Md. Code Ann., Tax-Gen. § 7.5-102 — § 7.5-102

(a) A tax is imposed on annual gross revenues of a person derived from digital advertising services in the State.
(b) (1) For purposes of this title, the part of the annual gross revenues of a person derived from digital advertising services in the State shall be determined using an apportionment fraction:
(i) the numerator of which is the annual gross revenues of a person derived from digital advertising services in the State; and
(ii) the denominator of which is the annual gross revenues of a person derived from digital advertising services in the United States.
(2) The Comptroller shall adopt regulations that determine the state from which revenues from digital advertising services are derived.
(c) A person who derives gross revenues from digital advertising services in the State may not directly pass on the cost of the tax imposed under this section to a customer who purchases the digital advertising services by means of a separate fee, surcharge, or line–item.