激活市场先生:采取恰当的心理态度
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2015 年 2 月 10 日
激活市场先生:采取正确的心理态度
Animating Mr. Market Adopting a Proper Psychological Attitude February 10, 2015
Authors
Authors
迈克尔·J·莫布森(Michael J. Mauboussin) [email protected]
Michael J. Mauboussin [email protected]
丹·卡拉汉,特许金融分析师(CFA),[email protected]
Dan Callahan, CFA [email protected]
“如果你想在华尔街赚钱,你必须拥有正确的心理状态。你必须从永恒的视角来看待事物。”——本·格雷厄姆,《本·格雷厄姆的遗产》
“If you want to make money on Wall Street, you must have the proper psychological attitude. You must look at things under the aspect of eternity.” Ben Graham The Legacy of Ben Graham
要想成为一名主动投资者,你必须相信市场的无效性才能获得机会,同时也要相信市场的有效性,才能使这些机会转化为利润。
To be an active investor, you must believe in market inefficiency to get opportunities and in market efficiency for those opportunities to turn into profits.
市场先生这个比喻非常有力,因为它把一个抽象的概念变得具体,引导我们用恰当的方式去思考市场。
The Mr. Market metaphor is very powerful because it makes an abstract idea concrete, encouraging an appropriate way to think about markets.
一个让市场先生更生动的方式,是想想群体智慧。
One way to animate Mr. Market is to consider the wisdom of crowds.
关键在于,人群在某些条件下是明智的,而一旦这些条件被违反,就会变得疯狂。
What’s key is that crowds are wise under some conditions and mad when any of those conditions are violated.
因社会原因以及技术原因都可能导致的多样性崩塌,会引发极端情况。
Diversity breakdowns, which can happen for sociological as well as technical reasons, lead to extremes.
寻找那些因一致预期而导致定价错误、从而有机会赚钱的案例。
Look for cases where uniform belief has led to a mispricing of expectations and hence a way to make money.
恰当的心理态度
The Proper Psychological Attitude
本杰明·格雷厄姆,这位著名的投资家兼备受尊崇的导师,在哥伦比亚商学院开课的第一句话就是:“如果你想在华尔街赚钱,就必须具备正确的心理态度。”
Ben Graham, a renowned investor and revered teacher, opened his course at Columbia Business School by saying, “If you want to make money on Wall Street, you must have the proper psychological attitude.”
他引用了哲学家巴鲁赫·斯宾诺莎《伦理学》中的一段话,接着说:“你必须从永恒的角度来看待事物。”大意翻译过来就是,你需要采取一种客观的视角。
Referring to a passage in Ethics by the philosopher Baruch Spinoza, he added, “You must look at things under the aspect of eternity.” Translated loosely, this means you need to take an objective point of view.1
沃伦·巴菲特——伯克希尔·哈撒韦的董事长兼首席执行官,也是格雷厄姆最著名的学生——建议你需要阅读三个章节才能塑造出那种态度²:
Warren Buffett, chairman and chief executive officer of Berkshire Hathaway and Graham’s most famous student, suggests you need to read three chapters in order to shape that attitude2:
第八章 本·格雷厄姆《聪明的投资者》(“投资者与市场波动”)
Chapter 8 from The Intelligent Investor by Ben Graham (“The Investor and Market Fluctuations”);
第二十章 来自《聪明的投资者》(“‘安全边际’作为投资的核心概念”);
Chapter 20 from The Intelligent Investor (“‘Margin of Safety’ as The Central Concept of Investment”);
以下是《就业、利息和货币通论》第 12 章(“长期预期状态”)的译文:
我们建立一个投资价值理论时,最终依赖的并非市场价格,而是我们对未来收益的预期。这些预期的基础,是我们对长期趋势的估计。而长期预期,在相当程度上,并不取决于我们所能掌握的最可能结果,而取决于我们对这种预期本身的信心——这种信心是我们对自身判断可靠程度的衡量。换言之,我们对某个预期结果的心理确定性程度,会显著影响我们的行为。在充满不确定性的世界里,我们往往不得不依赖两种方法:一是假定现状会持续下去,除非我们有明确理由相信它会改变;二是将大多数人的意见或行为当作自己的判断准绳。从长期来看,我们所能依赖的,既不是传统智慧,也不是精确计算,而是我们对未来这种近乎无知的判断——即凯恩斯所说的“动物精神”。
Chapter 12 from The General Theory of Employment, Interest and Money by John Maynard Keynes (“The State of Long-Term Expectation”).
本次讨论的重点是第 8 章,特别 是 本杰明·格雷厄姆 关于 市场先生 的寓言。我们有三个目标:
The focus of this discussion is chapter 8, and in particular Ben Graham’s parable of Mr. Market. We have three goals:
1. 论证市场先生这个比喻仍然是思考市场的一种有力方式;
1. Argue that the Mr. Market metaphor remains a powerful way to think about markets;
2. 引入一些理念——其中有些在格雷厄姆提出这个比喻时尚未充分发展——来帮助激活这个概念;
2. Introduce a handful of ideas, some of which were not fully developed when Graham introduced the metaphor, to help animate the concept;
3. 提供一些具体的方法,让你思考如何利用市场先生为你服务。
3. Provide some concrete ways to think about using Mr. Market to your benefit.
格雷厄姆在第 8 章开篇指出,股票会波动(这当然没错),而市场参与者有两种方式能从这些波动中获利。第一种是“择时”,即试图预测股市走向。第二种是“定价”,即买入价格低于其价值的股票,再以高于其价值的价格卖出。
Graham opens chapter 8 by noting that stocks fluctuate (of course) and that there are two ways that a participant in the market can profit from those swings. The first is “timing,” the endeavor to anticipate the action of the stock market. The second is “pricing,” buying stocks for less than they are worth and selling them for more than they are worth.
他紧接着补充说,择时对投资者行不通,那是投机者的领地。尽管媒体上评论家层出不穷,但专家在复杂领域预测能力之差的证据确凿且记录翔实。这方面最出色的研究来自宾夕法尼亚大学心理学教授菲利普·泰特洛克,他耗费 20 多年追踪了数百位专家在政治、经济、社会领域的预测。他的结论对格雷厄姆而言毫不意外:“……许多权威人士的表现并不比随机猜测强多少,他们过度自信,且不愿根据新证据改变立场。”
He adds quickly that timing doesn’t work for an investor and remains the purview of the speculator.3 Notwithstanding the parade of commentators in the media, the evidence that experts predict poorly in complex domains is quite clear and well documented. The best work in this area is by Philip Tetlock, a professor of psychology at the University of Pennsylvania, who studied the predictions of hundreds of experts making political, economic, and social forecasts over 20 years. His conclusions would have come as no surprise to Graham: “. . . many pundits were hardpressed to do better than chance, were overconfident, and were reluctant to change their minds in response to new evidence.”4
格雷厄姆接着指出,聪明的投资者思考市场的一个有用方式,就是通过市场先生的寓言。在这个版本的寓言中,你持有一家私营公司的一小部分股份,成本是 1000 美元(按今天的币值大约相当于 1 万美元)。你的一位合伙人是个乐于助人的家伙,名叫市场先生。
Graham goes on to argue that a useful way for an intelligent investor to think about the market is through the parable of Mr. Market. In Graham’s version, you own a small stake in a private company that costs you $1,000 (approximately $10,000 in today’s dollars). One of your partners is an obliging fellow named Mr.
每天,市场先生都会告诉你,他认为你的持股价值是多少,而且还会报出一个价格,他愿意按这个价格买断你的股份,或者卖给你更多股份。
Market who tells you, every day, what he thinks your stake is worth and, further, offers a price at which he’s willing to buy you out or offer you an additional interest.
在讲述市场先生寓言时,沃伦·巴菲特补充说,市场先生患有“无法治愈的情绪问题”。5 有时他兴高采烈,只看得到有利的结果,因此报出非常高的买卖价格。另一些时候他又郁郁寡欢,只看到负面的结果,报出非常低的买卖价格。
In his telling of the Mr. Market parable, Warren Buffett adds that Mr. Market has “incurable emotional problems.”5 Sometimes he is euphoric and sees only favorable outcomes and hence names a very high buy-sell price. Other times he is depressed and sees only negative outcomes and provides a very low buy-sell price.
但事实上,市场先生绝大多数时候状态正常,报价也合情合理。
But, in fact, there are plenty of days when Mr. Market is doing fine and his price is sensible.
2013 年,诺贝尔经济学奖颁给了三个人。其中一位获奖者是耶鲁大学教授罗伯特·席勒(Robert Shiller),他以证明市场无效而闻名。另一位是芝加哥大学教授尤金·法玛(Eugene Fama),他以倡导市场有效著称。(第三位是同样来自芝加哥大学的拉尔斯·汉森(Lars Hansen)。)
In 2013, the Nobel Prize in economics went to three men. One of the recipients, Robert Shiller, is a professor at Yale University known for showing that markets are inefficient. Another was Eugene Fama, a professor at the University of Chicago known for his advocacy of market efficiency. (The third was Lars Hansen, also at the University of Chicago.)
这就引出了第一个值得强调的观点:要做一名主动型投资者,你必须相信市场既无效率又有效率。换句话说,你必须认为席勒和法马都是对的——只是不在同一时刻成立。
This leads to the first point worth stressing: to be an active investor, you must believe in both inefficiency and efficiency. In other words, you have to think that both Shiller and Fama are right―just not at the same time.
自然,如果市场完全有效,就没有理由试图通过主动管理来战胜它。
Naturally, if markets are perfectly efficient there’s no reason to try to beat them through active management.
但同样正确的是,如果你认为市场始终无效,就没有理由试图通过主动管理来跑赢市场。因为即使你足够精明,能以 50 美分买到价值 1 美元的东西,在一个永远无效的市场里,也没有理由相信价格和价值会最终趋同。
But it’s also true that there’s no reason to try to beat the market through active management if you think markets are always inefficient. That’s because even if you are savvy enough to buy a dollar for fifty cents, there’s no reason to believe that the price and value will ever converge in a perpetually inefficient market.
格雷厄姆说过一句格言,但他从未正式写过:“短期来看,市场是一台投票机,长期来看则是一台称重机。”这句引文有时被当作短期主义的证据。但我们认为,这是对这条信息的误读。更好的理解是,市场的股票定价有时会出错,但价格与价值最终会在将来趋同。
A maxim that Graham spoke, but never wrote formally, is, “In the short run, the market is a voting machine but in the long run it is a weighing machine.” This quotation is sometimes taken as evidence of short-termism. We believe this is a misreading of the message. A better interpretation is that sometimes the market prices stocks incorrectly, but that price and value ultimately converge in the future.6
内在价值等于未来自由现金流的现值。由于未来不可预知,你可以把内在价值理解为一个区间。确实,价格经常落在这个区间内——市场先生多数时候是基本正确的。但有时市场先生会变得亢奋,报出一个非常高的买卖价格;而另一些时候他又情绪低落,报出一个很低的价格。参见图 1。
Intrinsic value equals the present value of future free cash flow. Because the future is unknowable, you might think of intrinsic value as a range. Indeed, prices are often in that range―Mr. Market is getting things mostly right. But there are times when Mr. Market becomes manic and names a very high buy-sell price, and other times when he’s depressed and names a low price. See exhibit 1.
附录 1:市场先生走向极端
Exhibit 1: Mr. Market Goes to Extremes
市场先生的狂躁区
Mr. Market manic zone
Intrinsic value
Intrinsic value
市场先生的抑郁地带
Mr. Market depressed zone
来源:瑞士信贷。
Source: Credit Suisse.
