In a 5-4 decision, U.S. Supreme Court said AT&T Mobility could enforce a contract that required cellphone customers to arbitrate disputes individually and waive the right to bring claims as a class. The decision could have broad implications for disputes involving not just consumers, but employees who sign arbitration agreements.

“It should have the effect of reducing certain types of class actions, those [involving plaintiffs] with a contract,” said Alan Kaplinsky of Ballard Spahr, a lawyer who has long advised clients on consumer arbitration agreements with class action waivers.