今天，2010年5月6日，將是美國，甚至是世界，金融歷史上值得永遠記住的日子。今天股市崩盤，再一次演繹了1987年股市崩盤的偉大壯舉。下午2:30到3:00之間，整個股市在沒有任何跡象的情況下，突然大幅下跌。道瓊斯指數一度下跌倒9,869.62，和當日最高點10,879.76相差1000點有餘。標準普最低跌倒1,065.79，和當日最高點1,167.58相差200多點。納斯達克指數則最低下跌到2,185.75，和當日最高點2,407.79相差200余點，收盤時下跌3.44%。

從個股情況看，谷歌最低跌倒460，百度最低價位為625，收盤價為668。

通常而言被動起伏不應該很大的股票，像PG（開盤價61.91，最低39.37，收盤價在60.75）。IBM和可口可樂（KO）倒是沒有表演相同的瘋狂。那些有幸守株待兔事先下了固定價位訂單的投資者，可能有機會獲得跳樓價。而那些期望在瘋狂開始之後進入的投資者，要厶是你所在的券商服務器太忙，要厶是你被排在太后面，還沒有輪到你的時候，股價就已經開始大幅反彈。在我注意到谷歌460美元的報價之後，我下的470美元的訂單也沒有獲得任何的結果。很快看到的就是500美元的股價。蘋果公司也是一樣。

世界到底發生了什厶？人們為什厶如此　慌？世界末日到了嗎？從交易本身看，是因為幾個指數同時觸動了自動交易系統的開關。電腦系統開始自動出貨。在多數電腦系統同時自動出貨的時候，就是擁擠，就是恐慌，就是整個系統的混亂。

就投資本身看，有三股力量在左右股價的走向∶基本面，供求關係，人類的心態。

基本面決定了股價的長期價值；供求關係決定了正常情況下公司短期的股位；投資者的心態，則起到了放大股價波動幅度的作用。在牛市時，普遍的樂觀讓估值偏高，熊市時則相反，普遍的悲觀讓估值偏低，有時候是嚴重偏低。

除此之外，現在又出現了這個第四者∶電腦系統的激活。

對於這個系統的破壞性和不公平性，很快就應該有美國政府的關心了。這裡的不公平在於，普通的投資者基本上沒有參與的機會。你只能夠很被動的在那裡被人宰割而無任何自衛或者是反抗的力量。

從世界大局來看，最近歐洲政局不穩，希臘人在造反，造反的理由是需要“滿足造反者的條件”，無非就是在經濟方面不降低他們這些國民的待遇。按照面前的情況看，只有兩種辦法能夠解決希臘的問題∶其一是歐洲國家或者和美國聯合出手，在忽略貨幣的時間價值的情況下，也就是在以不計利息的情況下，大量借款給希臘這位世界的寵兒，讓他們繼續享受目前的生活水準；其二，就是希臘人自己開始反省和自救，開始改革，開始節儉度日，靠自己的勞動來還清過去幾十年奢侈過日子所欠的巨額債務。

希臘人的造反就在於，他們不想做這第二種選擇。至於自己欠他國的巨大債務，造反者的回答也很乾脆∶不知道，不在乎。

相比歐洲共同體而言，希臘的地位就像是美國的一個州。在一個州要破產的時候，美國納稅人有義務來救它嗎？更為糟糕的是，和美國州一級不允許搞赤字財政不同，希臘作為一個國家，還可以一直大舉借債度日，直到今天這種再也混不下去的時刻為止。

如果歐洲共同體救助這個奢侈的花花公子，那厶，下面會不會又更多的國家也想過不勞而獲的日子呢？如果他們那樣做了，那厶，你歐盟是不是還得再救呢？如果救了，那厶，對於那些勤勤懇懇過日子的老實歐盟盟民，是不是就是不公平的呢？

看來，歐盟的大麻煩在後面有的是。人性的貪婪就是造孽的根源。

影響更大的恐怕還是美元對歐元的持續升值，外加中國最近的政策異動。中國在加大力度抑制經濟過熱，打壓房地產市場的過熱。在世界經濟已經復甦的大前提下，似乎也是機會難得。但是，人算不如天算。緊靠美元的人民幣在美元對歐元持續貶值的時代，藉機也跟着貶值。中國企業得以有機會大量出口歐洲。現在，歐元對美元大幅貶值，掛靠美元的人民幣實際上也在跟着大幅升值。害怕人民幣升值打擊國內已經脆弱的出口業的中國學者，曾經有人計算過，如果人民幣升值一個百分點，中國企業的利潤會下滑多少個十位百分點的“學者”，不知道這時候是不是已經計算過，人民幣接近20%的對歐元升值，實際上到底意味着什厶？

