock analyst, said the math of the article was wrong.) That was long before anyone realized the accounting tricks that dot.com companies, and others, like Enron, were playing.
But we didn’t need to know any of that stuff to panic. In the three days following the Barron’s article, the Nasdaq index fell nearly 500 points, or 10%.
Hickey says the same was true in the run up to the financial crisis. Compare stocks to corporate sales or earnings, and it was clear that the market was overvalued in October 2007. And earlier this year, the prices of technology stocks, when you factor in their current growth projections, were trading at higher multiple of earnings than they were back in 2000.
“Why anyone would expect anything other than a decline is beyond me,” says Hickey.
Market value explanations, while a big deal for Wall Streeters, never really held much sway with financial professors. A little over a decade ago, Nobel Prize-winning economist Edward Prescott did a study of stock prices in 1929, before that year’s giant stock market crash. His conclusion: The market didn’t crash in 1929 because stocks were overvalued. If anything, based on what we know now, the market was cheap.
And while there were plenty of stocks that turned out to be worthless when the dotcom market crashed, others were cheap even at the peak. Amazon.com’s stock , for instance topped out at a split adjusted $89 in 2000. It now trades for $328.
Technology stocks, too, are just as expensive as they were a few months ago. Witness the phenomenon of hitcher app Uber, which was valued in early June at an eye-popping $17 billion—and that was before it raised another $1.2 billion in venture funding. That would make it worth more than Hertz (market capitalization: $13.5 billion), on virtual dotcom paper, that is. This all sounds bubbly, and yet, no one is running to sell.
The Barron’s article in 2000 was not the first time the financial media had raised the warning sign about tech stocks. Yet, for some reason that article stuck.
“The best we can say is that what causes selloffs is changes in investor sentiment,” says Harvard professor Malcolm Baker. “But why that change occurs we really don’t know.”
同样，我也试图深入挖掘多年来一直困扰市场观察人士和财经记者（包括我自己）的一个现象：是什么导致投资者从乐观转向焦虑，再转向恐慌，然后又重新乐观起来？
经济学家们给出的答案大多无法令人满意，或被证明是错误的。有一段时间，很多人接受这样的观点：市场本质上是随机的，仅此而已。
但随后发生了几乎吞噬整个美国经济的金融危机。寻找金融传染的起因以及如何控制传染，成为热门话题。
好消息是，我们对什么造成市场恐慌进行了新的研究，包括几个月前刚刚发布的一项重要研究。坏消息是，这些研究可能不会平息争论。关于投资者和他们的非理性反应，我们知道一些，但也有没搞明白的地方。
询问大多数专业投资者和市场策略师“为什么会发生市场恐慌”，你多数情况会得到同样的回答：股价涨得太高了。
“用市场术语讲，就是疲竭，”热门新闻简讯《高科技策略师》（The High-Tech Strategist）资深编辑弗雷德•希基说。
意识到股票被显著高估，看起来导致了2000年科技泡沫的破裂。2000年3月，《巴伦周刊》（Barron’s）发表了一篇文章详述互联网公司的现金流多么匮乏，以及它们的股票如何被高估。（旁注：时任科技股分析师亨利•布洛格特表示，这篇文章的数学计算是错误的。）当时还没有人意识到互联网企业以及安然（Enron）等其他公司正在玩什么会计把戏。
那时我们根本不需要知道这些东西便恐慌了。在《巴伦周刊》的文章发布后三天内，纳斯达克指数大跌近500点，跌幅10%。
希基说，金融危机前也是同样的状况。将股票与企业销售额或净利润相比，很显然2007年10月的市场估值已经过高了。今年早些时候，如果结合当期增长预期，科技股的市盈率也已超出2000年的水平。
“为什么人们认为绝不会下跌，这一点我不能理解，”希基表示。
虽然市场价值说对于华尔街人士意义重大，但从未对金融教授产生多少影响。十年多前，诺贝尔奖经济学奖得主爱德华•普雷斯科特在当年股市大崩盘前对1929年的股价进行了研究。他的结论是：1929年的股灾并不是因为股票估值过高。更何况，基于我们现在了解的信息，当时的股价还是挺便宜的。
而且，当互联网泡沫破灭时，有太多股票变得一文不名，但也有一些股票即使在市场峰值时期也非常便宜。比方说，亚马逊（Amazon.com）2000年的最高股价经拆股调整后为89美元。该股当前交易价格为328美元。
科技股同样也和几个月前一样昂贵。不妨来看看顺风车应用软件Uber。6月初，该公司估值达到惊人的170亿美元，这还是在该公司募得另外一笔12亿美元风险投资之前的估值。这使得该股的虚拟纸面价值超过了市值135亿美元的亨氏公司（Hertz）。这听上去全是泡沫，但没人着急卖。
2000年那篇《巴伦周刊》文章并非财经媒体首次对科技股发出警示。但不知什么原因，这篇文章引起了重视。
“我们最多只能说，是投资者的情绪变化导致了抛盘，”哈佛大学（Harvard）教授马科姆•贝克表示，“但我们真的不知道，投资者情绪为什么会变化。”
The theory that most economists prefer to explain stock market selloffs—probably because it comes from their own playbook—starts with supply and demand.
