Short Term Trading Week Starting: 23 Jan, page-75

Hey STT'ers,

Here is a question for the crowd. Probably a newbie question, but I would like to know anyway.

I had a order in for a stock that was partially filled at 3:59 today (it was the last trade of the day). At auction the stock traded at the same price at it did for my partial fill and traded multiple units post 4:00pm that would have comfortably completed my fill. However, upon looking later nothing was filled at all, even though I was partially filled and first in the que at close.

Can someone tell me what the situation is here and why other were filled before me?