Sean C. Keenan, Ph.D., is currently a vice president in Citigroup's Risk Architecture Group, where he is involved in the development of quantitative tools and methodologies for assessing credit risk for obligors and pools of obligors, as well as for a variety of credit and structured credit portfolios. His research involves a wide range of Monte Carlo applications, often with large data sets, and SAS is his preferred tool for handling these tasks. Sean holds a Ph.D. in Economics from New York University.