格雷厄姆的观点——后面我们还会再谈——是:聪明的投资者把市场先生的波动当作可以利用的信息,而不是被价格走势牵着走。当然,这在心理上极难做到。
Graham’s point, to which we will return, is that the intelligent investor uses Mr. Market’s swings as information that he or she can take advantage of, rather than being influenced by the price action. This, of course, is very difficult to do psychologically.
在结束这部分讨论之前,还有两点值得补充。首先,构建一个经风险调整后收益率能超越标普 500 指数或任何相关基准的资产组合,并非易事。而且随着时间的推移,难度还在不断加大。我们可以通过超额收益的标准差来证明这一点。图表 2 展示了 1963 年至 2014 年间美国大型共同基金五年平均超额收益率的标准差。如果你把超额收益率想象成钟形分布——虽然不完全准确,但相差不远,仍有参考价值——那么这条钟形曲线在过去几十年里变得越来越窄。实际上,2014 年的数值创下了新低。
Before leaving this part of the discussion, two additional points are worth making. The first is that it is not easy to generate returns in a portfolio, adjusted for risk, that exceed the S&P 500 or any relevant benchmark. And it has become more difficult over time. One way we can show this is through the standard deviation of excess returns. Exhibit 2 shows the five-year average standard deviation of excess returns for U.S. large capitalization mutual funds from 1963 through 2014. If you imagine excess returns as a bell-shaped distribution—which is not true but not so far off to be useless—then the bell has gotten skinnier over the decades. Indeed, the 2014 figure set a new low mark.
图 2:美国大盘基金超额收益率的标准差,1967–2014 年 18%
Exhibit 2: Standard Deviation of Excess Returns for U.S. Large Capitalization Funds, 1967-2014 18%
超额收益的标准差
Standard Deviation of Excess Returns
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
| 年份 | 基金数量 |
|---|---|
| 16% | |
| 14% | |
| 12% | |
| 10% | |
| 8% | |
| 6% | |
| 4% | |
| 1967 | 69 |
| 1970 | 120 |
| 1973 | 142 |
| 1976 | 187 |
| 1978 | 311 |
| 1981 | 562 |
| 1984 | 979 |
| 1987 | 1,328 |
| 1989 | 1,070 |
| 1992 | |
| 1995 | |
| 1998 | |
| 2000 | |
| 2003 | |
| 2006 | |
| 2009 | |
| 2011 | |
| 2014 |
16% 14% 12% 10% 8% 6% 4% 1967 1970 1973 1976 1978 1981 1984 1987 1989 1992 1995 1998 2000 2003 2006 2009 2011 2014 Number of funds 69 120 142 187 311 562 979 1,328 1,070
数据来源:Markov Processes International、晨星(Morningstar)及瑞士信贷。
Source: Markov Processes International, Morningstar, and Credit Suisse.
注:展示的是超额收益标准差五年期平均值。
Note: Shows five-year average of standard deviation of excess returns.
第二,价值投资确实有效。图 3 展示了自 1927 年以来价值股与成长股的表现对比。该图根据市净率,呈现了昂贵股票组合与廉价股票组合之间复合年增长率的差异。现在有理由追问:这 250 个基点的价值溢价,究竟是源于风险因素还是行为偏差?证据的天平倾向于行为解释更符合事实。这一切与市场先生的理论高度吻合。7
Second, value investing works. Exhibit 3 shows value versus growth going back to 1927. The exhibit displays the difference in the compound annual growth rate (CAGR) for a portfolio of expensive stocks versus one of cheap stocks, based on the ratio of price to book value. Now it’s reasonable to ask whether the value premium of 250 basis points is the result of risk or behavioral issues. The balance of the evidence suggests that the behavioral explanation better fits the facts. This is all very consistent with Mr. Market. 7
表 3:价值溢价,1927-2014 年
Exhibit 3: The Value Premium, 1927-2014
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
| 年化增长率 | |||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 100,000 | |||||||||||||||||||||||||||||
| 12.8% | |||||||||||||||||||||||||||||
| 价值 | |||||||||||||||||||||||||||||
| 10,000 | |||||||||||||||||||||||||||||
| 10.3% | |||||||||||||||||||||||||||||
| 1,000 | |||||||||||||||||||||||||||||
| 美元 | |||||||||||||||||||||||||||||
| 增长 | |||||||||||||||||||||||||||||
| 100 | |||||||||||||||||||||||||||||
| 10 | |||||||||||||||||||||||||||||
| 1 | |||||||||||||||||||||||||||||
| 0 1927 | 1930 | 1933 | 1936 | 1939 | 1942 | 1945 | 1948 | 1951 | 1954 | 1957 | 1960 | 1963 | 1966 | 1969 | 1972 | 1975 | 1978 | 1981 | 1984 | 1987 | 1990 | 1993 | 1996 | 1999 | 2002 | 2005 | 2008 | 2011 | 2014 |
CAGR 100,000 12.8% Value 10,000 10.3% 1,000 Dollars Growth 100 10 1 0 1927 1930 1933 1936 1939 1942 1945 1948 1951 1954 1957 1960 1963 1966 1969 1972 1975 1978 1981 1984 1987 1990 1993 1996 1999 2002 2005 2008 2011 2014
资料来源:肯尼斯·R·弗伦奇(Kenneth R. French),详见 http://mba.tuck.dartmouth.edu/pages/faculty/ken.french/。
Source: Kenneth R. French, see http://mba.tuck.dartmouth.edu/pages/faculty/ken.french/.
注:数据来自“规模与账面市值比构成的四组投资组合”系列;年度系列采用“大”股票的平均等权回报率;CAGR = 复合年增长率。
Note: From series “4 Portfolios Formed on Size and Book-to-Market”; Annual series uses average equal-weighted returns for “big” stocks; CAGR = compound annual growth rate.
群体的智慧与疯狂
The Wisdom and Madness of Crowds
那现在咱们就挽起袖子,聊聊解释市场有效性的各种理论。开始之前,得先承认:任何站得住脚的理论都必须容纳两个现实。第一,市场很难跑赢。第二,市场会周期性地在涨跌两端冲向极端。
So now let’s roll up our sleeves and ask about the various theories to explain market efficiency. Going in, we need to acknowledge that any satisfactory theory has to accommodate two realities. First, markets are hard to beat. Second, markets periodically zoom to excesses on the upside and downside.
解释市场效率有三种基本理论。8 第一种假设投资者是理性的,这意味着他们会根据预期效用理论做出规范上可接受的选择,并依据新信息正确地更新自己的看法。
There are three basic theories to explain market efficiency.8 The first is to assume that investors are rational, which means that they make normatively acceptable choices based on expected utility theory and correctly update their views based on new information.
第二种假设是,存在一小群理性投资者,他们利用套利来消除价格错误。我们可以放松“所有投资者都是理性的”这一假设,转而依赖这少数几个人来确保火车准点运行、邮件准时送达。
The second is to assume a small set of rational investors who use arbitrage to remove pricing errors. We can relax the assumption that all investors are rational and rely on a handful of them to make sure the trains run on time and the mail is delivered.
最后一种理论是群体智慧,即一群具有多样性的个体能够得出一个有效的价格。我们将论证,这个理论最贴合市场先生的故事,但在深入细节之前,我们先快速审视一下理性经济人和套利。
The final theory is the wisdom of crowds, the idea that a group of diverse individuals can come up with an efficient price. We are going to argue that this fits the Mr. Market story the best, but before we get to those details, let’s look very quickly at rational agents and arbitrage.
如今还顽固信奉理性人假设的人已经寥寥无几。不过,金融经济学家在描述和讨论市场时,仍然普遍沿用这一框架。在关于市场是否理性的辩论中,加州大学伯克利分校教授马克·鲁宾斯坦站在肯定一方。他在阐述自己观点的论文中这样写道(原文的斜体和下划线即为强调):⁹
There are few remaining hard-core believers in rational agents. But it is still a common way for financial economists to describe and discuss markets. In a debate about whether markets are rational, Mark Rubinstein, a professor at the University of California, Berkeley, took the affirmative side. Here’s what he said in the paper that outlined his case (the emphasis in italics and underlining is original):9
我去金融经济学家培训学校时,被教导的是“首要指令”……
When I went to financial economist training school, I was taught The Prime Directive . . .
无论我还做什么,我都应当遵循“首要指令”:
Whatever else I would do, I should follow The Prime Directive:
只用理性模型来解释资产价格。只有当所有尝试都失败后,才转而归因于投资者的非理性行为。
Explain asset prices by rational models. Only if all attempts fail, resort to irrational investor behavior.
这份文件本身相当有趣,值得一读。它并不像这段摘录所显示的那么片面。但它确实反映了一代金融经济学家的训练和态度。
The paper itself is quite interesting, and worth a read. It’s not as one-sided as this excerpt suggests. But it does reflect the training and attitude of a generation of financial economists.
理性人理论其实并不难推翻。首先,我们知道投资者的计算能力和理性程度远不足以用规范可接受的方式行事;其次,我们也知道市场会以理性难以解释的方式陷入疯狂。
Now it’s not all that hard to dismiss the rational agent theory. First, we know that investors have nowhere near the computational ability or rationality to act in a normatively acceptable way, and we also know that markets go haywire in a fashion that rationality has a hard time explaining.
后者的一个明显例子是 1987 年的股市崩盘——当天道琼斯工业平均指数暴跌 22.6%。按照传统理论,这种事件发生的概率微乎其微,任何理性的解释都令人难以置信。¹⁰ 例如,当被问及此事时,尤金·法玛说:“我认为 1987 年的崩盘是一个错误。”¹¹ 他接着辩称,1987 年的崩盘是一个过大的错误,而 1929 年的崩盘则是一个过小的错误。
An obvious example of the latter is the stock market crash of 1987, a day when the Dow Jones Industrial Average plunged 22.6 percent. The probability of such an event was vanishingly small using conventional theory, and a rational explanation stretches credulity.10 When asked about it, for instance, Eugene Fama said, “I think the crash in ‘87 was a mistake.”11 He went on to argue that the crash of 1987 was an error that was too big and the crash of 1929 was an error too small.
现在如果你去问金融学教授市场有效性,大多数人会搬出套利论据,大意是我们只需要一小批资金充裕的套利者,他们在市场中四处游荡,寻找价格与价值之间出现异常偏差的机会,然后据此买入或卖出¹²。这个论点的美妙之处在于:并非所有人都必须聪明,我们其他人反而能从中受益,因为套利者已经替我们干了活。套利基于负反馈机制,将偏离常态的东西推回到它们本该在的位置。
Now if you ask finance professors about market efficiency, most will fall back on the arbitrage argument, which basically says that we only need a handful of well-capitalized arbitrageurs who will cruise around markets seeking aberrant price-to-value gaps and will buy and sell accordingly.12 The beauty of this argument is not everyone has to be smart and the rest of us benefit from the work of the arbitrageurs. Arbitrage is based on negative feedback, pushing things that are out of line back to where they should be.
关于套利局限性的文献解释了为何套利者并非总能履职。¹³ 这些限制往往是技术性的。例如,以网络公司 3Com 和 Palm 为例——Palm 是 3Com 剥离出来的手持设备业务——
There is a literature on the limits to arbitrage that explains why arbitrageurs can’t always do their jobs.13 Often these limits are technical. For instance, take the case of 3Com, a networking company, and Palm, a hand-
2000 年 3 月初,3Com 公司通过首次公开发行出售了 Palm 公司 5% 的股份,并公开表示将在此后把剩余的 95% 股份分拆给股东。此次发行完成后,每一股 3Com 股票将对应 1.5 股 Palm 股票,外加 3Com 自身业务的相应价值。
held computer company wholly owned by 3Com. In early March 2000, 3Com sold 5 percent of Palm in an initial public offering, with the stated intention of spinning off the other 95 percent to shareholders later in the year. Following the offering, each 3Com share would represent 1.5 shares of Palm as well as the proportionate value of the 3Com operations.
