26 C.F.R. § 1.547-1
Section 547 provides a method under which, by virtue of dividend distributions, a corporation may be relieved from the payment of a deficiency in the personal holding company tax imposed by section 541 (or by a corresponding provision of a prior income tax law), or may be entitled to a credit or refund of a part or all of any such deficiency which has been paid. The method provided by section 547 is to allow an additional deduction for a dividend distribution (which meets the requirements of this section) in computing undistributed personal holding company income for the taxable year for which a deficiency in personal holding company tax is determined. The additional deduction for deficiency dividends will not, however, be allowed for the purpose of determining interest, additional amounts, or assessable penalties, computed with respect to the personal holding company tax prior to the allowance of the additional deduction for deficiency dividends. Such amounts remain payable as if section 547 had not been enacted.
26 C.F.R. §1.547-1