Vt. Stat. Ann. tit. 32, § 8907

(1) The Commissioner may investigate the taxable cost of any motor vehicle transferred subject to the provisions of this chapter. If the motor vehicle is not acquired by purchase in Vermont or is received for an amount that does not represent actual value, or if no tax form is filed or it appears to the Commissioner that a tax form contains fraudulent or incorrect information, the Commissioner may, in his or her discretion, fix the taxable cost of the motor vehicle at the clean trade-in value of vehicles of the same make, type, model, and year of manufacture as designated by the manufacturer, as shown in the NADA Official Used Car Guide (New England Edition) or any comparable publication, less the lease end value of any leased vehicle. The Commissioner may compute and assess the tax due thereon, and notify the purchaser thereof forthwith by certified mail, and the purchaser shall remit the same within 15 days thereafter.