The National Labor Relations Board, an independent federal agency that enforces labor laws, issued updated guidance Wednesday stating that college athletes are now considered employees and can therefore unionize. In June, the National Collegiate Athletic Association made a seismic shift by announcing that athletes can earn money through self-promotion, although universities are still prohibited from directly paying them. It followed a Supreme Court ruling that the NCAA should pay athletes for education-related benefits.

The NLRB said players “perform services for institutions in return for compensation and subject to their control” and are therefore employees under the National Labor Relations Act. Any institution that bars athletes from unionizing is violating the law, the memo warns. The NLRB investigates labor law violations and has the power to prosecute employers.