Md. Code, Public Utilities § 7–515

An electricity supplier that also provides distribution service, or that has an affiliate that provides distribution service, in Pennsylvania, Delaware, West Virginia, Virginia, or the District of Columbia may not provide retail electricity supply service, directly, indirectly, or through an aggregator, marketer, or broker, in the distribution territory of an unaffiliated electric company unless there is electricity supply competition in at least a portion of the distribution service area of the electricity supplier or affiliate.