SWIFT/MT940: How can the closing balance date be determined when MT940 reports arrive in multiple pages and sequences around midnight?

This is something you will have to assign and adhere to. With our clients, the date is set at the last transmission. In some cases, we have seen clients use the start of transmission date to be the settlement/closing balance date. It honestly, depends on how you follow it. Setting a midnight cut-off date works for some and not for others.