受到保时捷2009年将会继续增持股份直到75%消息的刺激，德国大众汽车公司（Volkswagen AG）的股价在2天之内狂飙了四倍多，其市值瞬间超过埃克森美孚而跃居全球第一。同时，大众股价的飙涨还带到德国DAX指数上涨11%，并刺激了美国投资者纷纷入市抢便宜货，美国道琼斯指数周二也狂飙了11%。

之所以为出现这种不可思议的情况，乃是因为此前外界预测保时捷增持越过50%的界线后将会停止增持动作，一些机构见此情景料定Volkswagen已无上涨潜力，许多对冲基金对Volkswagen进行了裸卖空。保时捷的增持消息一公布，意味着未来大众将只有6%的流通股可供交易，这使得卖空机构一时恐慌至极，纷纷不顾一切高价回补自己的头寸，这才导致Volkswagen股价出现这样奇迹般的一幕。

这件事情至少说明以下几个问题：一是盲目地裸做空存在很大的风险。特别是趋势投资者，在连续的市场下跌过程中，如果持续做空，市场反转后，就会死会葬身之地。危机发生后，西方各国股市的波动性空前增大，类似的逼空行情，说不定还会在其它个股上面上演。

二是产业资本对金融资本的平衡作用不可忽视。保时捷作为产业资本，对Volkswagen的评估有自己的标准，而金融资本，往往善于玩虚的，往往喜欢跟风，增加产业资本在市场上操作的便利，可以起到平衡金融资本力量畸大的作用，对市场稳定有积极作用。

三、对国内投资者来说，由于即将引进融资融券交易，类似情况未来也可能出现。融资是高风险，特别是牛市末端；融券同样的是高风险，特别是在熊市末端。

学习资料: When Stock Short Sellers get the Squeeze

Sometimes during a volatile stock market, especially after a series of dramatic down closings, you’ll see an equally dramatic rebound in key indexes.

This may last just one day before the market slips back to its slide, but it leaves some investors scratching their heads.

What may be happening is a short-seller squeeze.

Short sellers are traders who sell a stock they don’t own anticipating it is going to drop in price.

Stock Drops in Price

If the stock does drop in price, the short seller buy the stock back at the lower price and replace the borrowed shares.

The difference (less commissions, etc.) is their profit.

For example, if the trader believes stock X is going to drop she borrows the shares from her broker and sells them at the current market price of $50 per share.

When the stock does fall to $40 per share, the trader buys the shares on the market and replaces them with her broker, pocketing $10 per share profit (less commissions, etc.)

For a complete explanation of short selling, check out my article.

Stock Rises

If the short sellers have guessed wrong and the stock rises, they are then in a losing position.

Using our example above, instead of falling to $40 per share the stock rises to $60 per share.

Now, the trader must buy the shares at $60 to cover the shares she sold at $50 per share.

Our trader has lost $10 per share (plus commission, etc.). We hope she would have closed out her position before facing a $10 per share loss.

Stocks Unexpected

When short sellers bump into a market that does the unexpected, they may be looking at the same situation as our example.

If share prices rise unexpectedly, especially in a market that was looking like it should keep going down, short sellers may panic and close out their positions.

As short sellers begin buying to cover their shorts, it may push the market and other stocks up creating an even worse situation for the speculators.

Short sellers don’t get a lot of respect on Wall Street – after all, they are betting on failure or at least bad news to win.

I don’t consider them investors because their time horizon is short term.

Short selling is a risky game and not one you should play unless you know what you are doing. Never play it with money you can’t afford to lose.