Is sentry insurance a mutual company? Sentry Insurance A Mutual Company operates as a mutual insurance company in the United States. It offers auto, motorcycle, equipment physical damage, and life and annuities insurance products to inpiduals and families; and employee benefits and business life insurance products.Where is sentry insurance located? Sentry Insurance - Corporate Headquarters is a business providing services in the field of Insurance - Agents & Brokers. The business is located in Stevens Point, Wisconsin, United States.What is sentry service? Messer Sentry Service is designed to cover all Messer machines with a thorough maintenance check. Signing up for Messer Sentry Service is the first step to keeping your maintenance program on track.