This depends on the means by which you have imported your account statements.
BudgetView manages two key import formats:
If your bank only offers a QIF or CSV export and no balance information was previously available in the application, BudgetView will not show any balance after your first import.
Should this be the case, you will have to click on the account balance in the "Accounts" view, then enter the last known balance. Subsequently, BudgetView will automatically update this balance with successive imports, following transactions made.