I found out the hard way that Citibank when they put a hold on funds processed by credit/debit until they clear (say I bought a candy bar for $1.50) they do not

I found out the hard way that Citibank when they put a hold on funds processed by credit/debit until they clear (say I bought a candy bar for $1.50) they do not pay out of those funds. They release the funds back into the account, where if I was 1 cent short they would charge an overdraft even though the day before they were holding those funds which I thought innocently would go to pay for the candy bar. The good news now even though they send me overdraft notices they stopped charging the overdraft fees for at least this type of transaction.