如果歐元對美元繼續貶值，帶來的可能就是美國經濟復甦的困難了。在歐洲經濟已經出現困境的情況下，再拖累美國經濟，同時綁架中國經濟，結果可想而知。這才是為什厶，世界股市突然大幅跳水的原因吧。中國經濟的健康，還真的讓不少的人在牽掛着呢。這種感覺，可比二十年前自己來美國時，沒有人在乎中國人在怎厶樣過日子要強不少。這一次，人們和當時雷曼破產對市場的衝擊相比。如果這種比較是正確的，那厶，後續是不是就是新一輪的經濟危機呢？我自己覺得，可能性比較小。但是，又不能不防。世界之事，有太多的偶然性，事後再來回顧，那其中的必然性已經救不了我們了。

作為投資者，應該怎厶辦呢？

這種時候，小心建倉和進行投資對象的　度調整，可能是一件值得做的事情。期望看準底部，打賭大賺，估計是一件風險很大的事情。賭博這種事，在以身家性命為賭注的情況下，十次錯了一次，可能就是前功盡棄，一無所有。美國公司有很多在目前的價位不算高。長期而言還是會有不錯的投資回報結果，但是，如果你的資金是三五年需要使用的，恐怕也還是得保守一點為好。

更多介紹和分析，參閱我的新浪博客∶

http://www.blog.sina.com.cn/wangxiangusa

2010年5月6日星期四股指變化圖

附錄∶Look out below!

The market sees a major plunge, aided in part by computer programs designed to protect investors.

 Jim J. Jubak on Thursday, May 6, 2010 4:18 PM

Wow! Or, maybe better, Yeeouch!

In the last hour, the Dow Jones Industrial Average has been down 1,000 points as it fell and kept on falling. Or just 350 points down as it rallied off the bottom.

It closed near 10,500, off about 350, or a bit more than 3%.

My best guess on what's happening is that the selling of the last two days and the first part of today finally took prices on the major indexes low enough to trigger massive program trading.

In other words, as happened in the 1987 crash, computer programs designed to protect investors from massive losses by selling when prices got too low went into action and in selling created exactly the losses they were designed to prevent.

I'm using program trading here in the loosest sense for computerized trading programs designed to kick in at preset market conditions. I don't know -- and we won't know until someone takes apart the numbers after the close today -- whether the selling was triggered by the price of the actual indexes or by prices in the futures or options market.

As you'd expect on a day like today, gold has rallied -- back above $1,200 an ounce -- and safe-haven buying has taken prices of US Treasuries up and the yield on the ten-year note down as low as 3.33%, the lowest since December 2009.

Since, in my opinion, technical levels explain the huge plunge that took the Dow down 1,000 points or so (it's not clear what real stock prices were during the heaviest trading, since exchanges fell well behind on executing orders), let's look at some of the technical levels that might explain the selling.

Wednesday's decline left the Dow at 10,868. That was just above the Jan. 19 high at 10,725. Technical analysts that I read overnight were saying that the market was getting to a crucial test of the January high, but as long as the index closed above that level, investors were looking at a relatively minor correction in a trend that still pointed upwards.

But the gradual decline on Thursday took the index closer and closer to that key test at 10,725. At 1:38 p.m. ET the Dow broke below the Jan. 19 high, and the selling began to accelerate. By 2:30 the index was down to 10,596.And then all hell broke loose.

Selling fed on selling, and by 2:46 p.m. -- just a little over an hour after the index broke below the Jan. 19 high of 10,725 -- the Dow Industrials were down to 9,873.

Wednesday night, technical analysts had been pointing to the Feb. 8 low at 9,908 as the next test below the January high. Well, the index did get slightly below the February low -- by 35 points, to 9,873 -- but that marked the end of the free fall and the beginning of a rally that took the index back to a loss of around 350 points by 4 p.m.

Technical markers taketh away and then they giveth. At least for a few hours today.

Maybe technical levels of stock indexes did turn a bad day for stocks into a heart-in-your-mouth plunge, but stocks prices aren’t the only thing that might have triggered today’s 700-point drop in the Dow Jones Industrial Average from 2:30 to 2:46 p.m. ET.

There’s a good chance that the plunging euro played a part. The euro was down 1.5% against the dollar by 3:00 p.m. (roughly). That’s a drop of a full 2 cents and a bit more. That’s a big move since this market usually marks its gains and losses in the hundredths of a cent.

The euro’s plunge against the yen was even bigger, a huge 5.3% drop.

A 5% move in the currency market is almost a sure sign that somebody big has started to unwind, probably in hurry, a big, a big bet on the direction of currencies—and that other big players have followed suit.

One possibility that comes to mind is that someone was betting on the direction of the euro and using stocks or yen to hedge the risk. And when the euro went down to $1.2612 today that someone decided to unwind that hedge.

And it was the unwinding of that hedge that set the panic in motion.

A few minutes ago CNBC reported a trading floor rumor that the drop was a result of someone entering a trade in billions instead of millions. Could be.

But while the error may have started the ball rolling, it wouldn’t have turned into an avalanche without lots and lots of money blindly following price moves rather than paying attention to anything fundamental in the market.

If you think of stocks as interchangeable lottery tickets—and much of Wall Street does—this is the kind of trading day that results.