27 CFR § 19.465 - Shortages of bottled spirits.
(a) Determination of shortage. The determination of whether an unexplained shortage of bottled distilled spirits exists must be made by comparing the spirits recorded as being on hand to either the results of the physical inventory required by § 19.372 or the results of any other complete physical inventory taken by the proprietor. When the recorded quantity is greater than the quantity determined by physical inventory, the difference is an unexplained shortage. The proprietor must adjust its records to reflect the results of the physical inventory.
(b) Payment of tax on shortage. A proprietor must pay the tax on any unexplained shortage of bottled distilled spirits:
(1) Immediately on a prepayment return on form TTB F 5000.24, Excise Tax Return; or
(2) On a deferred payment return on TTB F 5000.24 for the period during which the shortage was determined.