Why stocks go down on the ex-dividend date? (sell, exchange)

[novadude]

One of my stocks went down on the ex-dividend date, the date you need to own the stock in order to get the dividend.
Why would it go down on this date? Why would people sell? I don't understand, wouldn't they want the dividend?

[le roi]

What was the price action prior to this?

[LongArm]

There's no reason to keep a stock on the ex-dividend date because as long as you bought BEFORE the ex-date, you can sell first thing in the morning ON the ex-date and you'll still receive the dividend.

Also, the exchanges adjust the share price down by the amount of the dividend before the market opens.

[novadude]

Thanks Forgot about that.