The Foundation of All Great Collections. Professional Sports Authenticator (PSA) is the largest and most trusted third-party trading card authentication and grading company in the world. Since its inception in 1991, PSA has certified over 40 million cards and collectibles with a cumulative declared value of over a billion dollars. As the only third-party grading service to offer a guarantee on its services, PSA has emerged as the clear leader in authentication and grading for trading cards and other collectibles.