The main factor that sets MLS apart from leagues like the Saudi Pro League and Liga MX is the existence of a salary cap, which players themselves have even criticized. This system often drives top American soccer talent to move abroad in search of higher salaries.

Major League Soccer (MLS) operates under a unique model in world football, functioning as a unified league where teams are not fully independent clubs but rather franchises under a single structure.

This means that player contracts are owned by the league itself, not by individual teams, allowing for strict financial control.

Each team has an annual salary cap, but can sign up to three “Designated Players” (such as Messi or Insigne), who earn above the limit; the excess is paid directly by the club. Additionally, mechanisms like General Allocation Money (GAM) help offset salary cap charges for certain players.

The system also includes regulations on the number of foreign players per team, special player categories (such as young or homegrown players), and a maximum number of players allowed on a roster.

The rules are governed by collective bargaining agreements (CBA) between the league and the players’ union, as well as MLS’s internal regulations. This structure is designed to maintain competitive balance, limit excessive spending, and promote the development of domestic talent, while still allowing space for star signings that elevate the league’s profile.