How markets keep abreast of the news
市场如何跟上新消息的步伐
By Tim Harford 提姆 哈福德
Published: April 26 2008 01:24 | Last updated: April 26 2008 01:24
原文地址：
http://www.ft.com/cms/s/0/f046d35c-1009-11dd-8871-0000779fd2ac.html?nclick_check=1
Copyright The
Financial Times Limited 2008
翻译：fenglf 冯
If markets are efficient, you will never make profitable trades as a result of reading the Financial Times. Efficient markets move quickly and respond to any new headlines – disappointing earnings, a cut in interest rates, a fraud or a safety incident.
Markets will sometimes overreact, drifting backwards after a lurch, or underreact, taking time to digest the true impact of the new information – but overreactions and underreactions should balance out. And when no news is available, the prices of an efficient market won’t change much.
如果市场是有效的，那么你将不会因为读了金融时报就能做出什么有利可图的交易。有效的市场会快速反应任何新消息－－如令人失望的收益、一场欺骗或是安全的事情。市场有时候会反应过度，在单边倾斜后逐渐回复。市场有时候又会反应不足，需要花一些时间去消化新消息真正的影响。但是过度反应和反应不足常常会抵消掉。当没有有效的新闻的时候，一个有效市场的价格就不会有多大的变化。
But do markets really react efficiently to news? It would be easy to tell if it were easy to identify all genuine news. Sadly, it is not. Yet two inventive new academic papers claim to have solved the problem of identifying news, in two very different contexts. The studies could not be more unalike. One looks second-by-second at trading data from one of the world’s most active financial exchanges. The other analyses market information that is more than two centuries old.
但是市场真的能对新信息作有效的反应吗？如果能很容易的识别所有真实的新信息那也就简单了，遗憾地是，这不可能。然而两篇新近的有创造性的学术论文声称他们找到了解决新信息鉴别问题的办法。两篇论文是两种非常不同的分析脉络，这研究不可能再更加地不一样了。其中一篇论文仔细观察了一个全球最活跃的金融交易所的交易数据。另一篇则分析了两个世纪前的市场信息。
Karen Croxson and J. James Reade of Oxford University studied the Betfair exchange, a sports betting site that supports many more trades than the London Stock Exchange. Betfair allows punters to bet on football games, and the market stays open throughout the match. Croxson and Reade studied how the price of different bets varied as goals were scored during English league games.
牛津大学的Karen Croxson 和J. James Reade 研究了必发(Betfair)博彩交易所，这是一个支持比伦敦股票交易所更多种交易方式的体育博彩站点。必发(Betfair)允许赌徒们对足球比赛下注，并且其下注窗口在比赛的整个过程中都始终打开。Croxson和Read研究了英超比赛期间不同赌注的价格是如何随着进球数的变化而变化的。
This is an excellent test of the market’s response to news: the bets have a clear value at the end of the game, goals are scarce and important events – and (unless one is a referee) they are easy to spot. And the stakes are not trivial: hundreds of pounds a second are wagered during the match.
这是一个极好的市场对新消息反应的试验：下的注在比赛结束后会有一个清楚的价值，进球是稀缺的也是重要的，并且很容易数出。赌注不是问题，比赛时，每一秒钟数以百计的英镑被下注。
The idea of using sports betting to test market efficiency came from Steven Levitt (the co-author of Freakonomics) and Ricard Gil. Levitt and Gil had conducted an earlier study in rather thinner betting markets, and found that prices jumped immediately after a goal, but they then drifted further in the same direction. Was that because the traders were sluggishly digesting news of the goal? Or was it because the clock was ticking down, no news being good news for the team in front? Croxson and Reade offer a clever answer, by looking at those goals scored just before half time. Relevant news hardly ever emerges during half time and the pair find that, although trading is active during the break, prices barely move at all. This shows that the market traders instantly absorb the news of a goal. After the second half begins, prices start to drift again, just as Gil and Levitt found.
用体育博彩来测试市场有效性的想法来自Steven Levitt (魔鬼经济学的合作者) 和 Ricard Gil。 Levitt和Gil在很早就在一个相当小的赌博市场做了研究，并且发现价格在进球后立即开始变化，但是之后价格却在同一方向波动的更远。这是因为交易者们对进球的消息反应很迟钝吗？或者是因为当比赛还没结束时，就球队来说没有新闻就是好消息？Croxson和Reade通过只观察上半时的进球记录得到了一个聪明的答案：相关的消息几乎不会在中场休息时出现，两位发现，尽管交易在中场休息仍然很活跃，但是价格却几乎没有变动。这表明市场交易者立即消化了进球的新消息。当下半场开始后，价格又开始波动，如Levitt和Gil发现的。
That suggests an efficient response both to news and to the absence of news, in sports betting markets at least.
这表明了一个对新消息或者没有消息的消息的有效反应，至少在体育博彩市场是如此。
But Peter Koudijs of Barcelona’s Universitat Pompeu Fabra has a different perspective. He looked at prices of three English stocks (the East India Company, the Bank of England and the South Sea Company) on a secondary market in Amsterdam from 1771 to 1777.
但是巴塞罗那庞培法布拉大学的Peter Koudijs有不同的看法。他观察了阿姆斯特丹一个中级市场的三只英国股票(东印度公司、英格兰银行和南海公司)从1771年到1777年的价格变化。
Koudijs realised, and proved, that relevant news flowed almost exclusively from London to Amsterdam – and always through the same channel, a boat sailing across the North Sea bringing market data to Amsterdam. Depending on wind speed and direction, the “packet boat” might arrive promptly or after a delay of more than a week, occasionally starving the Amsterdam market of news for days on end.
Koudijs认识到并证明，那些相关的消息几乎都是通过单一渠道从伦敦流向阿姆斯特丹的，并且总是从同一渠道，即由携带有市场信息的船穿过北海到达阿姆斯特丹。由于风的速度和方向的变化，“邮船”可能很快达到或者是超过一周的延迟，偶尔也会永远没有到达。
Koudijs discovered that when the wind was unfavourable and no news was available, Dutch prices for these English companies were highly volatile anyway. That is not an efficient market.
Koudijs发现当风势糟糕，没有什么有效信息的时候，这几个英国公司的在荷兰市场的股票价格就会极不稳定。这不是一个有效市场。
So, have we discovered something uniquely inefficient about Dutch markets, or something uniquely efficient about sports betting? I am not sure. An analysis of Dutch football games is the logical research extension.
那么，我们是不是发现了一些关于荷兰市场的独特的无效性？或者是一些关于体育赌博市场独特的有效性？我不能确定。对荷兰足球市场的分析应该是合逻辑的研究延伸的方向。
请大家看看有下划线句子 帮忙翻译一下 搞不定那几句 谢谢
