How hard is the short side? Take this morning. Right from the get-go, all of these silly Linux-related companies take off because of the

Justice Department's

plan to break up Microsoft. They are all up three and four points. Of course, these companies have very little in the way of fundamentals. They seem to go up solely as a function of whether Joel Klein growls or not.

So we figure, what the heck, let's sell some of the Linux-related stocks

short. But before we can do that, we have to get a "locate" -- meaning we have to identify where we can get some shares to deliver as part of the short-selling mechanism. If we can't borrow the shares, when we sell them we won't be able to deliver them. (Even if you sell short, you still have to deliver those shares to the buyer. You have to borrow them.)

We look -- and there are no shares that can be borrowed. They are all let out ahead of us. So we can't short the stocks. We can't find them to borrow to send!

So the trade doesn't get done. You can't short what you can't borrow. Period.

James J. Cramer is manager of a hedge fund and co-founder of TheStreet.com. At time of publication, his fund was long Microsoft. His fund often buys and sells securities that are the subject of his columns, both before and after the columns are published, and the positions that his fund takes may change at any time. Under no circumstances does the information in this column represent a recommendation to buy or sell stocks. Cramer's writings provide insights into the dynamics of money management and are not a solicitation for transactions. While he cannot provide investment advice or recommendations, he invites you to comment on his column at

jjcletters@thestreet.com.