To determine which law firms represent America’s largest corporations, we searched public records to find outside counsel used by the Fortune 100 for corp­orate, contracts litigation, labor litigation, torts litigation and intellectual property.

For corporate work, we searched company and law firm press releases gathered by ALM Legal Intelligence, as well as mergers and acquisition data compiled by Thomson Reuters for The American Lawyer‘s Corporate Scorecard. For the litigation areas, we searched PACER, which provides public access to electronic court records from federal appellate and district courts.