In North America, sports organizations are organized in a closed system of competition. In contrast to the European Sports Model's pyramid structure and relegation system, the main sports leagues in the United States are largely closed and autonomous, with an average of 30–32 clubs. A few games may be played against other teams within their division (e.g., the MLS Cup), but most U.S. sports leagues do not have any direct rivals for membership. The primary exception is the National Football League (NFL), which has had several rivalries over the years with various members of the American Athletic Conference. Other major sports leagues that have open systems include the NBA and MLB. However, even in these cases, there are strong incentives for teams to compete against others in their division or conference, since this improves their chances of making the post-season play-offs. U.S. sports leagues are generally owned by investors who seek to maximize profits by organizing competitive seasons and tournaments. The only major professional sports league that is publicly funded is the NFL, which receives $7 billion per year from the federal government to help cover the costs of running its league office and providing financial assistance to support operating budgets for its teams. The majority of U.S. sports franchises are owned by individuals or businesses that purchase them en masse from previous owners or from the league itself.