27 C.F.R. § 40.523
Every manufacturer of processed tobacco must provide a true and accurate inventory on TTB F 5210.9 in accordance with instructions for the form. The manufacturer must make such an inventory at the time of commencing business, at the time of transferring ownership, at the time of changing location of the factory, at the time of concluding business, and at such other time as any appropriate TTB officer may require. In the case of a manufacturer operating under the transitional rule set forth in §40.493, that manufacturer must make an inventory within 10 days of the date of TTB's written acknowledgement of the receipt of the application filed under § 40.492 . Each such inventory is subject to verification by the appropriate TTB officer.
27 C.F.R. § 40.523
26 U.S.C. 5721