In professional sports, a salary cap (often calle a wage cap in the United Kingdom) is a limit on the amount of money a team can spend on player salaries, either as a per-player limit or a total limit for the team's roster (or both). Several sports leagues have made salary caps mandatory, both as a method of keeping overall costs down, and in order to balance the league so a wealthy team cannot become dominant simply by buying all the top players. Salary caps are often the major issue in negotiations between management and players' unions.