The analysis of time series is a central issue in economic research and many other scientific applications. However, the data management functionality for this field is not provided by general-purpose DBMSs. Therefore, we propose a data model of a specialized Time Series Management System (TSMS) which accounts for these needs. The model is centered around an object-oriented kernel that offers the classes and value types needed for the target applications. The model provides base classes for multivariate time series and for groups as a means to hierarchically partition the time series space. The system offers a computationally complete data manipulation language including capabilities to query time series and groups. An elaborate array model is supported to account for the functional needs of statistical computations. Furthermore, a customizable calendar system providing a variety of predefined calendars is included.