Ooops + Moooo = Weeee

Those who do not follow the stock market much might not have noticed an unusual occurence yesterday. The market was down modestly most of the day. Then, all of the sudden and in the final minutes of trading, the stock markets popped up like a cork released under water. Why?

Here's a five minute chart of the market from yesterday. Note the pop at the end of the day:



Quite unusual.

Barry Ritholz thinks he now knows why. Turns out someone made an "error" in an earlier trade and needed to "unwind" that error by buying at the end of trading.

Oooops.

That set into motion a number of reactions by other traders, often using computer programs to determine when/what to buy/sell. The result? A market swing of 200 points in a matter of a few minutes.

Mooooooooo

Gives you some insight into how tricky and crazy the stock market is on any given day.