allowable distribution period
(2) Allowable distribution period The term “allowable distribution period” means, with respect to any private foundation, the period beginning with the first day of the first taxable year following the taxable year in which the incorrect valuation (described in subsection (a)(2)) occurred and ending 90 days after the date of mailing of a notice of deficiency (with respect to the tax imposed by subsection (a)) under section 6212 extended by— (A) any period in which a deficiency cannot be assessed under section 6213(a), and (B) any other period which the Secretary determines is reasonable and necessary to permit a distribution of undistributed income under this section.