§ 7473. Allocation of payments
Any payment received by the Commissioner from any taxpayer with respect to a tax liability of the taxpayer may be applied to any tax liability in the following order of priority, notwithstanding any direction by the taxpayer to the contrary:
First, against any portion of any tax liability initially incurred with respect to a preceding taxable year, with the portion incurred with respect to the earliest preceding taxable year to be satisfied before any portion incurred with respect to any succeeding taxable year; next, against any portion of any tax liability incurred with respect to the current taxable year. As to each portion, the payment shall be applied, first, to the amount of any interest; next, to the amount of any penalty; next, to the amount of any fee; next, to the amount of any unpaid tax; incurred with respect to the taxable year. (Added 1969, No. 269 (Adj. Sess.), § 1, eff. date, see note under § 7401 of this title.)