William Zac

Duffy

Shareholder
500 N. Akard Street, Suite 4000
Dallas, TX 75201

Overview

Zac focuses his practice on intellectual property and technology law, drawing on hands-on industry experience with software development and implementation projects. Before entering practice, he earned his undergraduate degree in Management Information Systems from the University of Oklahoma and spent several years as a technical resource at a software company serving banks and other financial institutions. That background allows him to provide valuable counsel on matters that involve some form of technology.

Companies facing intellectual property disputes turn to Zac for representation in matters involving copyrights, trademarks, trade secrets, and patents. He also regularly counsels clients on software transactions, including software as a service (SaaS) agreements and contracts to develop or host applications for third parties. When those relationships break down, he litigates them, representing parties in disputes over unpaid service fees and contested software deliverables.

Zac represents companies in trademark litigation involving alleged Lanham Act violations and related unfair competition and false advertising claims. He has prosecuted a substantial volume of trademark applications before the United States Patent and Trademark Office (USPTO) and has represented clients in opposition proceedings before the Trademark Trial and Appeal Board (TTAB). Zac also serves as a World Intellectual Property Organization (WIPO) Arbitrator under the Uniform Domain-Name Dispute Resolution Policy (UDRP) and sits on the WIPO Arbitration and Mediation Center’s panel of mediators.

On data privacy and cybersecurity matters, Zac advises clients across the full life cycle of a data issue. He counsels companies on privacy and cybersecurity compliance, including drafting and updating privacy policies and related practices to satisfy U.S. federal and state law and the EU General Data Protection Regulation (GDPR). He guides clients through the response to data breach incidents, and he defends companies in regulatory actions brought by the Federal Trade Commission for alleged violations of data privacy laws and regulations.

Education

Admissions

Achievements

  • Thomson Reuters – Texas Rising Stars (2011-2018)
  • Woodward/White, Inc. – Best Lawyers in America, Litigation – Intellectual Property (2025-2027); Best Lawyers in America, Litigation – Patent (2027)
  • Memberships

    World Intellectual Property Organization (UDRP Arbitrator, 2026-present; Panel of Mediators, 2026-present)

Overview

Zac focuses his practice on intellectual property and technology law, drawing on hands-on industry experience with software development and implementation projects. Before entering practice, he earned his undergraduate degree in Management Information Systems from the University of Oklahoma and spent several years as a technical resource at a software company serving banks and other financial institutions. That background allows him to provide valuable counsel on matters that involve some form of technology.

Companies facing intellectual property disputes turn to Zac for representation in matters involving copyrights, trademarks, trade secrets, and patents. He also regularly counsels clients on software transactions, including software as a service (SaaS) agreements and contracts to develop or host applications for third parties. When those relationships break down, he litigates them, representing parties in disputes over unpaid service fees and contested software deliverables.

Zac represents companies in trademark litigation involving alleged Lanham Act violations and related unfair competition and false advertising claims. He has prosecuted a substantial volume of trademark applications before the United States Patent and Trademark Office (USPTO) and has represented clients in opposition proceedings before the Trademark Trial and Appeal Board (TTAB). Zac also serves as a World Intellectual Property Organization (WIPO) Arbitrator under the Uniform Domain-Name Dispute Resolution Policy (UDRP) and sits on the WIPO Arbitration and Mediation Center’s panel of mediators.

On data privacy and cybersecurity matters, Zac advises clients across the full life cycle of a data issue. He counsels companies on privacy and cybersecurity compliance, including drafting and updating privacy policies and related practices to satisfy U.S. federal and state law and the EU General Data Protection Regulation (GDPR). He guides clients through the response to data breach incidents, and he defends companies in regulatory actions brought by the Federal Trade Commission for alleged violations of data privacy laws and regulations.

Experience

  • Copyright, Patent + Trademarks

    Represented Seasons USA, a leading manufacturer of novelty holiday-related toys, costumes and decorations, in a series of copyright, patent and trademark

    [more]
  • Trademarks (Trademark Trial and Appeals Board)

    Represented a software services company in trademark opposition proceeding.

  • Software

    Represented a software development company in litigation over unpaid fees allegedly due to faulty or defective software deliverables.

[more]