How do I determine the aggregate maximum account value of my non-U.S. financial accounts?

How do I determine the aggregate maximum account value of my non-U.S. financial accounts?

First, determine the highest amount of each account for the relevant year.  This is the high-water mark of the account, ie the max amount that you have held in the account at any point during the year, even if just for a second.  It doesn’t matter how much money ran through the account during the year; we only need the number representing the highest amount of money in the account at any one time during the year.  If you cannot determine the exact maximum account value, you can use a reasonable approximation based on the best available records. Also note that you can also choose to report that the maximum account value is unknown.