IPO 首日交易中,Palm 股价约为每股 95 美元,对应市值 540 亿美元;3Com 股价约为 82 美元,市值 280 亿美元。这意味着 3Com 的价值约为负 200 亿美元。由于每股 3Com 股份相当于 1.5 股 Palm 股份加上公司自身的运营业务,显而易见的交易策略是做多 3Com、做空 Palm。问题在于,市场上没有足够的 Palm 股票可供借入。因此,尽管套利的数学逻辑清晰无误,套利者却无法执行这一交易。这种市场非效率状态一直持续到足够的 Palm 股票可以借入为止。
On the first day of trading following the offering, Palm shares traded at roughly $95 per share, representing a market capitalization of $54 billion, and 3Com shares were at $82, a $28 billion valuation. This suggested a value for 3Com of roughly negative $20 billion. Given that each 3Com share was worth 1.5 Palm shares plus the company’s own operations, the obvious trade was to go long 3Com and short Palm. The problem was that there was insufficient Palm stock to borrow. So even though the math of the trade was clear, arbitrageurs could not execute the trade. This allowed the inefficiency to persist until sufficient Palm shares became available to borrow.
即便考虑套利行为的各种限制因素,套利者的存在本身仍是一个合理假设。市场上仍有大量资源专门用于套利操作,套利者在确保日常价格有效性方面发挥着不可或缺的作用。
Even after taking into consideration the limits to arbitrage, the existence of arbitrageurs is a reasonable assumption. There remain substantial resources dedicated to arbitrage, and arbitrageurs play an essential role in ensuring efficient prices day to day.
但对于套利论据,还有一个问题值得深究。特雷诺资本管理公司(Treynor Capital Management)总裁杰克·特雷诺(Jack Treynor)在 1987 年发表的一篇关于市场有效性的优秀论文中提出了这一点。
But there are a couple more issues with the arbitrage argument that Jack Treynor, president of Treynor Capital Management, suggests in a fine paper on market efficiency published in 1987.14
第一,套利者自身并非理性,因为他们的投资组合风险上升的速度可能快于收益,这与风险规避原则相悖,因而也不符合预期效用理论。
First, arbitrageurs themselves are not rational because the risk of their portfolios can rise faster than the reward, inconsistent with the principle of risk aversion and hence expected utility theory.
第二,该理论假设了解真实价值的投资者会扩大头寸,而不了解真实价值的投资者会心甘情愿地卖出。正如他所说,“那些做对了的投资者知道自己对了,而那些做错了的投资者也知道自己错了”,并且他们都相应行动。他直截了当地补充道,这“是一种不太可能出现的状况”。
Second, the theory assumes that investors who know true value expand their positions and those who don’t willingly sell. As he says, “Those investors who are right know they are right, while those investors who are wrong know they are wrong” and they all act accordingly. This, he adds flatly, is “an unlikely state of affairs.”
另一个问题是,在整个市场历史的关键时刻,套利者总会缺席。一个被充分记录的案例是长期资本管理公司(LTCM)与“新券”和“旧券”债券。爱丁堡大学社会学教授唐纳德·麦肯齐(Donald MacKenzie)所著的《一部引擎,而非相机:金融模型如何塑造市场》中,有一章精彩地讲述了 LTCM 的故事。
Another problem is that the arbitrageurs have failed to show up at critical junctures throughout the history of markets. One well-documented example is that of Long-Term Capital Management (LTCM) and “on-the-run” and “off-the-run” bonds. There’s a wonderful chapter about LTCM in “An Engine, Not a Camera: How Financial Models Shape Markets” by Donald MacKenzie, a professor of sociology at the University of Edinburgh.15
最新一期发行的债券被称为“新券”。当时,30 年期美国国债是市场的风向标。6 个月前发行的、条件类似的 30 年期债券则被称为“老券”。从数学角度讲,这些债券的价值非常接近,但由于新券流动性更高,因此享有小幅溢价。这笔交易非常直白:如果老券相对于新券价格异常便宜,以两者收益率之间的宽幅利差来衡量,你就买入老券、卖出新券,直到估值差距回归正常。这是套利的基础知识。正因为这是一笔普通型交易,套利者会使用大量债务来放大收益。
The most recent issue of a bond is called on-the-run. At that time, the 30-year Treasury bond was a bellwether security. The comparable 30-year bond issued, say, six months before, is off-the-run. These bonds have very similar values based on math, but since the newer issue is more liquid it commands a small premium. The trade here is very straightforward: If the off-the-run bond gets unusually cheap versus the on-the-run bond, measured by a wide spread between the yields, you buy the off-the-run and sell the on-the-run until the valuation gap reverts to normal. This is arbitrage 101. And because this is a plain vanilla transaction, arbitrageurs use plenty of debt to supercharge their returns.
麦肯齐指出的关键是,当 1998 年这笔交易的价差扩大时,套利者却无影无踪。他写道:¹⁶
The point MacKenzie makes is that as the spread expanded on this trade in 1998, the arbitrageurs were nowhere to be found. He writes:16
随着“利差”扩大,套利机会变得更具吸引力,套利者却并未涌入市场来收窄利差、恢复“常态”。恰恰相反,潜在的套利者继续逃离,利差进一步拉大,加剧了那些留在市场中的机构——比如长期资本管理公司(LTCM)——的困境。
As ‘spreads’ widened, and thus arbitrage opportunities grew more attractive, arbitrageurs did not move into the market, narrowing spreads and restoring ‘normality.’ Instead, potential arbitrageurs continued to flee, widening spreads and intensifying the problems of those who remained, such as LTCM.
交易本身并不是问题,从理论上讲,长期资本管理公司完全可以持有这些证券直到到期,结果也不会差。问题出在杠杆上,它放大了利差微小变动带来的影响。但这里的关键在于,当我们最需要套利者为市场提供负反馈——也就是让价格和价值重新对齐——的时候,他们却没能做到。
The trade itself wasn’t a problem, as in theory LTCM could have held those securities to maturity and done fine. The problem was leverage, which amplified the impact of small changes in the spread. But the essential point here is that at the time when we most need the arbitrageurs to provide the market with negative feedback—that is, to bring price and value back into line—they fail to do so.
通向市场效率的最后一条路径是群体智慧。更正式地说,我们可以将市场称为一个复杂自适应系统。
The final path to market efficiency is the wisdom of crowds.17 To be more formal, we can call the market a complex adaptive system:18
“复杂”意味着有大量异质性主体在相互作用。这些主体可以是大脑中的神经元、蚁群中的蚂蚁,也可以是市场里的投资者;
Complex means there are lots of heterogeneous agents interacting. These can be neurons in your brain, ants in an ant colony, or investors in a market;
适应性的意思是,这些参与者的决策规则会随着环境的变化而做出调整。
Adaptive means that the decision rules of those agents change in response to the environment.
突触连接或增强或减弱,蚂蚁或外出觅食或留在巢中,投资者则根据市场波动买进或卖出。关键在于,决策规则与环境之间存在反馈机制;
Synaptic connections are strengthened or weakened, the ants forage or stay in the nest, or investors buy or sell based on the market’s moves. The essential point is that there is feedback between the decision rules and the environment;
系统意味着整体大于部分之和。还原论行不通——你无法仅通过分析各个组成部分来理解这个系统。
System means that the whole is greater than the sum of the parts. Reductionism doesn’t work. You can’t understand the system solely by analyzing the constituent parts.
以下是关键:集体智慧只有在特定条件下才能发挥作用,这些条件包括多样性、聚合机制和激励机制。以下是相关定义:
Now here’s the key: The wisdom of crowds only works under certain conditions, which include diversity, aggregation, and incentives. Here are some definitions:
多样性意味着,无论是神经元、蚂蚁还是投资者,这些主体都是异质的。在市场中,这意味着有些投资者看重短期或长期视野,有的做基本面或技术分析,甚至还有人根据星象排列进行交易;
Diversity means that the agents, whether neurons, ants, or investors, are heterogeneous. In markets, this means investors who have a short-term or a long-term outlook, do fundamental or technical analysis, or even those who trade based on the alignment of the stars;
聚合意味着存在一种将信息汇集到一起的方式。这对应于你大脑中的突触放电、蚂蚁的信息素轨迹,以及投资者的交易所;
Aggregation means there’s a way to bring information together. That would be synaptic firings in your brain, pheromone trails for ants, and exchanges for investors;
激励意味着做对了有奖赏,做错了受惩罚。激励不一定是金钱上的——对某个物种来说,它可以体现为生存适应性,甚至也可以是声誉。但关键的理念是:好结果得到回报,差表现受到惩罚。
Incentives mean there are rewards for being right and penalties for being wrong. Incentives need not be monetary—they can be represented by fitness for a species or even be reputational. But the important idea is that good results are rewarded and poor performance penalized.
有一个公式可以展示群体智慧在数学上的运作方式。密歇根大学经济学与政治学教授斯科特·佩奇将其称为“多样性预测定理”。
There’s an equation that shows the math of how the wisdom of crowds works. Scott E. Page, a professor of economics and political science at the University of Michigan, calls this the “diversity prediction theorem:”19
集体错误 = 个体平均错误 – 预测多样性
Collective error = Average individual error – Prediction diversity
你可以把“平均个人误差”理解为智慧,“预测多样性”理解为多样性,而“集体误差”则是群体的智慧。
You can think of “average individual error” as smarts, “prediction diversity” as diversity, and the “collective error” as the wisdom of crowds.
从多样性预测定理可以推导出两条公理。第一条是:集体误差总是小于平均个体误差。这意味着,集体的智慧高于集体中每个人的平均猜测水平。对于那些参与市场的人来说,这传达了一个信息——理应保持适当的谦逊。
There are two axioms that follow from the diversity prediction theorem. The first is that the collective error is always less than the average individual error. This means the collective is smarter than the average guess within the collective. For those who participate in markets, this is a message that suggests appropriate humility.
第二,群体的智慧既取决于智慧,也取决于多样性。正如佩奇所强调的,“与众不同与优秀同样重要。” 这凸显了多样性在多种场景中的相关性,包括群体做出的任何决策。
Second, the wisdom of the crowd is equal parts smarts and diversity. As Page stresses, “Being different is as important as being good.” This highlights the relevance of diversity in multiple settings, including any decisions that groups make.
这里有一个简单的例子,可以说明群体智慧是如何运作的。2013 年夏天,我们开了一次会,参会的有 67 名实习生。我们传了一个大罐子,里面装满了软糖豆,请他们各自独立估算罐子里豆子的数量。我们为猜得最准的人准备了奖励,对猜得最离谱的人则威胁要在公开场合让他难堪(不过并没有真的兑现)。这样一来,群体智慧所需的条件就齐备了:多样性、汇总(用电子表格),以及激励机制。
Here’s a simple example to show how the wisdom of crowds works. In the summer of 2013, we had a meeting that included 67 interns. We passed around a large jar of jelly beans and asked them to independently make an estimate of the number of beans in the jar. We offered a reward for the best guess and threatened public shame (without follow through) for the worst one. So the conditions for the wisdom of crowds were in place: diversity, aggregation (a spreadsheet), and incentives.
该组的平均估计值为 1427 颗豆子。罐子里实际装了 1416 颗豆子。因此,集体估计值与实际数字的误差在 1% 以内。这种准确性并非源于精确的个人猜测——个人猜测的平均误差高达 53%。确切地说,是因为猜测足够多样化,最终才得出一个非常好的结果。在这项特定练习中,没有哪位参与者比集体表现更好。
The average estimate of the group was 1,427 beans. The jar contained 1,416 beans. So the collective estimate was within one percent of the actual number. The accuracy was not the result of sharp individual guesses, as the average individual error was 53 percent. Rather, the guesses were sufficiently diverse to get to a very good final result. In this particular exercise, no participant did better than the collective.
