Why do employees in a post-Fordist organization work more hours than they initially prefer? While the relationship between ‘new’ labor conditions and a gap between actual and preferred working hours has been established, a precise explanation falls short. Shortly after the turn of the century, the extensive Dutch Time Competition research project suggested that competition between employees is the driving mechanism. This suggestion was not tested at the time, leaving an unsatisfactory open end. Recent literature proposes an alternative mechanism for explaining time-greediness: goal orientation driven by team production. This joint production motivation does not fit with the competition mechanisms which are driven by individual incentives. Data of the Time Competition project, with information on 1114 employees from 30 organizations, offer an until now unused opportunity to test both explanations. Using mediation analysis, the time competition mechanism will have to prove itself against the null hypothesis, stating the theory based on joint production motivation. The latter emerges as the clear winner .