That vicious end-of-the-day crunch had to do with a massive sale of

Spiders

and

QQQs

, indices meant to track the

SPX

and the

Nasdaq

respectively.

It's amazing what the bull has to put up with, at the end of the day, isn't it? If it's not daytraders blowing out of stock in order not to run afoul of margin rules (some of them own stock intraday worth many, many times their capital, a clear but hard-to-prove violation, because it's so hard to know what people are up to between 9:30 and 4:00), it's program traders blasting the market to smithereens with these derivatives.

It would be difficult for the market to fend off the kind of compression it got today if the sell programs happened at 2:30 instead of 3:30, or 3:45 like this one. At least, however, during the middle of the day, companies with big cash flow can stand there and buy back stock to take the sting out of the programs. Nobody, however, is allowed to be buying in the last half hour, so the market is at the mercy of these Quick-Draw sellers.

I usually like to take advantage of the compression, but there was no opportunity today as the programmers performed their evil magic right to the close. Oh well, we will have to wait until tomorrow.

James J. Cramer is manager of a hedge fund and co-founder of TheStreet.com. At time of publication, his fund had no positions in any stocks mentioned. 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.