Sigmund S. "Sig" Wissner-Gross

Sigmund S. "Sig" Wissner-Gross

Brown Rudnick LLP

Recognized since 2010

New York, New York

Practice Areas

Bankruptcy and Creditor Debtor Rights / Insolvency and Reorganization Law

Commercial Litigation

Litigation - Antitrust

Litigation - Bankruptcy

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Sig Wissner-Gross represents a wide variety of clients in complex business litigations. While Sig is resident in Brown Rudnick’s New York office, he has handled cases in over fifteen different jurisdictions around the country.

Sig frequently serves as lead litigation counsel on behalf of creditors in high profile cases, many of them in the Delaware Courts. In recent years, he has successfully prosecuted as lead trial counsel four major cases in Delaware Chancery Court, obtaining summary judgment for his client (Indenture Trustees acting at the direction of bondholders) in two of them, and settling the third case for nearly $2 billion, and in January 2012, obtained a TRO blocking a multi-billion proposed restructuring of the Atlantis Bahamas. He currently serves as lead litigation counsel on behalf of the Lyondell Litigation Trust, in what may be the largest fraudulent transfer litigation ever prosecuted.

Sig also regularly serves as counsel in the prosecution of other high profile and fast moving litigations. He recently negotiated on behalf of a client the settlement of claims exceeding $123 million asserted against the world’s largest food servicing business in a closely followed RICO case filed in the Southern District of New York arising out of an alleged bid-rigging scheme at the United Nations. Many of Sig’s cases involve complex multi-party discovery, in which Sig has supervised a team of attorneys and depositions across the country have been taken. He has been lead counsel in numerous major cases asserting claims for professional liability against financial institutions, auditors and other professionals. He also has successfully represented private and public companies (along with their officers and directors) in the biotech, pharma, telecommunications, and media & entertainment industries, as well as prominent individuals, brokerage firms and other clients.

In addition to his litigation expertise, Sig is often asked by corporate clients to conduct internal investigations and to provide pre-litigation advice. He also has substantial arbitration experience and has handled major arbitrations before the CPR, AAA, and the NASD and NYSE Departments of Arbitration.


  • Seven Times Square
    New York, NY 10036

Bar Admissions

  • New York State Bar Association


  • New York City Bar Association - Member
  • New York State Bar Association - Member

Brown Rudnick LLP
Headquarters: Irvine, California

38 The Best Lawyers in America® awards

14 Best Lawyers: Ones to Watch in America awards

Best Law Firms Badge Full Firm Profile

Recognized in The Best Lawyers in America® 2022 for work in:

  • Bankruptcy and Creditor Debtor Rights / Insolvency and Reorganization Law
  • Litigation - Bankruptcy
  • Commercial Litigation
  • Litigation - Antitrust

Special Focus

  • COVID-19


  • Recognized by Woodward/White Inc.'s The Best Lawyers in America in six separate areas: Bankruptcy and Creditor-Debtor Rights Law/Insolvency and Reorganization Law, Securities Litigation, Commercial Litigation, Antitrust Litigation, Bankruptcy Litigatio


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