In a major ruling on Proposition 64, a Los Angeles appellate court has made it far more difficult for false advertising class actions to be filed under the state’s unfair competition law.

In a 21-page ruling released late Tuesday, the 2nd District Court of Appeal held that under Prop 64 — the 2004 ballot measure that restricted private attorney general suits — the “mere likelihood” of injury is no longer enough to have standing to file a class action under the UCL’s fraudulent acts provision.