The rumor being passed around by several sources is that Facebook won’t be filing its IPO until this afternoon according to All Things D. This means that the filing will take place after the markets close. A major bummer to all those hoping to jump on the big money bandwagon.

Why is it taking them so long? Sources are saying that the company is taking its time filing the papers. These things take time and Facebook wants to make sure that they make a good first impression like Zynga and Google before them.

If we’re lucky, we could see the details of the IPO early today. The problem with luck is that it is hardly ever on our side. Facebook is holding all the cards and they will reveal their IPO when they’re ready.

As we reported yesterday, the IPO could be worth $5 billion when it’s unveiled. You can bet that it will be valued much higher though. Facebook is too big to start out that small.

This is all just mere speculation though until we get the actual numbers. If Facebook files today, we’ll have all the gritty details for you. If they file tomorrow or even later, we’ll still be here watching out for the elusive Facebook IPO.

This is the biggest IPO so far this year and with Twitter not even considering an IPO yet, Facebook has all the time in the world.