CGC grading is located in Sarasota, Florida. United States address: Certified Guaranty Company, LLC P.O. Box 4738 Sarasota, FL 34230 United States Additionally, NGC International UK Limited (NGC UK) is the UK affiliate of Certified Guaranty Company (CGC) in Europe. United Kingdom address: NGC International UK Ltd. 69 Southampton Row, Third Floor Bloomsbury WC1B 4ET London, United Kingdom