Tort Litigation, Securities Fraud, Whistleblower Claims, and Class Actions. Mason LLP is a premier law firm based in Washington, D.C. with a proven track record of success in leveling the playing field for their clients. With over 30 years of experience, the team at Mason LLP has recovered more than $1 billion for their clients in a variety of practice areas including data breach, mass tort litigation, securities fraud, whistleblower claims, and class actions. Trust in Mason LLP to provide expert legal representation and fight tirelessly for justice on behalf of their clients. Contact Mason LLP today to schedule a consultation and learn how they can help you with your legal needs.