(b) Excessive withholding.--If the amount allowable as a credit for tax withheld from the taxpayer exceeds his tax to which the credit relates, the excess shall be considered an overpayment.

(c) Overpayment by employer.-- If there has been an overpayment of tax required to be deducted and withheld under section fifty-one, refund shall be made to the employer only to the extent that the amount of the overpayment was not deducted and withheld by the employer.

(d) Credits against estimated tax.--The administrator may prescribe regulations providing for the crediting against the estimated income tax for any taxable year of the amount determined to be an overpayment of the income tax for a preceding taxable year. If any overpayment of income tax is so claimed as a credit against estimated tax for the succeeding taxable year, such amount shall be considered as a payment of the income tax for the succeeding taxable year (whether or not claimed as a credit in the declaration of estimated tax for such succeeding taxable year), and no claim for credit or refund of such overpayment shall be allowed for the taxable year for which the overpayment arises.

(e) Rule where no tax liability.--If there is no tax liability for a period in respect of which an amount is paid as income tax, such amount shall be considered an overpayment.

(f) Assessment and collection after limitation period.--If any amount of income tax is assessed or collected after the expiration of the period of limitations properly applicable thereto, such amount shall be considered an overpayment.