Exhibit (21) LIST OF SUBSIDIARIES OF HSB GROUP, INC. NAME OF COMPANY STATE/JURISDICTION OF INCORPORATION/ FORMATION The Allen Insurance Company Bermuda The Boiler Inspection and Insurance Company of Canada (wholly-owned by HSB Engineering Insurance Ltd.) Canada Cordova/HSB Ventures, LLC (50% owned by HSB Ventures, Inc.) Georgia EIG, Co. (wholly owned by The Hartford Steam Boiler Inspection and Insurance Company) Delaware Hartford Steam Boiler Colombia Ldta. (90% owned by The Hartford Steam Boiler Inspection and Insurance Company and 10% by HSB Group, Inc.) Colombia The Hartford Steam Boiler Inspection and Insurance Company Connecticut The Hartford Steam Boiler Inspection and Insurance Company of Connecticut Connecticut The Hartford Steam Boiler Inspection and Insurance Company of Texas Texas Hartford Steam Boiler International GmbH (wholly-owned by The Hartford Steam Boiler Inspection and Insurance Company) Germany Hartford Steam Boiler (M) Sdn. Bhd. (wholly-owned by The Hartford Steam Boiler Inspection and Insurance Company) Malaysia Hartford Steam Boiler (Singapore) PTE Ltd. (wholly-owned by The Hartford Steam Boiler Inspection and Insurance Company) Singapore HSB Africa (wholly-owned by HSB Engineering Insurance Limited) South Africa HSB Associates, Inc. New York HSB Capital I Delaware HSB Capital II Delaware HSB Capital Corp. I, Inc. (wholly-owned by HSB Engineering Finance Corporation) Delaware HSB Engineering Finance Corporation Delaware HSB Engineering Insurance Limited (wholly-owned by EIG Co.) England HSB Haughton Engineering Insurance Services, Ltd. (wholly-owned by HSB Engineering Insurance Limited) England HSB Haughton (Ireland) Limited (wholly-owned by HSB Haughton Engineering Services, Ltd.) Ireland HSB Inspection Quality Limited (wholly-owned by HSB Haughton Engineering Insurance Services, Ltd.) England HSB Investment Corporation (wholly-owned by The Hartford Steam Boiler Inspection and Insurance Company) Connecticut HSB Professional Loss Control, Inc. (wholly-owned by The Hartford Steam Boiler Inspection and Insurance Company) Tennessee HSB Reliability Technologies Corp. (wholly-owned by The Hartford Steam Boiler Inspection and Insurance Company) Florida HSB-RS Korea (wholly-owned by The Hartford Steam Boiler Inspection and Insurance Company) Korea HSB Servicetouch, LLC (52% owned by The Hartford Steam Boiler Inspection and Insurance Company) Connecticut HSB Ventures, Inc. (wholly-owned by HSB Engineering Finance Corporation) Delaware Integrated Process Technologies, LLC (51% owned by The Hartford Steam Boiler Inspection and Insurance Company) Delaware One State Street Intermediaries Connecticut Ra-Hart Investment Company (wholly-owned by The Hartford Steam Boiler Inspection and Insurance Company) Texas Solomon Associates, Inc. Texas Solomon Associates International, Inc. (wholly-owned by Solomon Associates, Inc.) Texas Solomon Associates Limited (wholly-owned by Solomon Associates International, Inc.) United Kingdom Structural Integrity Associates, Inc. (wholly-owned by The Hartford Steam Boiler Inspection and Insurance Company) California