​​Surplus lines insurers specialize in property or liability insurance in instances where it is unavailable from insurers licensed in the state. An insurer domiciled in a United States Jurisdiction that seeks approval as a surplus lines insurer must apply annually with the Maryland Insurance Administration to retain its authority. A list of eligible insurers may be found through the Company Search function.

Under the Dodd-Frank Wall Street Reform and Consumer Protection Act, a surplus lines broker may place non-admitted insurance with, or procur non-admitted insurance from, a non-admitted insurer domiciled outside the United States (alien insurer) provided that the insurer is listed on the Quarterly Listing of alien insurers maintained by the International Insurers Department of the National Association of Insurance Commissioners (NAIC). Select the alphabetical listing on the NAIC website https://i-site.naic.org/cgi-bin/statenet/publications_alpha_listing.htm then select Quarterly Listing of Alien Insurers to retrieve the most recent list.