虽然这一结果既有趣又有启发性,但它依赖的是一个非常刻意的设定。不过事实证明,集体在更接近市场环境的条件下也能表现良好。其中一个例子是赛马中的同注分彩赌博(pari-mutuel betting)。
While this outcome is interesting and illuminating, it relies on a very contrived setting. But it turns out that collectives can do well in environments closer to markets. One example is pari-mutuel betting in horse racing.
附件 4 展示了一张基于 1.1 万多场赛马比赛的图表。20 横轴是赔率制定者给出的名次预测,纵轴是实际结果。每个点都代表预期结果与实际结果的对比。一条 45 度角的对角线显示了二者的匹配程度。如果你仔细看,会发现赛马下注者并不完美,任何一场比赛的结果都可能偏离很远(稍后我们会看到)。但这些结果已经足够准确,以至于在马场从投注池中扣除标准比例(称为“抽水”)后,想赚钱变得非常困难。
Exhibit 4 shows a plot based on more than 11,000 horse races.20 The horizontal axis is the ordinal finish, as determined by the handicappers, and the vertical axis is the actual outcome. Each dot compares the expected versus the actual result. A line at a 45-degree angle shows how well they match up. If you examine this closely you can see that horse bettors are not perfect, and the results for any particular race can be way off (as we’ll see in a moment). But these results are sufficiently accurate to make it really hard to make money after the track withholds a standard percentage of the betting pool (known as a “takeout”).
附录 4:赛事预测者的准确率为 40
Exhibit 4: Handicappers Are Accurate 40
35
35
30
30
Actual Outcomes (%)
Actual Outcomes (%)
原件此处是表格,PDF 抽取时列结构已丢失,下面只剩按列读出的数字,行列对应关系无法还原。核对数据请打开来源正文。
25 20 15 10 5 0 0 5 10 15 20 25 30 35 40
25 20 15 10 5 0 0 5 10 15 20 25 30 35 40
Predicted Outcomes (%)
Predicted Outcomes (%)
资料来源:Marshall K. Gramm 与 Douglas H. Owens,《同步赛马时代下不同投注池中的彩池投注市场效率》,《南方经济杂志》,第 72 卷,第 4 期,2006 年 4 月,第 926-937 页。
Source: Marshall K. Gramm and Douglas H. Owens, “Efficiency in Parimutuel Betting Markets Across Wagering Pools in the Simulcast Era," Southern Economic Journal, Vol. 72, No.4, April 2006, 926-937.
本·格雷厄姆了解群体智慧。当被问到华尔街专业人士是否比其他人更擅长预测时,他是这么说的:21
Ben Graham knew about the wisdom of crowds. When posed the question about whether Wall Street professionals are better at forecasting than others, here’s what he said:21
嗯,对于这个有趣的问题,我们已经追踪研究了一代人的时间甚至更久。坦率地说,我们的研究结果表明,你其实可以二选一——要么掷硬币,要么听从专家意见的共识,而这两种方式的结果几乎一模一样。你问为什么专家意见的可靠性没那么高,这个问题提得很好,也很有意思。我自己的解释是——
Well, we’ve been following that interesting question for a generation or more. And I must say frankly that our studies indicate that you have your choice between tossing coins and taking the consensus of expert opinion and the results are just about the same in each case. Your question as to why they are not more dependable is a very good one and an interesting one and my own explanation for that is
沃伦·巴菲特:华尔街上的每个人都聪明至极,以至于他们的才智相互抵消。他们知道的一切,基本上都已经反映在了当前的股价水平上,因此未来发生的事代表着他们所不知道的东西。
this: Everybody on Wall Street is so smart that their brilliance offsets each other. And that whatever they know is already reflected in the level of stock prices, pretty much, and consequently what happens in the future represents what they don’t know.
现在我们进入讨论的核心——“激活市场先生”。问题是:市场先生
Now we turn to the heart of the discussion, which is “animating Mr. Market.” The question is: How does Mr.
市场从提供“合理且有理有据”的价格,转变为提供“近乎荒谬”的价格。
Market go from offering prices that are “plausible and justified” to offering prices that are “little short of silly?”
我们相信,答案是“群体智慧”所需的条件中有一项或多项被违背了,于是我们便从“群体智慧”滑向了“群体疯狂”。既然我们是社会性动物,那么最容易遭到破坏的条件便是多样性,这一点毫不奇怪。我们的行为并非各自独立,而是相互关联。而股价本身,又进一步加剧了这种关联过程。
The answer, we believe, is that one or more of the conditions for the wisdom of crowds is violated and hence we go from the wisdom of crowds to the madness of crowds. Given that we are social beings, it is not surprising that the condition most likely to be violated is diversity. Rather than operating in a diverse fashion, we correlate our behaviors. And stock prices themselves contribute to the process of correlation.
社会心理学中有一个经典实验,很好地解释了这一点。这个实验研究社会从众行为,由社会心理学家所罗门·阿什在 1940 年代和 1950 年代构思并执行。在其中一个版本里,阿什让八个人围坐在一张桌子旁。其中七名“参与者”实际上是阿什的同谋,他们事先知情。第八个人才是真正的实验对象。
There’s a classic experiment in social psychology that explains this well. It was about social conformity and was conceived and conducted by the social psychologist Solomon Asch in the 1940s and 1950s. In one version of the experiment, Asch had eight people seated around a table. Seven of those “participants” were Asch’s confederates who were in on the experiment. The eighth was the subject.
阿什给参与者展示了一条参考线(X)和另外三条线(A、B 和 C),其中一条与 X 长度相同。任务很简单,就是判断 A、B、C 中哪条线与 X 一样长。他们总共做了 18 轮。在没有从众压力的情况下,受试者的回答几乎毫无差错。
Asch showed the participants a reference line (X) and three additional lines (A, B, and C), one of which was the same length as X. The simple task was to identify which line—A, B, or C—was as long as X. They did this for 18 rounds. With no pressure to conform, the answers of the subjects were nearly flawless.
实验随后正式开始。阿施示意同伙给出错误答案。在这些测试中,超过三分之一的回答是错误的。此外,四分之三的受试者至少犯过一次错。即便是最初拒绝从众的受试者,通常也会在某一轮或更多轮中最终选择随大流。22 同样值得注意的是,大约四分之一的受试者始终保持独立判断。23
The experiment then started for real. Asch signaled his confederates to give the wrong answer. In these trials, more than one-third of the responses were wrong. Further, three out of the four subjects answered wrong at least once. Even subjects who initially resisted going with the group commonly ended up doing so for a round or more.22 It is also worth noting that about one-quarter of the subjects did remain independent.23
在描述这些实验时,阿希思考那些从众者当时的内心活动。²⁴ 他提出了三种可能的扭曲情形。第一种是判断扭曲,即受试者知道正确答案,但当其他人给出不同答案时感到矛盾,于是认为群体更明智,从而否定了自己的答案。第二种是行动扭曲,指受试者知道正确答案,但觉得随大流——即便犯错——比特立独行——即便正确——更舒服。正如著名经济学家约翰·梅纳德·凯恩斯在《通论》第 12 章中所写:“世俗智慧告诉我们,因循守旧而失败,比特立独行而成功,更能保全名声。”²⁵
In writing about the experiments, Asch wondered what was going through the minds of those who conformed.24 He suggested three possible distortions. The first is judgment, where the subject knows the answer, feels conflict when others answer differently, and assumes the group knows better and so rejects his own answer. Second is action, which suggests that the subject knows the answer but feels more comfortable going with the group and being wrong than standing out and being right. As the renowned economist John Maynard Keynes wrote in chapter 12 of The General Theory, “Worldly wisdom teaches that it is better for the reputation to fail conventionally than to succeed unconventionally.”25
最后一个扭曲因素是感知,即群体的意见实际上会改变个体对正在发生的事情的感知。阿希于 1996 年去世,因此他从未有机会看到哪一种解释最有可能。
The final distortion is perception, which suggests the group opinion actually alters how the subject perceives what is going on. Asch died in 1996, so he never had the chance to see which explanation is most likely.
时间快进到阿施实验 50 年后的埃默里大学校园里,在一个功能性磁共振成像(fMRI)实验室中。神经科学教授格雷格·伯恩斯决定在受试者身处 fMRI 扫描仪内时,复刻阿施的实验。这让伯恩斯和他的同事得以在受试者做决定时,窥视他们的大脑活动。
Fast forward 50 years from the time Asch did his experiments to a functional magnetic resonance imaging (fMRI) lab on the campus of Emory University. Greg Berns, a professor of neuroscience, decided to replicate the Asch experiments while subjects were in the fMRI machine. This allowed Berns and his colleagues to peer into the brains of the subjects as they decided.26
伯恩斯选择了和阿希不同的任务。他展示了一对经过旋转的三维物体。在大约一半的情况下,物体是相同的,另一半情况下,物体是镜像的,因此不同。在控制条件下,受试者在 14% 的情况下选错答案,这表明这项任务比匹配线条稍难一些。当研究人员引入他人的答案时,错误率上升到了 41%,但仍有大约四分之一的受试者保持独立判断。尽管任务不同,但科学家们成功复现了阿希的基本发现。
Berns selected a different task than that of Asch. He showed a pair of three-dimensional objects that were rotated. In roughly half the instances the object was the same and in the other half the object was a mirror image, hence different. Under control conditions, the subject selected the incorrect answer 14 percent of the time, indicating that the task was somewhat more difficult than matching lines. When the researchers introduced the answers of others, the error rate rose to 41 percent, but about a quarter of the subjects remained independent. Even though the task was different, the scientists successfully replicated Asch’s basic findings.
事情的转折就在这里。伯恩斯不仅能观察到实验的结果,还能看到受试者在做决定时大脑的哪些区域在活跃。如果是判断与行动层面的认知偏差,你预期前脑会有活动;而如果是感知层面的扭曲,活跃区域应该在后脑——那里正是视觉与知觉区域所在的位置。
Here’s where things got interesting. Berns could not only see the results of the trials but could also observe what parts of the brain were active as the subjects decided. For distortions of judgment and action you would expect activity in the forebrain, whereas a distortion of perception would be in the posterior brain where your visual and perceptual regions reside.
是那些从众的受试者后脑活跃。这表明群体的意见影响了受试者对情境的感知。同样令人惊讶的是,研究人员并未发现前额叶脑区的活动有显著变化,该区域通常与更高层次的加工处理有关,比如对行动的扭曲。
It was the posterior brain that was active for those subjects who conformed. This suggests the group’s opinion affected how the subject perceived the situation. As surprising, the researchers did not find a substantial change in activity in the frontal lobe, associated with higher level processing such as a distortion of action.
如今,我们都有过这样的经历——或者可以理解这种情境——即我们任由他人的决定影响了自己。换句话说,我们明知正确答案是什么,却做出了不同的选择。然而,在实验后的一项调查中,只有 3% 的受试者承认自己知道正确答案,却仍随了大流。
Now we have all either been in, or can relate to, situations where we allowed the decisions of others to influence us. In other words, we knew the right answer but chose differently. But in a survey following the experiments, only three percent of the subjects admitted to knowing the right answer and going with the majority anyway.
伯恩斯这样总结这场实验:“我们总以为眼见为实”,但实际上,你看到的是群体让你相信的东西。²⁷
Berns summed up the experiment, “We like to think that seeing is believing,” but seeing is believing what the group tells you to believe.27
这个实验还有一点值得一提——那些保持独立思考的人的大脑内部发生了什么。这些受试者的杏仁核活动增强,而杏仁核是你大脑中发出立即行动信号的部分。恐惧是杏仁核的强大触发器,它正是“战斗或逃跑”反应背后的驱动因素。所以,尽管那些保持独立的人值得我们钦佩,但重要的是要知道,他们这样做时必须克服一种不愉快的感觉。
There’s another element of the experiment worth mentioning, and that is what happened inside the brains of those who remained independent. Those subjects experienced increased activity in the amygdala, the part of your brain that cues for immediate action. Fear is a powerful trigger for the amygdala, and it’s behind the fight-or-flight response. So while those who stayed independent deserve our admiration, it is important to know that they had to overcome an unpleasant sense to do so.
