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Gregory K. Arenson


Mr. Arenson is a seasoned business litigator with experience representing clients in a variety of areas, including antitrust, securities, and employee termination. His economics background has provided a foundation for his recognized expertise in handling complex economic issues in antitrust cases, both as to class certification and on the merits. He argued the appeals in In re High Fructose Corn Syrup Antitrust Litig., 295 F.3d 651 (7th Cir. 2002), and In re Hydrogen Peroxide Antitrust Litig., 552 F.3d 305 (3d Cir. 2009).

Mr. Arenson has been active in the New York State Bar Association. He was a member of the House of Delegates from 2013 to 2017. He was Chair of the Commercial and Federal Litigation Section from June 2013 through May 2014. He has been Co-Chair of the New York State Bar Association Task Force on the State of Our Courthouses and a member of the New York State Bar Association Special Committee on Discovery and Case Management in Federal Litigation.


Mr. Arenson has been a partner in the firm since 1993. Prior to joining Kaplan Fox, Mr. Arenson was a partner with Proskauer Rose. Earlier in his career, he was a partner with Schwartz Klink & Schreiber, and an associate with Rudnick & Wolfe (now DLA Piper).

Mr. Arenson writes frequently on discovery issues and the use of experts. His published articles include: "Rule 68 Offers of Judgment and Mootness, Especially for Collective or Class Actions," 20 NY LITIGATOR 25 (2015); "Report on Proposed Amendments to Federal Rule of Civil Procedure 45," 17 NY LITIGATOR 21 (2012); “Rule 8 (a)(2) After Twombly: Has There Been a Plausible Change?” 14 NY LITIGATOR 23 (2009); “Report on Proposed Federal Rule of Evidence 502,” 12 NY LITIGATOR 49 (2007); “Report: Treating the Federal Government Like Any Other Person: Toward a Consistent Application of Rule 45,” 12 NY LITIGATOR 35 (2007); “Report of the Commercial and Federal Litigation Section on the Lawsuit Abuse Reduction Act of 2005,” 11 NY LITIGATOR 26 (2006); “Report Seeking To Require Party Witnesses Located Out-Of-State Outside 100 Miles To Appear At Trial Is Not A Compelling Request,” 11 NY LITIGATOR 41 (2006); “Eliminating a Trap for the Unwary: A Proposed Revision of Federal Rule of Civil Procedure 50,” 9 NY LITIGATOR 67 (2004); “Committee Report on Rule 30(b)(6),” 9 NY LITIGATOR 72 (2004); “Who Should Bear the Burden of Producing Electronic Information?” 7 FEDERAL DISCOVERY NEWS, No. 5, at 3 (April 2001); “Work Product vs. Expert Disclosure – No One Wins,” 6 FEDERAL DISCOVERY NEWS, No. 9, at 3 (August 2000); “Practice Tip: Reviewing Deposition Transcripts,” 6 FEDERAL DISCOVERY NEWS, No. 5, at 13 (April 2000); “The Civil Procedure Rules: No More Fishing Expeditions,” 5 FEDERAL DISCOVERY NEWS, No. 9, at 3 (August 1999); “The Good, the Bad and the Unnecessary: Comments on the Proposed Changes to the Federal Civil Discovery Rules,” 4 NY LITIGATOR 30 (1998); and “The Search for Reliable Expertise: Comments on Proposed Amendments to the Federal Rules of Evidence,” 4 NY LITIGATOR 24 (1998). He was co-editor of FEDERAL RULES OF CIVIL PROCEDURE, 1993 AMENDMENTS, A PRACTICAL GUIDE, published by the New York State Bar Association; and a co-author of “Report on the Application of Statutes of Limitation in Federal Litigation,” 53 ALBANY LAW REVIEW 3 (1988).

Mr. Arenson serves as a mediator in the U.S. District Court for the Southern District of New York. In addition, he is an active alumnus of the Massachusetts Institute of Technology, having served as a member of the Corporation, a member of the Corporation Development Committee, vice president of the Association of Alumni/ae, and member of the Annual Fund Board (of which he was a past chair).

S.B., Massachusetts Institute of Technology (1971)
J.D., University of Chicago (1975)

Bar Affiliations and Court Admissions:
Bar of the State of Illinois (1975)
Bar of the State of New York (1978)
U.S. Supreme Court
U.S. Courts of Appeals for the Second, Third and Seventh Circuits
U.S. District Courts for the Northern and Central Districts of Illinois, and the Southern, Eastern Districts of New York, and the Eastern District of Michigan
U.S. Tax Court

Professional Affiliations:
New York State Bar Association 
Association of the Bar of the City of New York
American Bar Association