A refund is a payment made by the state of California to the taxpayer when the amount of tax paid is greater than the amount of tax owed. In other words, if the taxpayer has overpaid their taxes, they will receive a refund. No amount due means that the taxpayer does not owe any additional tax and will receive a refund of any overpaid tax. In this case, the taxpayer does not have to pay any additional tax when filing their California Resident Income Tax Return.