【英语科技】如何利用股市动荡赚钱？

So this is the way the quarter ends: not with a whimper but with a bang.

First investors had their hair set on fire by the 'flash crash' of May 6. Then came the jolt of June, as stocks lost another 5.2% and finished the month with five down days in a row.

As usual, the markets made a monkey out of anyone who had been certain about what had to happen next.

Europe is in worse shape than the U.S., said the consensus this spring-and, right on cue, European stocks outperformed the U.S. market sharply in June. Treasury securities, legions of experts declared earlier this year, were doomed to lose money-and promptly boomed, with long-term U.S. government bonds gaining 8% last month and 23% year-to-date. And even as the housing market faltered again, real-estate stocks did slightly better than U.S. equities overall.

Meanwhile, volatility burst back onto the scene. The widely followed 'fear gauge'-the CBOE Volatility Index, or VIX-nearly tripled from April to May, after a long decline from the jagged days of late 2008 and early 2009. After falling back in early June, the VIX spiked again in the final days of the month.

Investors have taken note. On June 30, according to IndexUniverse.com, iPath S&P 500 VIX Mid-Term Futures, which tracks futures contracts on the volatility index, was the fastest-growing exchange-traded product in the country. It grew by 25% on that day alone, taking in $128 million from investors hoping to profit from the spike in turbulence. The iPath instrument has returned 9% over the last month and was up 46% in the second quarter, according to Morningstar, the investment-research firm.

Meanwhile, although figures aren't in yet for June, trading activity by clients at Charles Schwab was up 17% in May from April-which, in turn, was up 12% over March. At TD Ameritrade, the average number of daily transactions has grown at about 14% over the same period. 'There are more people trading,' says Jay Pestrichelli, a managing director at TD Ameritrade, 'and there are more people trading options to try to take advantage of volatility.'

Before you join the crowd trading on turbulence, there are a few things you should know.

First, while volatility provides a close mirror image of current returns, it is a poor forecaster of future returns. Robert Engle, a finance professor at New York University who shared the 2003 Nobel Prize in economics for his research on volatility, warns that 'there really isn't any predictability in that direction.' He explains, 'Even though volatility tends to be high in bad markets, that doesn't mean the market is going to keep going down-it just means the market has been going down.'

Prof. Engle adds that periods of high-or low-turbulence don't persist indefinitely. 'When you're in a stormy period, there is a tendency for the storm to end,' he says. 'But it's not a very strong effect, and it can take a long and uncertain time.' It is possible to forecast volatility 'in general,' says Prof. Engle, 'but there's a lot of uncertainty around those forecasts.'

In short, 'volatility has a volatility of its own,' says finance professor Robert Schwartz of Baruch College at the City University of New York. That is precisely why the prices of the various products based on the VIX vary drastically over time.

Just as you are likely to add earthquake coverage to your insurance policy after-but not before-the ground has been shaken, the VIX typically goes up as stocks go down, and vice versa.

Investors have a chronic habit of chasing any asset that rises and fleeing it when it falls, even though they should become less willing to buy into whatever grows more expensive and more eager to pick up whatever gets cheaper. (Just think of how much happier you were to hold stocks three years ago than you are today.) The surging interest in trading on turbulence seems to be working much the same way. As volatility has become more costly to 'own,' more people want to buy it. When it was cheaper, it went begging.

There is little doubt that adding some volatility insurance to your portfolio is a good idea. But the time to do so is when most other investors have no interest in it-not when it is in the midst of a sudden burst of popularity. If you want to capitalize on volatility, wait until markets are calm, not stormy, and the prices of the various VIX products come down. Right now, Prof. Engle says, 'it's insurance, but it's gold-plated insurance.'

第二季度就这样结束了，不是悄无声息，而是砰的一声。

首先是5月6日投资者被电闪雷击烧焦了头发，然后是令人震惊的6月，股市再下跌5.2%，以连续五个交易日下挫结束6月份。

Christophe Vorlet一如往常，市场再次愚弄了那些对未来走势有把握的投资者。

市场今年春天时一致认为，欧洲股市将比美国股市差，然而6月欧洲股市远优于美国。今年稍早专家们认为的集团军──美国国债注定要赔钱，但美国国债很快上涨，美国长期国债上月涨8%，年初至今累计升23%。即使地产市场再次走软，但地产类股表现略优于美国整体股市。

与此同时波动性再次受到关注。广受追踪的“忧虑指标”──芝加哥期权交易所（CBOE）波动性指数（VIX）从4月至5月几乎上升了两倍，而在2008年底至2009年初一直为下降。在6月初下降后，波动性指数在6月的最后几天再次上升。

投资者一直在关注着。根据IndexUniverse.com，iPath 标准普尔500波动性指数中期期货（iPath S&P 500 VIX Mid-Term Futures）仅6月30日当日就上涨25%，从那些希望从股市震荡幅度下降中获利的投资者那里赚取了1.28亿美元。根据投资研究机构晨星数据，该iPath工具上月回报率为9%，第二季度累计涨46%。iPath 标准普尔500波动性指数中期期货追踪波动性指数期货合约，是美国成长最快的交易所交易产品。

尽管目前还没有6月份数据，但5月客户在嘉信理财（Charles Schwab）的交易量较4月增长17%，4月较3月交易量上升12%。在TD Ameritrade，同期内日均交易量上升约14%。TD Ameritrade董事总经理佩斯特里彻里（Jay Pestrichelli）说，交易的人更多了，还有更多人交易期权，因为他们想利用波动性获利。

在你加入蜂拥的人群利用股市的动荡而交易时，有几件事你应该知道。

首先尽管波动性彰显了当前的回报率，但它不能很好地预测未来回报率。纽约大学金融学教授恩格尔（Robert Engle）警告说，在方向上没有什么可预测性，尽管市况不佳时波动性较高，但这不意味着市场将继续下跌──它只意味着市场过去一段时间在下跌。恩格尔由于对波动性的研究，和别人分享了2003年诺贝尔经济学奖。

恩格尔教授补充说，市场不会无限期持续较高或较低的动荡。他说，当你处于一个风暴期时，风暴有可能结束，但不会有很强的效果，风暴会持续很长且不确定的一段时间。总体来说可以预测波动性，但在这些预测因素内有很多不确定性。

纽约市立大学巴鲁克学院（Baruch College at the City University of New York）金融学教授施瓦兹（Robert Schwartz）说，简言之，波动性有它自己的波动性，它准确地说明了基于波动性指数的各种产品价格为什么差异这么大。

这就像你可能会在地震后将地震险纳入你的保单一样，而不是地震前，地面已在震动，波动性指数通常随着股市下跌而上升，反之亦然。

投资者习惯于追涨杀跌，尽管他们应该在涨价时尽量减少买入，而在价低时更多买入。（设想一下如果你三年前就持有股票，而不是现在，那你该更高兴了。）因股市动荡而交易兴趣上升似乎也是同样的情况。由于拥有波动性的价格更高，因此更多人希望买入。当波动性价格下跌时，就会销路极差。

毫无疑问将一些波动性保险纳入你的投资组合是个好主意，但这样做的时机是其他多数投资者没有兴趣的时候，而不是其突然受到关注的时候。如果你想在波动性上获利，那就等待市场降温，各种波动性指数产品价格下跌。恩格尔教授说，它是保险，但它是镀过金的保险。