Opportunities for students to share their thinking with the class--which I refer to as "work-sharing practices--require a profound shift in who is positioned with intellectual authority in mathematics classrooms. This study explores work-sharing practices in one sixth grade mathematics classroom through an interactional lens. Video analysis revealed three types of work-sharing interactions along a continuum of distributions of intellectual authority, ranging from the presenting student holding authority to the teacher holding authority. Notably, in the center of the continuum were instances in which the student was initially positioned with authority, but that authority shifted to the teacher in the next moment, largely based on correctness of the student's work. Findings suggest the need to deepen our understanding of authority dynamics in work-sharing interactions, as the field works to center students' thinking. [For the complete proceedings, see ED657822.]