Abstract
This paper analyzes spillover effects in sports leagues that are embedded in a system of promotion and relegation. Based on a contest model of a professional sports league with a top division and a second division, we show that league prizes and club efficiencies have opposing effects; while a stronger second division that offers a higher league prize leads to a more balanced top division, the opposite is true for a stronger second division whose clubs become more cost efficient. Moreover, we demonstrate that a higher second-division prize induces a lower investment level, but higher profits in the top division, while higher club efficiency in the second division leads to both a lower investment level and lower profits in the top division. These results have important policy implications for the organization of sports leagues