Date of allowance of refund or credit.
The date on which the appropriate TTB officer, first certifies the allowance of an overassessment in respect of any internal revenue tax imposed by the provisions of 26 U.S.C. enforced and administered by the Bureau shall be considered as the date of allowance of refund or credit in respect of such tax.
26 U.S.C. 6407
[T.D. ATF-301, 55 FR 47616, Nov. 14, 1990, as amended by T.D. ATF-450, 66 FR 29025, May 29, 2001]