在第八章中,格雷厄姆反复强调独立思考的重要性。不要陷入认为股市的波动是在向你传递某种信息的误区。你可以把市场先生的价格当作信息来源,但不要被它牵着鼻子走。阿什和伯恩斯的实验告诉我们,做到这一点并不容易。
Throughout chapter 8, Graham stresses the importance of thinking for yourself. Don’t get caught up in the notion that the stock market’s gyrations are telling you something. Use Mr. Market’s prices for information but don’t be influenced by them. The experiments by Asch and Berns tell us that this is hard to do.
多样性的缺失至关重要,它能把市场先生从健康状态推向狂躁或抑郁。而这里的关键在于:导致市场无效的那个因素——相关性信念——恰恰使得利用这种无效变得困难。融入群体的欲望非常强烈,而脱离主流对大多数人来说是可怕的。
Diversity breakdowns are crucial to pushing Mr. Market from healthy to manic or depressed. And herein is the critical point: The very factor that causes market inefficiency—correlated beliefs—makes exploiting that inefficiency difficult. The desire to be part of the crowd is powerful, and being apart from the crowd is scary for most.
但还有一个值得强调的关键因素,那就是多样性的丧失与资产价格的变动之间存在非线性关系。换句话说,你可以在一段时间内失去多样性而相安无事。但随后就会发生突然的转变,你可能遭遇重大且出人意料的剧变。
But there’s another essential element worth stressing, which is that the loss in diversity and the movement in asset prices have a non-linear relationship. In other words, you can lose diversity for a while and nothing happens. But then there’s a sudden shift and you can get big, unexpected changes.
我们先看一个具体的例子:伦敦的千禧桥。千禧桥是一个多世纪以来在泰晤士河上修建的第一座人行桥,将北岸的圣保罗大教堂与南岸的泰特现代美术馆和环球剧场连接起来。这座桥由著名建筑师诺曼·福斯特设计,由声誉卓著的工程公司奥雅纳承建。
Let’s start with a physical example, the Millennium Bridge in London. The Millennium Bridge was the first footbridge built over the River Thames in over a century, and connects St Paul’s Cathedral on the north with the Tate Modern and the Globe Theatre on the south. The bridge was designed by the famous architect, Norman Foster, and built by the reputable engineering firm, Arup.
这座桥于 2000 年 6 月 10 日午餐时间正式开通。没过多久,它就开始左右摇晃。这在桥梁行业是个大问题。如果你去看当天人们在桥上行走的视频,画面就像一群企鹅在慢慢挪动。28 桥立即被关闭,所有相关方都倍感尴尬。
The bridge officially opened at lunchtime on June 10, 2000. Within a few moments, it started swaying from side to side. This is a major problem in the bridge business. If you watch the video of the people crossing the bridge on that day, it looks like a bunch of penguins inching along.28 The bridge closed immediately, to the embarrassment of all involved.
发生了什么?当然,桥梁工程师清楚垂直作用力,并在设计时已将其纳入考量。但你行走时也会产生一些侧向力。通常情况下,桥梁足够坚固,可以应对这种侧向力,而且当人们行走时,这些力量往往会相互抵消。
What happened? Naturally, bridge makers know about vertical force and accommodate it in their design. But when you walk you also generate a bit of lateral force. In general, bridges are stiff enough to deal with that and when people walk, the forces tend to cancel out.
但千禧桥的横向阻尼装置不够。所以桥一开始晃动,行人就本能地加大步幅以保持平衡。这一来他们的步伐渐渐同步,结果反而放大了晃动的效果。
But the Millennium Bridge had insufficient lateral dampeners. So once the bridge started to sway, the pedestrians widened their gait to maintain stability. This led them to synchronize their steps, which further amplified the effect.
这段故事对我们的关键要点在于,摇摆现象只在行人数量超过某个临界阈值后才出现。如展图 5 所示,当行人少于 165 名时几乎没有摆动。但只要超过 165 人,作用便启动了。微小的增量变化引发了大范围效应。
The essential part of the story for our purpose is that the swaying only happened beyond a certain threshold of pedestrians. As exhibit 5 shows, there is little swaying up to 165 pedestrians. But above 165, and the action kicks in. A small incremental change leads to a large-scale effect.29
展品 5:千禧桥在超过 165 人时出现晃动 200
Exhibit 5: The Millennium Bridge Wobbled with More Than 165 People 200
Crowd 100 Size
Crowd 100 Size
| 165 人 | 0 | 7 |
| 晃动幅度 | 0 | 时间 |
165 People 0 7 Wobble Amplitude 0 Time
来源:基于 Steven H. Strogatz、Daniel M. Abrams、Allan McRobie、Bruno Eckhardt 和 Edward Ott 的论文《理论力学:千禧桥上的行人同步现象》,发表于《自然》杂志,第 438 卷,2005 年 11 月 3 日。
Source: Based on Steven H. Strogatz, Daniel M. Abrams, Allan McRobie, Bruno Eckhardt, and Edward Ott, “Theoretical Mechanics: Crowd Synchrony on the Millennium Bridge,” Nature, Vol. 438, November 3, 2005.
注:摇摆幅度以厘米为单位。
Note: Wobble amplitude in centimeters.
我们相信,同样的道理在市场中也是成立的。¹在现实中很难实时衡量多样性,但在基于代理的模型中,我们可以清晰地看到这种非线性特征。布兰迪斯大学的经济学家布莱克·勒巴伦就开发了这样一个模型。¹勒巴伦的世界里有 1000 个代理,他们交易一只股票,懂得投资组合理论,并使用各种交易规则。股票的价值由未来的股息决定,而勒巴伦将相关数字建立在历史结果之上。勒巴伦能够复现我们在真实市场中看到的许多特征,包括聚集波动性和肥尾现象。图表 6 展示了结果。
We believe the same thing is true in markets.30 It’s hard to have a clear measure of diversity in real time, but we see these nonlinearities clearly in agent-based models. Blake LeBaron, an economist at Brandeis University, developed such a model.31 LeBaron’s world has 1,000 agents who trade a stock, know portfolio theory, and use various trading rules. The value of the stock is determined by future dividends, and LeBaron based the numbers on historical results. LeBaron is able to replicate many of the features we see in real markets, including clustered volatility and fat tails. Exhibit 6 shows the results.
附录 6:基于智能体的模型显示多样性对价格的影响呈非线性关系
Exhibit 6: Agent-Based Model Shows Non-Linear Relationship between Diversity and Price
来源:Blake LeBaron,“协同演化环境中的金融市场有效性”,《社会主体仿真研讨会论文集:架构与制度》,阿贡国家实验室与芝加哥大学,2000 年 10 月,阿贡 2001,第 33-51 页。
Source: Blake LeBaron, “Financial Market Efficiency in a Coevolutionary Environment,” Proceedings of the Workshop on Simulation of Social Agents: Architectures and Institutions, Argonne National Laboratory and University of Chicago, October 2000, Argonne 2001, 33-51.
为便于讨论,你可以重点看图表左侧的前 80 个周期。上方是股价,呈稳步上升趋势;下方是多样性指标。你可以观察到,多样性在下降,而股价却在上涨。这是一笔拥挤的交易——所有人都在做同样的事,并且因此赚到了钱。
For the purpose of our discussion, you can focus on the first 80 periods on the left of the exhibit. On the top you see the stock price, which is in steady ascent. On the bottom you see a measure of diversity. What you can observe is that diversity is dropping even as the stock price rises. This is a crowded trade. Everyone is doing the same thing and making money doing it.
随后股价急剧下跌,因为再也没有买家继续推高股价。与此同时,种群内部的多样性开始增加,市场健康度也有所恢复。
The stock price then drops precipitously as there are no more buyers to bid the stock higher. At the same time, diversity increases in the population and restores some health.
在我们进入本次讨论的最后一部分之前,先回顾一下要点:
Before we move to the final part of this discussion, let’s review the main points:
“多样性”这一概念对于激活市场先生至关重要。当市场存在多样性时,往往能形成有效市场,市场先生对价值的判断也就相对合理。一旦多样性丧失,群体的智慧就会翻转成群体的疯狂。市场先生会变得狂躁或抑郁,价格便会偏离价值。
1. The concept of diversity is essential to animating Mr. Market. When we have diversity we tend to have efficient markets, and Mr. Market’s idea of value is plausible. When we lose diversity, the wisdom of crowds flips to the madness of crowds. Mr. Market becomes manic or depressed and prices depart from value.
2. 多样性的丧失与资产价格之间并非线性关系。随着多样性下降,市场的脆弱性会增加,但一切看起来都还不错。事实上,看起来比不错还要好,因为市场参与者通常都在赚钱,有时甚至被鼓励使用债务来提高回报。
2. The loss of diversity is not linearly related to asset prices. As diversity declines, the fragility of the market increases but everything seems fine. In fact, it seems better than fine because market participants are generally making money and sometimes even encouraged to use debt to enhance their returns.
3. 当几乎所有人都倾向于某种观点——无论是看涨还是看跌——从众的心理拉力会非常强大。这就是阿施实验的主要教训。而当这种心理拉力由股票价格引导时,市场先生就不再是为你提供信息,而是在影响你。你已落入他的掌控之下。
3. When nearly everyone adopts a point of view, whether it’s bullish or bearish, the psychological pull to conform is powerful. This is the main lesson from the Asch experiment. And when that psychological pull is led by stock prices, Mr. Market is no longer informing you, he is influencing you. You have come under his sway.
这些观点引出了第 8 章中可能最重要的一段话。格雷厄姆写道:
These points lead to what may be the most important paragraph in chapter 8. Graham writes:
真正的投资者极少会被迫卖出股票,在其他任何时候他都可以自由地忽略当前的股价报价。他只需在符合自己账目情况时才去关注它并据此行动,仅此而已。因此,那些允许自己因不合理的市场下跌而惊慌失措或过度担忧的投资者,反而是变相地将自己的基本优势转化成了基本劣势。
The true investor scarcely ever is forced to sell his shares, and at all other times he is free to disregard the current price quotation. He need pay attention to it and act upon it only to the extent that it suits his book, and no more. Thus the investor who permits himself to be stampeded or unduly worried by unjustified market declines is perversely transforming his basic advantage into a basic disadvantage.
如果根本没有市场报价,这个人反而会过得更好,因为他就能免去由他人判断失误所带来的精神折磨。
That man would be better off if there were no market quotation at all, for he would be spared the mental anguish caused him by other persons’ mistakes of judgment.
所罗门·阿什遇见股票市场。
Solomon Asch meets the stock market.
逆向思维 + 一台计算器
Contrarian Streak + a Calculator
现在让我们转向讨论的最后部分——如何利用市场先生为你自身谋利。而我们认为,没有谁能比 Baupost 集团创始人塞思·卡拉曼在 2008 年分享的那句话更精辟:“价值投资的核心,就是将逆势倾向与计算器结合在一起。”
Now let us turn to the final part of the discussion, which is how to use Mr. Market to your benefit. And we don’t think you can do better than a line that Seth Klarman, founder of The Baupost Group, shared in 2008: “Value investing is at its core the marriage of a contrarian streak and a calculator.”32
这条信息在我们看来包含两个部分。第一是要做一个逆向投资者。这与我们一直在讨论的所有内容完全一致。正如沃伦·巴菲特所说,“别人贪婪时我恐惧,别人恐惧时我贪婪。”
There are two parts to this message, as we interpret it. The first is to be a contrarian. This is fully consistent with everything we have been discussing. As Warren Buffett has said, “Be fearful when others are greedy, and be greedy when others are fearful.”33
不过,为了特立独行而特立独行是个坏主意,因为共识有时候是对的。电影院着火时,你当然应该赶紧从门口往外跑。正反馈会改变状态,而有时候,为了进步或安全,状态确实需要被改变。
However, being a contrarian for the sake of being a contrarian is a bad idea because the consensus is right sometimes. When the movie house catches on fire, you should by all means run out the door. Positive feedback changes the state, and sometimes the state needs to be changed for advancement or safety.