And it explains many market bubbles and busts in new technologies. Often when investors catch wind of an exciting new technology like, say, the Internet—or, today, social media and electric cars—there are few, if any, publicly traded companies.
Investors will pay up for those shares if it’s the only way to get in on the trend. But as more companies that do the same thing go public, or the ones that are public sell more shares, the supply of available shares increases. And as supply rises, prices tend to fall.
And there’s some evidence that’s what happened with technology stocks earlier this year. More than 45 technology companies went public in 2013 and early 2014, including Twitter, a number of other social media companies and game maker King.com , which owns the obsessively popular Candy Crush. What’s more, each one of these companies have lockup periods—a time, usually six months, after the IPO—after which insiders can sell shares. That increases the number of shares investors have to gobble up. The expiration of Twitter’s lockup alone made another 500 million shares of social media stock available for trading.
But that doesn’t explain market panics, like we saw earlier this year. If it were all about supply and demand, you would expect the selloffs to be measured and gradual. It also doesn’t explain why more shares of Twitter or King.com would cause investors to dump their holdings of Tesla or a slew of biotech companies, which also sold off in the spring. (In fact, Twitter’s lock-up expired in early May, when technology stocks were recovering.)
Nor does the theory really explain the financial crisis. Houses and mortgage bonds weren’t new, though the supply of both definitely increased during the run-up to the housing bust.
And neither the valuation explanation nor the supply argument really explains why this year’s tech stock selloff didn’t spread. Non-tech stocks, after all, look expensive, too. And many large companies have spent the past few years selling debt. Yet, outside of tech, stocks have continued to rise without barely a hiccup this year.
Tech investor Kevin Landis of Firsthand funds says part of the problem is there’s no obvious leader for tech investors to use as an anchor. A decade ago, investors would look to movements in Microsoft or Intel . But Microsoft has stumbled and Intel isn’t the powerhouse it used to be. “I don’t think you would say as Telsa goes, so goes the market,” says Landis. “Facebook is going to get there but it’s not there yet.”
That leads us to the latest theory of why market panics happen. In academic circles, at least, there’s been resurgence in interest in a theory that was popular a decade ago but had been dismissed by believers in efficient market theory. But now that the financial crisis has discredited the efficient market hypothesis—clearly houses and mortgage bonds were mispriced—alternative theories are making a comeback.
大多数经济学家倾向于从供需出发来解释股市抛盘，或许是因为这是他们最擅长的手法。
这可以解释发生在许多新技术身上的市场泡沫膨胀和破裂。通常情况下，当投资者刚刚注意到一项令人兴奋的新科技，比如互联网或者当今的社交传媒和电动汽车时，市场中鲜有已公开上市交易的此类公司。
如果这是赶上大好趋势的唯一途径，投资者会加码购入这些股票。但随着更多同类公司公开上市，或者已经上市的公司发售更多股票，可获得的股票供应增加。随着供应增加，价格会下跌。
今年早些时候的一些科技股走势提供了一些证据。2013年和2014年初有超过45家科技公司上市，其中包括Twitter、很多其他的社交传媒公司以及热门游戏《糖果传奇》（Candy Crush）的开发商King.com。这些公司每一家都在IPO后设有锁定期（通常为6个月），内部人士随后可以抛售股票。这增加了投资者必须吞下的股票数量。仅Twitter的锁定期满之后，就可以为市场增加5亿股社交传媒股票。
但这不能解释像我们今年早些时候看到的市场恐慌。如果这完全是因为供需关系，你可以预计抛售是有控制的，逐步的。这也不能解释为什么Twitter或King.com的流通股增加会促使投资者抛售特斯拉或一些生物科技公司，这些公司在今年春天也遭到抛售。（实际上，Twitter的锁定期在5月初到期，当时科技股正在恢复。）
这一理论也不能解释上一次金融危机。住房和抵押债券不是新鲜事物，尽管在房地产泡沫破裂前，两者的供应肯定增加了。
但是，无论是估值说，还是供应说，都不能解释为什么今年的科技股抛售没有蔓延。毕竟，非科技股看起来也很贵。而且，过去几年很多大公司一直在出售债券。不过，今年除科技股外，其他股票持续上涨，几乎没有任何停顿。
供职于Firsthand基金的科技投资者凯文•兰蒂斯表示，部分原因是没有明显的标杆股供科技投资者参照。十年前，投资者会看着微软(Microsoft)或英特尔(Intel)。如今，微软已步履蹒跚，英特尔也不复昔日雄风。“我想，你不会说什么只要特斯拉没事，市场就没事，”兰蒂斯表示，“Facebook将来会成为标杆，但现在还谈不上。”
这就涉及到了解释市场恐慌的最新理论。至少在学术圈，人们开始对于十年前流行的一种理论重拾兴趣，这种理论曾被效率市场理论的信奉者摒弃。但既然金融危机让人们对效率市场假设产生怀疑（住房和抵押债的定价显然有误），其他理论正在卷土重来。
The theory is called the consumption-based asset pricing model. Most theories of how the stock market works are based on the idea that investors sit around thinking about what Amazon or Apple might be worth. Together, by buying and selling stock, Mr. Market comes to some conclusion.
