Michael Rosenwasser

David Gringer is a nationally recognized trial lawyer with a distinguished record of success in antitrust, false advertising, and complex civil litigation. Mr. Gringer is known for his unique and powerful combination of aggressive advocacy, deep substantive knowledge, and strategic judgment. Clients and market commentators describe David to Chambers USA as “a go-to antitrust lawyer for difficult cases,” “a really strategic thinker,” and someone who “doesn’t...

David Nissenbaum is a lawyer recognized by Best Lawyers in the practice area of Private Funds / Hedge Funds Law. David practices law in New York, New York Best Lawyers has recognized David Nissenbaum since 2023. The Best Lawyers recognition is based on a peer-review survey of lawyers in the same geographic region and legal practice area. The recognition reflects the professional regard in which David Nissenbaum is held by other lawyers.

Robert E. Helpern is a founding partner of the firm's Real Estate practice. For more than thirty years, Bob has leveraged his legal experience to identify key issues and craft creative solutions for clients including real estate funds, banks, developers, owners of commercial and multi-family properties, and tenants. Bob has been involved in acquisitions and sales, leasing, joint ventures, mortgage and mezzanine financing, and restructuring of debt. Representative clients include one of the la...

Andrea Vacca has practiced family law in New York since 1993 and has spent more than two decades focused exclusively on non-adversarial resolution: collaborative divorce , divorce mediation , and prenuptial agreements . She founded Vacca Family Law Group on the conviction that court is rarely necessary and almost always costly, in money, privacy, and family relationships. Andrea is a past president of the New York Association of Collaborative Professionals , a member of the International Acad...

Jessica L. Toelstedt joined Mason Law & Mediation LLC as a partner in 2025 and has practiced family and matrimonial law in New York for nearly twenty years. Before joining the firm, she was a partner at Berkman Bottger Newman & Schein, LLP, where she served as Co-Chair of the Mediation and Collaborative Law Practice. Jessica represents clients in matters involving Family Law, Collaborative Law: Family Law, and Family Law Mediation . After spending the first half of her career litigati...

Robert Gunther has over 35 years of experience as a trial lawyer representing life sciences, pharmaceutical and technology clients in intellectual property and technology litigation at both the trial and appellate levels. Mr. Gunther is a Fellow of the American College of Trial Lawyers, and he has consistently been selected by Chambers USA , Managing IP magazine, LMG Life Sciences and IAM as a leading lawyer in the area of patent litigation.

Helene M. Freeman is a partner in the Litigation Department at Phillips Nizer LLP. Ms. Freeman's practice is focused on all facets of entertainment, publishing, the arts and fashion. She has counseled multinational record distributors, leading musical performing groups, film and television producers and distributors, international music publishing companies, theatrical producers, authors and advertising agencies. As a litigator with more than 30 years' experience, Ms. Freeman has been trial a...

Jason B. Klimpl is a partner in the firm's Employment, Staffing Law, and Corporate practice groups and General Counsel to the New York Staffing Association. Jason advises clients on a broad range of employment matters, such as: wage and hour compliance , including issues relating to overtime and exemptions from overtime, the minimum wage, tips, the payment of and deductions from wages, governmental wage and hour audits, recordkeeping obligations, and federal and state labor laws; equal opport...

Louis Ederer is a lawyer recognized by Best Lawyers in the practice area of Litigation - Intellectual Property. Louis practices law in New York, New York Best Lawyers has recognized Louis Ederer since 2026. The Best Lawyers recognition is based on a peer-review survey of lawyers in the same geographic region and legal practice area. The recognition reflects the professional regard in which Louis Ederer is held by other lawyers.

Tara B. Mulrooney is a lawyer recognized by Best Lawyers in the practice areas of Construction Law and Litigation - Construction. Tara B. practices law in New York, New York Best Lawyers has recognized Tara B. Mulrooney since 2026. The Best Lawyers recognition is based on a peer-review survey of lawyers in the same geographic region and legal practice area. The recognition reflects the professional regard in which Tara B. Mulrooney is held by other lawyers.