因此,信息的第二部分同样至关重要。计算器能帮你判断价格所反映的预期,是否与基本面——也就是对公司未来财务成果的合理预判——脱节了。
So the second part of the message is equally crucial. The calculator allows you to assess whether the expectations, as reflected in the price, are out of sync with the fundamentals, a reasonable sense of a company’s future financial results.
克拉曼在马里兰州巴尔的摩的皮姆利科赛马场附近长大,小时候在那里消磨了不少时光。
Klarman grew up near the Pimlico horse race track in Baltimore, Maryland, and spent a lot of time there as a
孩子。赛马是一个有用的比喻,可以用来说明预期与基本面之间的道理。
kid. Horse racing is a useful metaphor to make the point about expectations and fundamentals.
在美国,赢得三冠王(Triple Crown)能让一匹马跻身赛马界的万神殿。这之所以困难,是因为它要在短短五周内,完成三场不同距离的比赛(肯塔基德比 Kentucky Derby、普利克内斯锦标赛 Preakness Stakes、贝尔蒙特锦标赛 Belmont Stakes),距离分别为 1.25 英里、1.1875 英里和 1.5 英里。2014 年夏天,一匹名叫“加州铬”(California Chrome)的漂亮小公马横空出世。在参加肯塔基德比之前,他生涯 10 场比赛赢了 6 场,并且在前三站中已连胜 4 场。
In the U.S., winning the Triple Crown puts a horse in the pantheon of racing. It’s difficult to do because it entails three races (Kentucky Derby, Preakness Stakes, Belmont Stakes), over three different distances (1.25, 1.1875, and 1.5 miles) all in just five weeks. In the summer of 2014, a beautiful colt named California Chrome came along. He had won 6 of the 10 races he had run prior to the Kentucky Derby and had won 4 in a row leading up to the first leg.
加州铬(California Chrome)以 1 又 3/4 个马身的优势赢得了肯塔基德比,随后又以 1 又 1/2 个马身的优势夺得普里克内斯大奖。
California Chrome won the Kentucky Derby by 1 ¾ lengths and went on to win the Preakness by 1 ½ lengths.
这一胜让他距离赛马界的永恒传奇仅差一场胜利。
This put him just one win away from horse racing immortality.
在这个例子里,市场先生就是那群同注分彩的赌客。三冠王候选赛马就像光鲜性感的高速成长股,人人都想押注它们。这匹马的马主自然也对其前景极其乐观,并不忌讳公开自己的看法。赛事预测师们同样看好,“加州铬”出赛时的赔率是 3 赔 5。这个赔率意味着它有 62.5% 的胜率。
In this case, Mr. Market is the collection of pari-mutuel bettors. Triple Crown contenders are like shiny, sexy growth stocks. Everyone wants to bet on them. Naturally, the horse’s handlers were also very bullish on his prospects and were not afraid to share their views with the public. The handicappers were bullish as well, as California Chrome went off at 3-to-5 odds. Those odds suggest a 62.5 percent chance of winning the race.
作为一个不受价格影响的价值投资者,你会想弄清楚这个概率是否公平地反映了这匹马的前景。换句话说,基本面能否达到预期?
As a value investor unaffected by the price, you would want to understand whether that probability was a fair representation of the horse’s prospects. In other words, would the fundamentals live up to the expectations?
有两种方式来看待这个问题。
There are a couple of ways to look at this.
首先是基础成功率。自 1875 年以来,共有 30 匹马有机会赢得三冠王,但只有 11 匹成功,成功率 37%。不过 1950 年前后差异显著:1950 年之前,尝试的 9 匹马中有 8 匹获胜,成功率接近 90%;而 1950 年之后,21 匹中仅 3 匹成功,成功率不到 15%,自 1978 年 Affirmed 之后更是无一成功。因此,基于过去 65 年的战绩,62.5% 的概率听起来未免有些过于乐观。
First is the base rate of success. Since 1875 there have been 30 horses in a position to win the Triple Crown, but only 11 achieved the feat. That’s a 37 percent success rate. But there was a marked difference before and after 1950: Before 1950, 8 of the 9 horses that tried were victorious, close to a 90 percent rate. But after 1950 only 3 of 21 won, less than a 15 percent success rate, and none have succeeded since Affirmed did so in 1978. So the 62.5 percent probability sounds a bit rich based on the last 65 years of results.
一个合理的想法是,“加州铬”的速度证明了它的赔率合理。有一种方法可以衡量这一点。它叫做 贝耶速度指数(Beyer Speed Figure),衡量的是马匹在赛道条件调整后的表现。具体细节不重要;你真正需要知道的是,速度指数越高,马匹跑得越快。图 7 列出了包括“加州铬”在内的最近八匹“三冠王”候选马,你可以看到它是其中速度最慢的一匹。34
A reasonable thought is that California Chrome’s speed justified his odds. There is a way we can measure that. It’s called a Beyer Speed Figure and measures a horse’s performance adjusted for track conditions. The details are not important; all you really need to know is higher speed figures equal faster horses. Exhibit 7 shows the last eight Triple Crown aspirants, including California Chrome, and you can see that he’s the slowest of the lot.34
附表 7:最后八位三冠王挑战者“银魅”的拜尔速度指数
Exhibit 7: Beyer Speed Figures for the Last Eight Triple Crown Aspirants Silver Charm
Smarty Jones
Smarty Jones
War Emblem
War Emblem
Funny Cide
Funny Cide
Real Quiet
Real Quiet
Charismatic
Charismatic
Big Brown
Big Brown
California Chrome
California Chrome
190 200 210 220 230 240 来源:史蒂文·克里斯特;www.drf.com。
190 200 210 220 230 240 Source: Steven Crist; www.drf.com.
于是我们有了两项基本指标:一个是成功率低的基础概率,另一匹是一匹试图创下壮举但速度并不特别快的赛马。在这种情况下,市场先生过于乐观了,你应该卖出。果然,加州铬金在贝尔蒙特锦标赛中只获得第四名,让前来见证历史的上十万名粉丝大失所望。
So we now have two fundamental indicators. We have a base rate of low success and a horse that is not particularly fast trying to achieve the feat. In this case, Mr. Market is much too optimistic and you should sell. Indeed, California Chrome finished in 4th place in the Belmont Stakes, disappointing more than 100,000 fans who came to see history made.
事实证明,三冠王候选赛马的赔率过高是常有的事。图表 8 列出了同样的八匹马,附带它们各自的隐含胜率以及实际完赛名次。这些马几乎全都是热门马,但它们的赔率却一贯过于乐观。
It turns out that overinflated odds are common with Triple Crown contenders. Exhibit 8 shows the same eight horses along with their implied probability of winning and their actual finish. Almost all of these horses were among the favorites, but their odds were consistently too optimistic.
表 8:最近八匹三冠王候选马的概率与结果 概率 完赛
Exhibit 8: Probability and Results for Last Eight Triple Crown Aspirants Probability Finish
| 小银驹 | 50% | 第 2 名 | |
| 真静 | 56 | 第 2 名 | |
| 魅惑之力 | 38 | 第 3 名 | |
| 战争徽记 | 45 | // | 第 8 名 |
| 搞笑西迪 | 50 | 第 3 名 | |
| 聪明琼斯 | 71 | 第 2 名 | |
| 大布朗 | 77 | * | 最后一名 |
| 加州铬 | 63 | 第 4 名 |
Silver Charm 50% 2nd Real Quiet 56 2nd Charismatic 38 3rd War Emblem 45 // 8th Funny Cide 50 3rd Smarty Jones 71 2nd Big Brown 77 * Last California Chrome 63 4th
资料来源:《纽约时报》2014 年 6 月 6 日,巴里·贝拉克撰写的《与三冠王擦肩而过的 12 位竞争者》;belmontstakes.org;瑞信。注:// = 未按比例(落后冠军 19.5 个马身);* = 被放松缰绳。
Source: Barry Bearak, “12 Contenders Who Just Missed Out on a Triple Crown,” New York Times, June 6, 2014; belmontstakes.org; Credit Suisse. Note: // = Not to scale (finished 19 ½ lengths behind winner); * = Eased.
在这种情况下,逆向思维会说“研究押注热门以外的选项”,而计算器会告诉你,赔率高估了获胜的概率。
In this case, the contrarian streak would say “examine betting against the favorite” and the calculator would tell you that the odds overstate the probability of winning.
赛马比投资简单得多,因为预期是明摆着的,比赛一结束冠军就揭晓。而在股市里,你必须从股价反推出市场预期,而且市场本质上永不停歇。但心态还是一样的。
Horse racing is much simpler than investing because the expectations are explicit and the race reveals the winner. In the stock market, you have to reverse-engineer expectations from stock prices and the market is essentially perpetual. But the mindset remains the same.
换一个比喻来说:预期就是跳高运动员面前的横杆高度,而基本面则是这家公司实际能跳多高。价值投资者寻找的是预期错位。由于市场先生设定横杆的高度飘忽不定,机会往往来了又走。
To use another metaphor, expectations are where the bar is set for the high jumper, and fundamentals are how high the company can jump. Value investors seek expectations mismatches. Because Mr. Market is erratic in where he sets the bar, opportunities tend to come and go.
或许投资者能问出的最重要的问题是:“什么已经被价格反映了?”由此出发,问题就变成了这家公司的财务业绩是会达到、超越还是低于价格所体现的预期。
Perhaps the single most important question an investor can ask is: “What’s priced in?” From there, the issue becomes whether a company’s financial results will meet, exceed, or come up shy of what’s in the price.
虽然实际操作中各有不同,但几乎所有价值投资者都认同一个理念:一项金融资产的价值,就是其未来自由现金流量的现值。哥伦比亚商学院金融学教授布鲁斯·格林沃尔德(Bruce Greenwald)提出了一套既实用又有效的价值思考方法。你还可以将这套方法追溯到估值领域的一些开创性工作。
While there may be differences in practice, almost all value investors accept the idea that the value of a financial asset is the present value of future free cash flow. Bruce Greenwald, a professor of finance at Columbia Business School, has laid out a way to think about value that is useful and practical. You can also tie it back to some of the seminal work in valuation.
基本思路是这样的。你的估值过程从谨慎计算资产价值开始。这是资产的真实价值,扣除相应的负债后得出的。你可以把这视为价值的基础。大多数股票的交易价格都高于这个价值。
Here’s the basic idea. You start your valuation process with a careful calculation of asset value. This is what the assets are actually worth, net of the appropriate liabilities. You can think of this as the bedrock of value. Most stocks trade at a price above this value.
接下来是盈利能力,它反映了按资本成本资本化的公司正常化收益。这一价值假定当前收益水平(经非经常性项目调整后)是可持续的。
Next is earnings power, which reflects the normalized earnings of the company capitalized by the cost of capital. This value assumes the level of current earnings, adjusted for unusual items, is sustainable.
最后一个部分——也是最需要保持怀疑态度的部分——是增长的价值,或者更准确地说,是未来创造的价值。35 图表 9 展示了价值的这三个组成部分。
The final piece, and the one that demands the most skepticism, is the value of growth, or more accurately, future value creation.35 Exhibit 9 shows these three components of value.
