27 CFR § 70.71 - Assessment authority.
The appropriate TTB officers are authorized and required to make all inquiries necessary to the determination and assessment of all taxes imposed under the provisions of 26 U.S.C. enforced and administered by the Bureau. The appropriate TTB officers are further authorized and required to make the determinations and the assessments of such taxes. The term “taxes” includes interest, additional amounts, additions to the taxes, and assessable penalties. The authority of the appropriate TTB officers to make assessment includes the following:
(b) Unpaid taxes payable by stamp.
(1) If without use of the proper stamp:
(i) Any article upon which a tax is required to be paid by means of a stamp is sold or removed for sale or use by the manufacturer thereof, or
(ii) Any transaction or act upon which a tax is required to be paid by means of a stamp occurs, the appropriate TTB officer, upon such information as can be obtained, must estimate the amount of the tax which has not been paid and the appropriate TTB officer must make assessment therefor upon the person the appropriate TTB officer determines to be liable for the tax. However, the appropriate TTB officer may not assess any tax which is payable by stamp unless the taxpayer fails to pay such tax at the time and in the manner provided by law or regulations.
(2) If a taxpayer gives a check or money order as a payment for stamps but the check or money order is not paid upon presentment, then the appropriate TTB officer shall assess the amount of the check or money order against the taxpayer as if it were a tax due at the time the check or money order was received by appropriate TTB officer.
The following state regulations pages link to this page.