ZwillGen Appoints Two New Shareholders and Adds Two New Attorneys

NEW YORK, SAN FRANCISCO, and WASHINGTON, DCZwillGen is pleased to announce that two veteran attorneys of its California and New York offices have been newly appointed Shareholders of the Firm. In addition, ZwillGen has added one new attorney in Washington, DC to support its growing International Law Enforcement practice and one new attorney in New York to bolster its privacy capabilities, including privacy due diligence for acquisitions, mergers, and investment transactions.

Anna Hsia has been voted in as a Partner of ZwillGen Law LLP in San Francisco and Mason Weisz has been voted in as a Shareholder in ZwillGen PLLC’s New York office.

“Anna and Mason have become invaluable parts of the Firm and we will be looking to them as leaders to further develop our capabilities on both coasts outside of the Washington, DC office,” said Marc Zwillinger, ZwillGen’s Founder and Managing Member.

Additionally, Liz DeYoung, a former federal prosecutor at the Department of Justice, Criminal Division, Office of International Affairs, has been brought on in Washington, DC to assist the Firm’s growing Law Enforcement practice, especially with regard to working with International Law Enforcement and Cloud Act requests. Also, former Cleary Gottlieb Steen & Hamilton LLP attorney Jane Rosen has joined the Firm’s New York office to assist on privacy-related matters, including evaluating privacy due diligence as it relates to a wide spectrum of transactions ranging from acquisitions to investments.

About the Attorneys

Anna Hsia – Anna counsels clients on product development and privacy issues, and litigates complex business disputes. Her broad clientele includes Bay Area companies in the gig economy, online gaming, cloud computing, advertising, and biotechnology space. Anna has also served as the head of the Firm’s West Coast operations.
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Mason Weisz – Mason focuses on a wide variety of privacy, security, and Internet issues, with emphasis on helping companies that are subject to both US and European law, including in relation to the California Consumer Privacy Act and EU General Data Protection Regulation. For the past several years, he has led ZwillGen’s international efforts. A former web designer, he has extensive experience with the technology that drives digital media and e-commerce.
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Liz DeYoung – Liz has more than a decade of combined experience in private and government practice. Liz advises clients regarding demands for user data under ECPA, the CLOUD Act and data localization issues, engagement with law enforcement authorities (both within and outside of the United States), and other matters concerning cross-border access to data. She also provides a range of corporate governance, transactional, and commercial contracting advice to clients.
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Jane Rosen – Jane’s practice focuses on privacy, data protection, and technology-related issues. As a Certified Information Privacy Professional (CIPP/US), she advises clients on their legal obligations under applicable privacy laws and regulations, as well as strategies for managing compliance and risks. She has a strong background in transactional contexts such as mergers and acquisitions, joint ventures, financings, restructurings, capital markets offerings and various commercial, licensing, and services arrangements.
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About ZwillGen

ZwillGen has built a strong practice counseling the nation’s leading technology and media companies and handling their highest profile online legal issues.

Following years of running practice groups at the nation’s largest law firms, ZwillGen was founded on the principle of delivering thoughtful and practical solutions more efficiently. Today, ZwillGen offers unique services from a team of highly specialized attorneys, some of whom have spent the last 20 years developing their knowledge and experience with leading clients, firms, and issues. In addition, ZwillGen makes legal advice more accessible to its clients by offering alternatives to the traditional hourly law firm model including innovative approaches that directly align firm incentives with client success.


The firm represents prominent Internet companies, media companies, Internet service providers, app developers, social networking sites, sharing economy companies, wireless carriers, video game publishers, fantasy sports providers, Internet and computer security firms, hedge funds, and a variety of traditional brick and mortar businesses in connection with their online practices.