In the third year of study professionals make up most of the teaching body. Professional seminars are held throughout the year to complement theoretical classes. The following majors are offered : QUANTITATIVE MARKETING, RISK MANAGEMENT and FINANCIAL  ENGINEERING, HEALTH ECONOMETRICS, STATISTICS AND COMPUTER SCIENCE, BIO-STATISTICS and STATISTICAL TOOLS FOR INDUSTRIAL APPLICATIONS. These majors allow students to specialise in one area of advanced applications in statistics. In the third year, students add a new professional dimension to their scientific studies during a six month End of Study Internship. The students are placed in the statistics, computer science or economics departments of either public or private companies in France or abroad.

The following are some examples of internship themes : the elaboration of a fragile scoring chain, modelling the correlation between credit risk and market risk, web mining and measuring the audience on the internet through the use of artificial intelligence tools in auditing, the study of mixed models to coefficients of random heteroscedastic regression in quantitative genetics.

Thanks to a partnership agreement with the University of Rennes 1, ENSAI students, who wish to pursue a PhD, may follow a specially organised programme. In order to carry out their research the students are placed within laboratories such as INSERM, CNRS, CREST and INRA working for clients such as RENAULT, EUROCOPTER, SNCF, GLAXOSMITHKLINE.