What happened today? S&P down 7.5%

Today's fall was unexpected, and ruined my projections for the next few days.

The week was shaping up to look very much like the post-9/11 week, which featured a vacillating, downward-trending market but no real climax selling days. Then the following Monday jumped 5%.

Another possible analogue, though, was the week before the October 1987 crash. That week did have one up day before selling built up on Friday, which was down 5%, and led to the Monday debacle.

It was looking like Friday could have been a 7% down day, and Monday a rebound. But now that it happened on a Thursday, I'm not sure what to make of the weekend.

Tomorrow—Friday—could be another rebound day. The market has had so many losing days in a row there is going to be an upward pop soon. But it might have to wait until Monday. If so, what tomorrow? Probably another zig zag day that ends slightly lower, and a big jump on Monday.

But tomorrow could be really bad, too. There hasn't been such a huge Thursday drop in the last 20 years. Not sure what it means, but unless tomorrow's up big I'm ready to jump in with S&P options. Last time I was foiled when the market opened much higher instead of selling off in the morning. I think people are wise to the fact that big up days follow the big 7% down days.

We'll see if it happens again tomorrow. If not, Monday should be very strong.