What was the ESH08 close on Fri.?!

I'm showing the close on Fri. as 1335.75 when using day trading hours and then on the daily charts using exchange hours it is showing the close as 1331.25?!
which was it anyways?
my statement is also marked to the latter!

 

On the last day of the month, stock index futures contracts settle at "fair value".

 

1331.25

 

I'll be damned and severely embarrassed...! 20+years into trading and never knew this.
thanks

 

and worst, had I known this I would have gone all short on Fri. knowing that it'll most probably open 4 points lower on Sun.
or if this happens during the weekdays, a great advantage could be got from it?! has anyone been using this feature?

 

There's no "edge" with it. If you're "leaning" the correct way on the last day of the month, your statement will look better but the market will correct the next session.

 

I don't trade futures so I have a question about this -
Fair value is what the index actually ended as am I correct?

 

it got adjusted to the fair value after the close.

 

Fair value settlement at month end is the cash index plus the calculated futures premium. For a complete explanation of stock index futures fair value go to www.indexarb.com .