Md. Code, Tax - Property § 8–204

(a) Personal property subject to assessment shall be assessed annually.

(b) The assessment of personal property for the date of finality is based on:

(1) information required to be included in the report to be filed under § 11-101 of this article by April 15 following the date of finality; or

(2) if a report is not filed or is incomplete, any available information that the Department has.