But the consumption-based asset pricing model says that’s not the way it works at all. Investors, actually, spend very little time thinking about whether a company’s shares are undervalued or overvalued. Instead, most investors make their investment decisions based on how much money they have and when they will spend it.
“Something that has no cash flows now but a lot in the future, I would be nervous about in a period when all of a sudden I think I am going to need cash,” says Chris Brightman, who leads the research and investment management team at investment advisor Research Affiliates.
In early January, Sydney Ludvigson, an economics professor at New York University who has been a defender of the consumption-based theories, co-authored a study that found that 75% of short-term stock price movements have to do with changes in investors appetite for risk.
It turns out the theory does a pretty good job of explaining the recent tech selloff. In the first quarter, corporate profits weren’t any worse than they were last year. But the economy did slow. And that may have made individuals slightly more concerned about how much cash they had, and whether they would need it sooner than they thought. And if you are worried about needing cash soon, you are probably less likely to invest in companies like Tesla and Twitter, which have a lot of potential, but are not yet producing profit, or a lot of it anyway. But you might still not be concerned about investing in Berkshire Hathaway or GE or Walmart .
By early April, the economy was starting to pick up again. And when it did technology stocks rebounded.
Nobel Prize-winner Prescott kind of agrees. He thinks the main thing that drives stock prices is tax policy. If investors think they are going to have to pay more in taxes, they will invest less. That doesn’t really explain why tech stocks dropped this year, or in 2008—but the point is, stock market panics are not only driven by a fear of stocks.
And that seems like a pretty good answer as to why people all of a sudden go running for Wall Street’s exits, at least for now.
这种理论就是基于消费的资产定价模型。大多数关于股市运作的理论都是基于这样一种观点：投资者会思考得出亚马逊(Amazon)或苹果(Apple)值多少钱。总体上，通过买卖股票，市场先生会有一些结论。
但基于消费的资产定价模型认为，这种方式不管用。事实上，投资者很少会花时间来考虑一家公司的股票是低估、还是高估。大多数投资者的投资决策是基于他们有多少钱，打算什么时候把它们花出去。
“如果我现在没有现金流，但未来会有很多，我会在一段时间内很紧张，担心突然之间我会需要现金，”投资咨询公司Research Affiliates投资与研究管理团队主管克里斯•布莱特曼表示。
纽约大学(New York University)的经济学教授西德尼•路德维金森一直支持基于消费的理论，1月初他参与撰写的一份研究报告发现，75%的短期股价变动与投资者的风险偏好变动有关。
这种理论在解释近期的科技股抛售时非常管用。第一季度，企业利润并不比上年同期差多少。但经济的确放缓了。而且，这可能让投资个体有点担心他们拥有多少现金，以及他们是否会早于预期就需要现金。如果你担心近期可能需要现金，你不太可能投资像特斯拉、Twitter这样的公司，虽然潜力巨大，但尚未产生利润或规模利润。但你可能不会担心投资伯克希尔-哈撒韦(Berkshire Hathaway)、通用电气(GE)或沃尔玛(Walmart)这类蓝筹股。
到4月初，美国经济开始再度提速。与此同时，科技股反弹。
诺贝尔奖得主普雷斯科特多少认同这种观点。他认为，股价的主要驱动因素是税收政策。如果投资者们认为他们将需要支付更多税款，他们会减少投资。这不能解释今年或2008年的科技股下跌，但关键是，造成股市恐慌的不只是对股票本身的担忧。
对于人们为什么突然之间从华尔街夺路而逃，这似乎是一个很好的答案，至少目前是这样。（财富中文网）
译者：早稻米
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