[Follow The Trend]

While there are a lot of good comments above, I am not sure it is really as straight forward as some think.

I agree that the first stock price of the day reflects the perceived demand for the stock at the open, and perhaps a little bit of completing orders from the day before. However, it is a little simplistic to say that the closing price is so predictable, because there are many factors to consider.

A lot can happen to the momentum of a stock from start to close.