Zack represents multinational private and public companies, financial institutions, boards of directors and individuals in a broad range of high-stakes and complex internal and government investigations. He has advised clients on investigations involving allegations of insider trading, securities fraud, money laundering, antitrust violations, recordkeeping violations, whistleblower retaliation and other areas of financial crime or fraud. Zack also routinely advises on corporate governance and compliance matters, including with respect to data privacy issues.

Zack has represented clients in connection with criminal and civil investigations by the Department of Justice, Securities and Exchange Commission, Federal Trade Commission, state attorneys general and others.

His representations have spanned a variety of industries, with a particular focus on technology and media, financial services, telecommunications and pharmaceuticals.