ABSTRACT. Banks often demand greater levels of excess balances when flows in and out of their accounts are in greater volumes, and thus a greater uncertainty attends their end-of-day balance. Beccalli et al. use the natural log of total assets as a proxy of the influence of bank size. Carpenter and Demiralp note that, beginning in January 2004, banks were allowed to adjust the level of contractual clearing balances each maintenance period, but the level may not be adjusted within a maintenance period.