My credit union offers a savings plan that pays daily interest for just this type of situation, but offers only 1.15%, as opposed to the regular savings rate of 2.55%. So depending on how often money will be withdrawn, either of these types of plans would work, or maybe a combination of them both. If there will be frequent, smaller withdrawals, then that should come from the special savings plan (called a Plan 24 in my case), so that interest for the month is not lost, and more infrequent withdrawals could come from the regular account where interest is paid monthly.