William Zeitler represents clients in litigation and provides legal advice in all types of international trade and business transactions disputes. He has concentrated his practice in certain areas of import relief, including Section 337 intellectual property rights litigation before the U. S. International Trade Commission primarily involving patent, trademark, trade secret, gray market, copyright and unfair competition cases, as well as antidumping and countervailing duty investigations and administrative reviews before the U. S. Department of Commerce and the U.S. International Trade Commission.

He has also concentrated his practice in the area of economic sanctions where he represents clients before the Office of Foreign Assets Control and, in the area of export controls, where he represents clients before the U. S. Department of State, particularly in matters involving ITAR and export compliance.

William Zeitler also represents clients in litigation before U. S. courts in international transactions, involving matters relating to licensing, breach of contract, and fraud.