Maryland Code, Insurance § 11-205

(1) past and prospective loss experience within and outside the State;

(2) conflagration and catastrophe hazards, if any;

(3) past and prospective expenses, both countrywide and those specially applicable to the State;

(4) underwriting profits;

(5) contingencies;

(6) investment income from unearned premium reserve and reserve for losses;

(7) dividends, savings, or unabsorbed premium deposits allowed or returned by insurers to policyholders; and

(8) all other relevant factors within and outside the State.

(f)(1) Risks may be grouped by classifications for the establishment of rates and minimum premiums.

(2) Classification rates may be modified to produce rates for individual risks in accordance with rating plans that establish standards for measuring variations in hazards or expense provisions, or both.

(3) The standards may measure any difference among risks that are demonstrated objectively to the Commissioner to have had a direct and substantial effect on losses or expenses.

(4) Notwithstanding any other provision of this subsection, a rate may not be based wholly or partly on geographic area itself, as opposed to underlying risk considerations, even though expressed in geographic terms.