Kirby McInerney LLP | Financial Litigation Law Firm | Karen Lerner
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Karen  M. Lerner


Healthcare Fraud


  • The University at  Albany, SUNY (B.A. summa cum laude, Phi Beta Kappa, 1988)
  • University of Pennsylvania School of Law (J.D. 1991)


  • United States Supreme Court
  • U.S. Court of Appeals for the 2nd and 3rd Circuits
  • U.S. Court of Appeals for the District of Columbia
  • U.S. District Court for the Southern and Eastern Districts of New York
  • U.S. District Court for the District of New Jersey
  • New York State Bar
  • New Jersey State Bar
  • District of Columbia Bar
Karen M. Lerner
Tel: 212.371.6600
Fax: 212.751.2540
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Karen M. Lerner is a partner in our New York office focused on antitrust and commodities litigation. 

Over the course of her career, Ms. Lerner has successfully litigated complex class actions that have recovered billions of dollars on behalf of institutional and individual plaintiffs. She has played important roles in several landmark antitrust cases and remains one of the few women ever appointed as Interim Co-Lead Class Counsel in a Commodity Exchange Act case.  In addition to her litigation work, she also advises individuals, corporations and non-profits regarding business practices and corporate governance.  In 2022, Ms. Lerner was named a Fellow of the American Bar Foundation, a global honorary society limited to one percent of lawyers licensed to practice in each jurisdiction.

Some of her recent antitrust and Commodities Exchange Act work includes:
  • Co-lead counsel in In re Credit Default Swaps Auctions Litigation, a class action brought by the firm and the Office of the Attorney General for the State of New Mexico alleging antitrust violations and market manipulation in the credit default swaps market.  The case is ongoing. 
  • Court appointed Executive committee member and class counsel in In re Digital Advertising Antitrust Litigation, representing publishers alleging that Google monopolized and suppressed competition in online display advertising.
  • Representation of the exchange-based class in In re LIBOR-Based Financial Instruments Antitrust Litigation, an antitrust case alleging that defendant banks colluded to misreport and manipulate LIBOR.  This litigation has already resulted in partial settlements totaling approximately $187 million, which collectively represent the largest historical class-wide recovery for a “futures only” settlement class.
  • Special fiduciary representation for the exchange-based class in In re Foreign Exchange Benchmark Rates Antitrust Litigation for a putative class of participants who traded futures and options in the FX market.  The case has already resulted in partial settlements of more than $2.3 billion.
  • Counsel in the benchmark antitrust litigation In re Commodity Exchange, Inc., Gold Futures and Options Trading Litigation, on behalf of a putative class of gold derivative traders.  The case has resulted in settlements of $152 million.
  • Selected by the Court as co-lead counsel in In re JPMorgan Treasury Futures Spoofing Litigation, alleging that defendants manipulated U.S. Treasury futures for more than a decade and that this conduct contributed to the bank’s recent $920 million settlement with the DOJ, CFTC, and SEC.  The case has a putative settlement of $15.7 million.
  • Court appointed Executive committee member and class counsel in In re Cattle Antitrust Litigation, representing cattle producers and cattle futures traders.  The suit alleges that the “Big 4” meatpacking firms conspired to suppress prices for fed cattle and manipulated live cattle futures traded on the Chicago Mercantile Exchange.
  • Representation of exchange-based investors in Shak v. JPMorgan Chase & Co., alleging monopolization and manipulation of the silver futures market in violation of federal antitrust and commodity exchange laws.  The parties successfully reached a private settlement.  The case preceded a related Department of Justice criminal investigation into JPMorgan that remains ongoing.
  • Counsel in In re Deutsche Bank Spoofing Litigation on behalf of a putative class of investors alleging manipulation through “spoofing” of U.S. Treasury futures traded on the Chicago Board of Trade and Eurodollar futures traded on the Chicago Mercantile Exchange.
  • Court appointed to the Executive Committee and class counsel in In re Bank of Nova Scotia Spoofing Litigation, alleging that defendants manipulated precious metals futures traded on the New York Mercantile Exchange and the Commodity Exchange, Inc.
  • Representation of a putative class of exchange-based investors in Dennis v. The Andersons, Inc. et al., alleging monopolization and manipulation of Chicago Board of Trade soft red winter wheat futures contracts in violation of federal antitrust and commodity exchange laws
  • Court appointed Discovery Committee Co-Chair in In re Effexor XR Antitrust Litigation for a putative class of direct purchasers of brand name and generic equivalents of extended-release venlafaxine hydrochloride capsules against drug manufacturers.  Among the claims, Defendants are alleged to have delayed market entry of generic versions and entered into reverse payment settlements.
  • Representation as sole lead counsel in In re North Sea Brent Crude Oil Futures Litigation.

 Some of Ms. Lerner's other relevant experience includes:
  • Representation of a whistleblower in Anonymous, et ano. v. Moody's Corporation, et al., No. 103997/2012 (Sup. Ct. N.Y. Cty. and First Dept.), alleging millions of dollars of tax fraud using a sham captive insurance company for over a decade regarding domestic and international transactions. The litigation settled for $8.5 million.
  • Maverick v. Valeant Pharmaceuticals International, Inc., alleging that Valeant materially misrepresented its business model, touting artificial and unsustainable growth that was enabled by the company’s deceptive and illegal conduct.

Prior to joining KM, Ms. Lerner was of counsel at McDonough, Korn & Eichhorn, where she handled cases up to and including at trial.

Ms. Lerner is actively involved in promoting volunteerism in the legal community and through women’s organizations and is an advocate for diversity and inclusion and is a member of Women Antitrust Plaintiffs’ Attorneys (WAPA), an organization for female attorneys who focus their legal practice on representing businesses injured by cartels or other anticompetitive activities.  Finally, in addition to her legal practice and activities, Ms. Lerner has served as a member of the Board of Directors for several charitable organizations.  


National Law Journal Elite Women of the Plaintiffs Bar, 2022-2023
Top Rated Antitrust Litigation Attorney, Super Lawyers, 2021-2023
Top Women Attorneys in The New York Metro Area, American Registry, 2021-2022
Law360's Competition Editorial Advisory Board, 2022-2023