This Practice note gives an overview of class (or collective) action arbitration in the United States of America (USA or US) and its evolution, focussing on the Green Tree Financial v Bazzle decision and its impact. The Note also details the AAA and JAMS Rules for class arbitration along with post— Bazzel developments in the US Supreme Court. The Practice Note also considers the enforceability of class-action waivers, including in relation to employment contracts.