Maryland Code, Tax-Property § 8-416

(a) Assessments of personal property for a taxable year are based on information as of the preceding date of finality and are final as of the date of the notice unless appealed under § 8-411 of this subtitle.

(b) Except for real property that subsequently becomes assessable for the semiannual date of finality or quarterly date of finality, real property assessments are final as of the date of finality.