表 9:价值的组成部分 = 总价值
Exhibit 9: The Components of Value = Total Value
增长的价值
- Value of Growth
盈利能力的价值(Earnings Power Value)
- Earnings Power Value
资产价值来源:布鲁斯·C.N. 格林沃尔德、贾德·卡恩、保罗·D. 桑金、迈克尔·范·比马,《价值投资:从格雷厄姆到巴菲特及其超越》(纽约:约翰·威利父子出版公司,2001 年),第 35–43 页。
Asset Value Source: Bruce C.N. Greenwald, Judd Kahn, Paul D. Sonkin, and Michael van Biema, Value Investing: From Graham to Buffett and Beyond (New York: John Wiley & Sons, 2001), 35-43.
如果你读过估值领域的奠基性论文之一——默顿·米勒和弗兰科·莫迪利亚尼在 1961 年发表的那篇,你会看到他们认为一家公司的价值等于稳态价值加上增长机会的现值。米勒和莫迪利亚尼指出,这种方法“具有若干具有启发性特征,值得在估值讨论中得到更广泛的应用”。这与格林沃尔德多年来倡导的模型高度吻合。³⁶
If you read one of the foundational papers on valuation, that of Merton Miller and Franco Modigliani from 1961, you will see that they suggest the value of a firm is a steady-state value plus the present value of growth opportunities. Miller and Modigliani suggest that this approach “has a number of revealing features and deserves to be more widely used in discussions of valuation.” This matches quite closely with the model that Greenwald has advocated for over the years.36
Conclusion
Conclusion
以下是本次讨论的总结。首先,阅读《聪明的投资者》第 8 章和第 20 章,以及凯恩斯《通论》的第 12 章,有助于塑造投资者对待市场应有的正确态度。
Here’s a summary of this discussion. First, reading chapters 8 and 20 from The Intelligent Investor, as well as chapter 12 from Keynes’s General Theory, can help shape the proper attitude an investor should have toward markets.
其他要点如下:
The other main points are as follows:
要做主动投资,你必须同时相信尤金·法玛和罗伯特·席勒都是对的,只是不能在同一时间。你需要市场低效来创造机会,又需要市场高效让这些机会转化为回报。
To be an active investor, you must believe both Eugene Fama and Robert Shiller are correct, just not at the same time. You need inefficiency to get opportunities and efficiency for those opportunities to turn into returns.
市场先生依然是思考市场的一个极为有力的比喻。将市场拟人化,能让这一概念不那么抽象,更加具体。
Mr. Market remains a very powerful metaphor for thinking about markets. Anthropomorphizing the market makes the story less abstract and more concrete.
要让市场先生活起来,一种方式是把市场理解为复杂的自适应系统,或者运用群体智慧。关键在于,群体在某些条件下是明智的,而一旦这些条件遭到破坏,群体就会变得疯狂。
One way to animate Mr. Market is to understand the market as a complex adaptive system, or to apply the wisdom of crowds. What’s key is that crowds are wise under some conditions and mad when any of those conditions are violated.
多元化崩溃,既可能源于社会原因,也可能出于技术原因,会导致极端情况出现,进而带来机会。
Diversity breakdowns, which can happen for sociological as well as technical reasons, lead to extremes and hence opportunity.
记住塞思·卡拉曼的那句话:你在寻找的是那些一致的信念导致预期被错误定价,从而找到赚钱之道的情况。三冠王竞争者就生动地展示了这一点。
Remember the line from Seth Klarman: You are looking for cases where uniform belief has led to a mispricing of expectations and thus a way to make money. The Triple Crown contenders show this vividly.
以上内容基于 2015 年 1 月 30 日在哥伦比亚学生投资管理协会会议上的演讲整理而成。
The preceding is based on a presentation at the Columbia Student Investment Management Association Conference delivered on January 30, 2015.
尾注
1 引自本·格雷厄姆的学生马歇尔·温伯格在视频《本·格雷厄姆的遗产》(由海尔布伦格雷厄姆与多德投资中心制作)中的访谈。见 https://www.youtube.com/watch?v=m1WLoNEqkV4。格雷厄姆引用的是斯宾诺莎 1677 年出版的《伦理学》。这句话的拉丁文原文是“sub specie aeternitatis”,通常理解为“普遍且永恒为真的事物”。
Endnotes 1 Quoted from an interview with one of Ben Graham’s students, Marshall Weinberg, in the video “The Legacy of Ben Graham,” produced by the Heilbrunn Center for Graham and Dodd Investing. See https://www.youtube.com/watch?v=m1WLoNEqkV4. Graham was quoting Spinoza’s Ethics, published in 1677. The phrase, in Latin, is “sub specie aeternitatis” and is generally taken to mean “what is universally and eternally true.”
2 参见 http://www.businesswire.com/news/home/20111115006090/en/Warren-Buffett-Remarks-European-Debt-Crisis-%E2%80%9CBuffett#.VM-dOCyJLd4。巴菲特说:“如果你理解了《聪明的投资者》(本杰明·格雷厄姆,1949 年)第 8 章和第 20 章,以及《通论》(约翰·梅纳德·凯恩斯,1936 年)第 12 章,你就不需要再读任何其他东西,可以关掉电视了。”
2 See http://www.businesswire.com/news/home/20111115006090/en/Warren-Buffett-Remarks-European-Debt-Crisis-%E2%80%9CBuffett#.VM-dOCyJLd4. Buffett said, “If you understand chapters 8 and 20 of The Intelligent Investor (Benjamin Graham, 1949) and chapter 12 of the General Theory (John Maynard Keynes, 1936), you don’t need to read anything else and you can turn off your TV.”
区分投资者与投机者是一件棘手的事。在《证券分析》一书中,格雷厄姆和多德提出:“投资操作是经过深入分析后,承诺本金安全且回报令人满意的操作。不符合这些要求的操作即为投机。”见本杰明·格雷厄姆与戴维·L·多德合著《证券分析》(纽约:麦格劳-希尔出版社,1934 年)。但正如《华尔街日报》记者贾森·茨威格所证明的那样,这个定义存在不足。见 http://blogs.wsj.com/totalreturn/2013/02/28/are-you-an-investor-or-a-speculator-part-one/ 和 http://blogs.wsj.com/totalreturn/2013/02/28/are-you-an-investor-or-a-speculator-part-two/。
3 Distinguishing between investors and speculators is tricky. In Security Analysis, Graham and Dodd suggested that, “An investment operation is one which, upon thorough analysis, promises safety of principal and a satisfactory return. Operations not meeting these requirements are speculative.” See Benjamin Graham and David L. Dodd, Security Analysis (New York: McGraw-Hill, 1934). But as Jason Zweig, a journalist at the Wall Street Journal demonstrates, this definition is lacking. See http://blogs.wsj.com/totalreturn/2013/02/28/are-you-an-investor-or-a-speculator-part-one/ and http://blogs.wsj.com/totalreturn/2013/02/28/are-you-an-investor-or-a-speculator-part-two/.
4 参见 http://edge.org/conversation/how-to-win-at-forecasting。
4 See http://edge.org/conversation/how-to-win-at-forecasting.
5 沃伦·E·巴菲特,《致股东信》,伯克希尔·哈撒韦年报,1987 年。详见 www.berkshirehathaway.com/letters/1987.html。
5 Warren E. Buffett, “Letter to Shareholders,” Berkshire Hathaway Annual Report, 1987. See www.berkshirehathaway.com/letters/1987.html.
6 在与一些投资者的交流中,《华尔街日报》记者贾森·茨威格曾就这句名言写下这样一段话:“我给沃伦·巴菲特打了电话问他。他比任何在世的人都更了解格雷厄姆的著作,可当我把他带到你引用的那两段文字面前时,他感到很意外。他原本跟我一样,以为格雷厄姆写过这句话。经过几分钟的出声思考后,他意识到自己可能从未真正读到过这句格言,而是在课堂上和办公室里听过格雷厄姆说过很多遍。即便格雷厄姆从未以标准形式把它写下来,他也曾多次对身边最亲近的人表达过这一观点。”
6 In an exchange with some investors, Jason Zweig, a journalist with the Wall Street Journal, wrote the following about this famous phrase: “I called Warren Buffett and asked him. He, who knows Graham’s writings better than anyone else alive, was surprised when I walked him through the same two passages you cited. He had presumed, like many of us, that Graham had written these words. After a few minutes of thinking it through aloud, he realized that he might never have read the maxim after all, but rather that he had heard Graham say these words many times in class and around the office. Even if Graham never wrote them down in canonical form, he stated this view many times to those who were closest to him.
在我看来,那条流传最广的“短期是投票机、长期是称重机”格言,出自巴菲特而非格雷厄姆。在伯克希尔·哈撒韦的某份年报里(1987 年?说实话我不记得具体哪一份了),巴菲特用引号将这句名言归功于格雷厄姆。我相信这是目前能找到的最接近原始表述的形式。另一种可能性是,格雷厄姆的某位学生在 1930 年代初期价值投资课程保留下来的课堂笔记中记录下了这句话。我并未通读过所有笔记来确认这句格言是否在其中。但我认为这种可能性不大。在这件事上,我认为沃伦·巴菲特是无可置疑的消息来源,而且在我看来,结论已定:这话就是格雷厄姆说的,哪怕他从未写下来过。
In its most commonly cited form, I think the short-run-voting-machine-long-run-weighing-machine apothegm comes from Buffett, not Graham. In one of the Berkshire Hathaway annual reports (1987? I don’t remember which one, to be honest), Buffett attributes the maxim to Graham, in quotation marks. That’s the closest to their original form that I believe anyone will find them in. The only other possibility is that one of Graham’s students captured these words in some of the lecture notes that are preserved from Graham’s value-investing classes from the early 1930s. I haven’t read through them all to see if this saying can be found there. But I don’t think it’s likely. I regard Warren Buffett as an unimpeachable source in this case and, in my opinion, the case is closed: Graham said it, even if he never wrote it.”
请参见 http://www.bogleheads.org/forum/viewtopic.php?t=77840。
See http://www.bogleheads.org/forum/viewtopic.php?t=77840.
约塞夫·拉科尼肖克、安德烈·施莱弗和罗伯特·维什尼,《逆向投资、外推与风险》,
7 Josef Lakonishok, Andrei Shleifer, and Robert Vishny, “Contrarian Investment, Extrapolation, and Risk,”
《金融学刊》第 49 卷,第 5 期,1994 年 12 月,第 1541-1578 页;Chi F. Ling 和 Simon G. M. Koo,“论价值溢价,第二部分:解释”,《数学金融学刊》第 2 卷,第 1 期,2012 年 2 月,第 66-74 页。
Journal of Finance, Vol. 49, No. 5, December 1994, 1541-1578; Chi F. Ling and Simon G. M. Koo, “On Value Premium, Part II: The Explanations,” Journal of Mathematical Finance, Vol. 2, No. 1, February 2012, 66-74.
8 安德烈·施莱弗,《非有效市场:行为金融学导论》(英国牛津:牛津大学出版社,2000 年)。
8 Andrei Shleifer, Inefficient Markets: An Introduction to Behavioral Finance (Oxford, UK: Oxford University Press, 2000).
9 马克·鲁宾斯坦,“理性市场:赞成还是反对?支持方的观点”,《金融分析师杂志》,第 57 卷,第 3 期,2001 年 5 月/6 月,第 15-29 页。
9 Mark Rubinstein, “Rational Markets: Yes or No? The Affirmative Case,” Financial Analysts Journal, Vol. 57, No. 3, May/June 2001, 15-29.
