The Casualty Actuarial Society (CAS) is a professional society of actuaries specializing in property and casualty insurance. The two levels of CAS membership are Associate (ACAS) and Fellow (FCAS). Requirements for these levels of membership include a comprehensive series of exams. Topics covered in the exams include statistics, mathematics, finance, economics, insurance, enterprise risk management, and actuarial science. Another class of CAS membership, Affiliate, includes qualified actuaries who practice in property-casualty insurance but do not meet the qualifications to become an Associate or Fellow.