Exhibit 21.1 Subsidiaries of the Registrant The following companies are subsidiaries of the Registrant as of December 31, 1999. Jurisdiction of Percentage Name Incorporation Ownership - ---- --------------- ---------- RLI Insurance Company Illinois 100% RLI Aviation, Inc. Illinois 100% Replacement Lens Inc. Illinois 100% Mt. Hawley Insurance Company Illinois 100% RLI Insurance Ltd. Bermuda 100% RLI Insurance Agency Ltd. Canada 100% RLI Mortgage Services, LLC Illinois 50% RLI Premium Finance, LLC Georgia 55% UIH, Inc. Illinois 100% Underwriters Indemnity Company Texas 100% Underwriters Settlement Services, Inc. Texas 100% Planet Indemnity Company Illinois 100% Underwriters Indemnity General Agency, Inc. Texas 100% 36