延斯·卡斯滕·雅克沃斯与马克·鲁宾斯坦,《从期权价格中恢复概率分布》,
10 Jens Carsten Jackwerth and Mark Rubinstein, “Recovering Probability Distributions from Option Prices,”
《金融学刊》,第 51 卷,第 5 期,1996 年 12 月,第 1611–1631 页。精明(而且可能年纪较大)的读者会在这里发现一些关联。首先,鲁宾斯坦曾是一家名为 Leland O’Brien Rubinstein Associates, Incorporated 的公司的合伙人,该公司在 1980 年代提供投资组合保险服务。一些人认为,投资组合
Journal of Finance, Vol. 51, No. 5, December 1996, 1611-1631. Astute (and probably older) readers will make some connections here. First, Rubinstein was a principal at a firm called Leland O’Brien Rubinstein Associates, Incorporated that provided portfolio insurance in the 1980s. Some have argued that portfolio
保险加剧了 1987 年的崩盘。其次,鲁宾斯坦用数据证明了,在标准理论框架下发生这种崩盘的可能性微乎其微。最后,鲁宾斯坦探讨了理性市场理论。
insurance exacerbated the crash of 1987. Second, Rubinstein documented how unlikely a crash would be under standard theory. And finally, Rubinstein took up the case for rational markets.
11 Peter J. Tanous,《投资大师:全球最佳基金经理的致富路线图》(纽约:纽约金融学院出版社,1997 年),第 174 页。
11 Peter J. Tanous, Investment Gurus: A Road Map to Wealth from the World’s Best Money Managers (New York: New York Institute of Finance, 1997), 174.
12 Steven A. Ross,“新古典金融、另类金融与封闭式基金之谜”,《欧洲金融管理》,第 8 卷,第 2 期,2002 年 6 月,第 129–137 页。
12 Steven A. Ross, “Neoclassical Finance, Alternative Finance, and the Closed End Fund Puzzle,” European Financial Management, Vol. 8, No. 2, June 2002, 129-137.
安德烈·施莱弗与罗伯特·W·维什尼,“套利的局限”,《金融学刊》,第 52 卷,第 1 期,1997 年 3 月,第 35–55 页。
13 Andrei Shleifer and Robert W. Vishny, “The Limits to Arbitrage,” Journal of Finance, Vol. 52, No. 1, March 1997, 35-55.
14 Jack L. Treynor,“市场效率与豆罐实验”,《金融分析师杂志》,第 43 卷,第 3 期,1987 年 5 月/6 月,第 50-53 页。
14 Jack L. Treynor, “Market Efficiency and the Bean Jar Experiment,” Financial Analysts Journal, Vol. 43, No. 3, May/June 1987, 50-53.
15 Donald MacKenzie, An Engine, Not a Camera: How Financial Models Shape Markets (Cambridge, MA: MIT Press, 2006), 211-242.
15 Donald MacKenzie, An Engine, Not a Camera: How Financial Models Shape Markets (Cambridge, MA: MIT Press, 2006), 211-242.
16 Donald MacKenzie, “Models of Markets: Finance Theory and the Historical Sociology of Arbitrage,” Revue d’histoire des Sciences, Vol. 57, No. 2, 2004, 407-431.
16 Donald MacKenzie, “Models of Markets: Finance Theory and the Historical Sociology of Arbitrage,” Revue d’histoire des Sciences, Vol. 57, No. 2, 2004, 407-431.
17 詹姆斯·索罗维基,《群体的智慧:为何多数人比少数人更聪明,集体智慧如何塑造商业、经济、社会与国家》(纽约:双日出版社,2004 年)。
17 James Surowiecki, The Wisdom of Crowds: Why the Many Are Smarter Than the Few and How Collective Wisdom Shapes Business, Economies, Societies, and Nations (New York: Doubleday, 2004).
约翰·H·米勒与斯科特·E·佩奇,《复杂适应系统:社会生活计算模型导论》(新泽西州普林斯顿:普林斯顿大学出版社,2007 年)。
18 John H. Miller and Scott E. Page, Complex Adaptive Systems: An Introduction to Computational Models of Social Life (Princeton, NJ: Princeton University Press, 2007).
19 Scott E. Page,《差异:多样性的力量如何造就更好的团队、公司、学校与社会》(新泽西州普林斯顿:普林斯顿大学出版社,2007 年),第 208 页。
19 Scott E. Page, The Difference: How the Power of Diversity Creates Better Groups, Firms, Schools, and Societies (Princeton, NJ: Princeton University Press, 2007), 208.
20 Marshall K. Gramm 和 Douglas H. Owens,《跨投注池的同步赛马博彩市场效率》,《南方经济杂志》,第 72 卷,第 4 期,2006 年 4 月,第 926-937 页。 21 《本·格雷厄姆的遗产》,https://www.youtube.com/watch?v=m1WLoNEqkV4。
20 Marshall K. Gramm and Douglas H. Owens, “Efficiency in Parimutuel Betting Markets Across Wagering Pools in the Simulcast Era," Southern Economic Journal, Vol. 72, No.4, April 2006, 926-937. 21 “The Legacy of Ben Graham” at https://www.youtube.com/watch?v=m1WLoNEqkV4.
22 所罗门·E·阿什,《意见与社会压力》,《科学美国人》,第 193 卷,第 5 期,1955 年 11 月,第 31–35 页。
22 Solomon E. Asch, “Opinions and Social Pressure,” Scientific American, Vol. 193. No. 5, November 1955, 31-35.
23 这里有个花絮,讲给读注释的读者听。阿希在斯沃斯莫尔学院当教授时做了部分这类实验,还从附近的哈弗福德学院招募学生当受试者。其中一名学生是学习数学的杰克·特雷诺。特雷诺回忆说,他保持独立判断毫无困难。
23 Here’s a side story for endnote readers. Asch ran some of these experiments when he was a professor at Swarthmore College, and recruited students from nearby Haverford College to participate as well. One of those students was Jack Treynor, who was studying mathematics. Treynor recalls having no problem remaining independent.
24 S.E. Asch,“群体压力对判断的修正与扭曲效应”,载于 Harold Guetzkow(编),《群体、领导力与人类》(宾夕法尼亚州匹兹堡:卡内基出版社,1951 年),第 177-190 页。
24 S.E. Asch, “Effects of Group Pressure Upon the Modification and Distortion of Judgments,” in Harold Guetzkow (ed.), Groups, Leadership and Men (Pittsburgh, PA: Carnegie Press, 1951), 177-190.
25 约翰·梅纳德·凯恩斯,《就业、利息和货币通论》(纽约:哈考特-布雷斯出版社,1936 年)。
25 John Maynard Keynes, The General Theory of Employment, Interest, and Money (New York: Harcourt, Brace and Company, 1936).
26 Gregory S. Berns、Jonathan Chappelow、Caroline F. Zink、Giuseppe Pagnoni、Megan E. Martin-Skurski 和 Jim Richards,“心理旋转过程中社会从众与独立性的神经生物学关联”,《生物精神病学》,第 58 卷,第 3 期,2005 年 8 月,第 245-253 页。
26 Gregory S. Berns, Jonathan Chappelow, Caroline F. Zink, Giuseppe Pagnoni, Megan E. Martin-Skurski, and Jim Richards, “Neurobiological Correlates of Social Conformity and Independence During Mental Rotation,” Biological Psychiatry, Vol. 58, No. 3, August 2005, 245-253.
27 Sandra Blakeslee, “别人说的话可能会改变你看到的东西”, 《纽约时报》, 2005 年 6 月 28 日。 28 参见 https://www.youtube.com/watch?v=eAXVa__XWZ8。
27 Sandra Blakeslee, “What Other People Say May Change What You See,” New York Times, June 28, 2005. 28 See https://www.youtube.com/watch?v=eAXVa__XWZ8.
29 Steven H. Strogatz、Daniel M. Abrams、Allan McRobie、Bruno Eckhardt 和 Edward Ott,《理论力学:千禧桥上的行人同步现象》,《自然》杂志,第 438 卷,2005 年 11 月 3 日。
29 Steven H. Strogatz, Daniel M. Abrams, Allan McRobie, Bruno Eckhardt, and Edward Ott, “Theoretical Mechanics: Crowd Synchrony on the Millennium Bridge,” Nature, Vol. 438, November 3, 2005.
30 例如,参见 Momtchil Pojarliev(CFA)和 Richard M. Levich 的《外汇基金中的拥挤交易识别》(Detecting Crowded Trades in Currency Funds),《金融分析师期刊》2011 年 1 月/2 月号第 67 卷第 1 期,第 26–39 页。
30 For example, see Momtchil Pojarliev, CFA, and Richard M. Levich, “Detecting Crowded Trades in Currency Funds,” Financial Analysts Journal, Vol. 67, No. 1, January/February 2011, 26-39.
31 Blake LeBaron,“共同演化环境中的金融市场效率”,《社会代理人模拟研讨会论文集:架构与制度》,阿贡国家实验室与芝加哥大学,2000 年 10 月,阿贡 2001 年版,第 33-51 页。
31 Blake LeBaron, “Financial Market Efficiency in a Coevolutionary Environment,” Proceedings of the Workshop on Simulation of Social Agents: Architectures and Institutions, Argonne National Laboratory and University of Chicago, October 2000, Argonne 2001, 33-51.
32 来自塞思·卡拉曼 2008 年 10 月 2 日在哥伦比亚商学院的演讲。转载于《杰出投资者文摘》,第 22 卷,第 1 和第 2 期,2009 年 3 月 17 日,第 3 页。
32 From Seth Klarman’s speech at Columbia Business School on October 2, 2008. Reproduced in Outstanding Investor Digest, Vol. 22, Nos. 1 & 2, March 17, 2009, 3.
33 沃伦·E·巴菲特,“买入美国股票。我正在买入。”《纽约时报》,2008 年 10 月 16 日。
33 Warren E. Buffett, “Buy American. I Am.” New York Times, October 16, 2008.
34 这一分析来自史蒂文·克里斯特(Steven Crist),他在个人博客“Cristblog with Steve Crist”中撰写了关于三冠王角逐马匹的文章。他的第一篇博客题为“三冠王竞标”(2008 年 5 月 19 日),第二篇题为“三冠王数据”(2008 年 5 月 21 日)。我们更新了结果,将大布朗(Big Brown)和加利福尼亚铬(California Chrome)也纳入其中。克里斯特为《与最佳博弈》一书贡献了一个章节,这个章节可能不亚于巴菲特提到的那三个章节。该章节名为“克里斯特论价值”,非常清晰地阐明了价格与价值之间的区别。
34 This analysis comes from Steven Crist, who wrote about Triple Crown contenders in his blog, Cristblog with Steve Crist. His first entry was “Triple Crown Bids” (May 19, 2008) and the second, “Triple Crown Figs,” (May 21, 2008). We updated the results to include Big Brown and California Chrome. Crist contributed a chapter to the book, “Bet with the Best,” that may be worthy of the three chapters mentioned by Buffett. It’s called “Crist on Value,” and very clearly spells out the distinction between price and value.
35 Bruce C.N. Greenwald、Judd Kahn、Paul D. Sonkin 与 Michael van Biema 合著,《价值投资:从格雷厄姆到巴菲特及其后》(纽约:John Wiley & Sons,2001 年),第 35–43 页。
35 Bruce C.N. Greenwald, Judd Kahn, Paul D. Sonkin, and Michael van Biema, Value Investing: From Graham to Buffett and Beyond (New York: John Wiley & Sons, 2001), 35-43.
36 默顿·H·米勒与佛朗哥·莫迪利亚尼,《股息政策、增长与股票估值》,《商业期刊》,第 34 卷,第 4 期,1961 年 10 月,第 411-433 页。
36 Merton H. Miller and Franco Modigliani, "Dividend Policy, Growth, and the Valuation of Shares,” Journal of Business, Vol. 34, No. 4, October 1961, 411-433.