A stable sorting system and method for use with a sort accelerator having a rebound sorter as a merger is disclosed. The stable sorting system maintains an output order of records which have equal keys. This output order is the same order of those records as they entered the rebound sorter. Stable sorting is maintained in both the sorting and the merging operations of the sort accelerator. An additional byte is inserted between the key and the data of a record to preserve record order for records having equal keys.