Why is SPY trailing the SP500 Index

As I write this (11:40 am PT, 12/20/13) according to YAHOO finance the SPY is up today 0.22% but the SP500 Index is up 0.73%. I've never seen such a big difference. What's up? Did the arbs all go on vacation already?

 

That happens on a regular basis, same with the DOW/DIA and Nasdaq/QQQ

 

dividend

 

Duh. Thanks!

 

love this answer, when the real answer is SPY is ex dividend today. FXforex you don't stay on top of news/anything very much do you?

 

24 hours later: Is SPY above or below the futures? Is the difference still equal the dividend? If no, why?

 

Does any one know why SPX performance is trailing SPY performance?

SPX is up 29% for the year, but SPY is up 32%.

 

Better check your numbers.

SPY was up 29.69% and SPX was up 29.60%.

 

SPY includes the dividends

 

Two reasons:

1. S&P 500 is traded from 9:30 until 16:00. SPY may trade after the market close. If after the market close SPY went strongly up/down, you will have big divergence on the next trading day between SPY and the S&P 500.

2. SPY may ave paid dividends. On the and following days tou may have strong divergence.

At the end in both cases the SPY and the S&P 500 are aligned.