A recent bombshell lawsuit by The Home Depot alleges patterns of antitrust violations, illegal collusion, and anti-competitive conduct by the Visa and MasterCard credit card networks. The suit arises in a climate in which the networks are increasingly under attack by retailers, and in which The Home Depot is embroiled in extensive litigation stemming from a massive 2014 breach of customer data. Finally, for consumers concerned with payment card security, the suit highlights potential weaknesses in some U.S. payment card technologies – particularly when compared to systems widely used overseas.