An accomplished trial lawyer, William Mahoney has brought a pragmatic, value-driven and results-oriented approach to complex business litigation for more than 25 years. Bill represents corporations of all sizes in a broad spectrum of commercial litigation matters, including those related to employment discrimination and sexual harassment, unfair competition and restrictive covenants, theft of trade secrets, class actions, copyright infringement and intellectual property, and professional liability.
Bill has provided management-side counsel in connection with union campaigns and elections, negotiations of collective bargaining agreements, and defending against unfair labor practices charges before the National Labor Relations Board (NLRB). Bill has developed a robust practice in counseling businesses in employee departure litigation, regularly seeking or defending against injunctions in both state and federal court.
Bill also represents financial institutions such as brokerage firms, investment advisers and banks in all manner of disputes, including securities litigation and arbitration, regulatory investigations and enforcement proceedings.
Featured Representative Matters
Represented a futures commission merchant in a state court action by traders seeking over $1 billion in damages relating to trades on the Chicago Mercantile Exchange.
Advised one of the United States’ largest veal and lamb processing companies in back-to-back union organizing campaigns, both of which resulted in the company winning the union election. Successfully represented the same company when the union subsequently filed numerous unfair labor practices charges against the company, including the alleged wrongful termination of a pro-union employee; following a two-week hearing before the NLRB, all but the most trivial charges were dismissed, the employee termination was upheld, and the election results were confirmed.
Represented a brokerage firm in a $25 million auction-rate securities case in federal court, securing a favorable settlement shortly after the jury trial began.
Represented a leading global biotech company in an injunction action against a former high-level employee and the competing firm he joined after it was discovered that the employee had downloaded thousands of the company’s computer files. Successfully obtained an injunction against the former employee and the competitor and subsequently negotiated a resolution under which the competitor terminated its employment relationship with the employee.
Obtained a multimillion-dollar award on behalf of a broker-dealer client against a competing firm for unfair competition.
Secured dismissal of a financial advisory firm’s lawsuit against a distressed debt investment firm, in which the plaintiff asserted claims of tortious interference with contract and unfair competition and sought a seven-figure fee.
Secured a jury verdict in favor of a national entertainment franchise in a premises liability matter, following a week-long trial in federal court.
Defended multiple age and religious discrimination claims by former employees against a brokerage firm both in federal court and arbitration, obtaining an award of attorney fees against the employee in one matter and securing a settlement in which another employee paid a significant amount to the client.
Represented a national bank in a class action arising out of a municipal debt issuance.
Defended a regional broker-dealer against claims brought by a former broker for fraudulent inducement and related torts.
Represented a national computer retailer in a contractual dispute with an internet service provider that was seeking millions of dollars in damages.
Community Impact
When not practicing law, Bill devotes his time to charitable organizations, having served formerly as the president of the board of directors for the Make-A-Wish Foundation of Philadelphia and Southeastern Pennsylvania. He was previously president of the board of managers for the Abington YMCA and was named its Volunteer of the Year in 2014. He received the award as a “Y Champion for Social Responsibility” based on his leadership of the Abington YMCA annual giving campaign, among other contributions.
