Balance on the date of withdrawal for Net Income Attributable calculation for excess contribution withdrawal.

Hi,

 

To calculate Net Income Attributable, I need to know the balance on the date of withdrawal.

If I am submitting my request for withdrawal in the morning of a trading day, the balance will likely not be the same by the end of the day.

 

How is one supposed to handle this? Wait for the market to close and then submit the request (I don't want to do this because I'm already cutting it close to the tax deadline).  or do I use the balance at the close of the previous day i.e. the balance before the market opens that day?

 

Thanks in advance!