There are many reasons why developing a keen understanding of medical claims seasonality is becoming an increasingly critical component of health insurer financial management. Such reasons include: increased issuance of products having relatively steep seasonality patterns; reduced claim processing lag times leading to an increase in the proportion of claim liabilities associated with very immature incurral months; and greater emphasis by insurer senior management in forecasting and monitoring monthly financial results. In this session, speakers will discuss a wide variety of issues surrounding the topic of developing and using claims seasonality models, with a particular focus on implications for valuation and forecasting functions.