A stream management system may implement dynamic management of a data stream. Utilization data of different partitions of a data stream may be tracked. When routing a data record received at the stream management system, a partition may be dynamically identified for the data recorded. The data record may then be directed to the identified partition. Other management operations, such as repartitioning the data stream or reassigning resources for processing data records in the data stream may be performed based on the utilization data tracked for the partitions.