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Aaron Zigler is a Partner at Keller Lenkner LLC. He represents consumers, whistleblowers and businesses as plaintiffs in high-stakes litigation concerning computer technology, internet privacy, insurance, pharmaceuticals and other matters.

Prior to joining Keller Lenkner, Aaron was a partner at Korein Tillery LLC, where he managed all aspects of high-stakes litigation for nearly two decades.

Aaron has received the recognition of his peers through a Martindale-Hubbell AV Preeminent peer rating and multi-year selection as a Super Lawyers “Rising Star”. Aaron has also been honored as a finalist for Public Citizen’s Trial Lawyer of the Year award. He is a member of the American Society of Legal Writers.

Prior to his legal career, Aaron worked in computer security for a Fortune 500 company. He continued that interest by concentrating his legal studies and research in computer technology. That experience and study have proved invaluable as Aaron has pursued numerous cases concerning the abuse of computer technology, including In re: Google Inc. St. View Elec. Commc’ns Litig., 733 F. Supp. 2d 1381 (J.P.M.L. 2010) and In re: Facebook Use of Name & Likeness Litig., 816 F.Supp.2d 1380 (J.P.M.L. 2011).

Other notable cases for which Aaron has been responsible include:

  • Senne v. The Office of the Comm’r of Baseball. Minor league baseball players brought this wage-and-hour claim alleging that their teams failed to pay minimum wage and overtime as required by state and federal law. Plaintiffs won certification of a Fair Labor Standards Actn (FLSA) collective action and a Rule 23 class of minor league players who played in California. No. 14-CV-00608-JCS, 2017 WL 897338 (N.D. Cal. Mar. 7, 2017). On appeal, the Ninth Circuit affirmed certification of those actions and reversed the district court’s denial of Rule 23 classes of minor league players who played in Florida and Arizona. 934 F.3d 918 (9th Cir. 2019).
  • Axiom Investment Advisors, LLC v. Barclays Bank PLC. Plaintiffs alleged that when Barclays was presented with a foreign currency order, its trading algorithms intentionally delayed execution by several hundred milliseconds to track market developments. If the trade order would be too profitable to the client, Barclays would renege on the agreed price and reject the trade, or would fill the order at a less-favorable price. The matter settled for $50 million on behalf of a nationwide class. No. 15-cv-9323-LGS (S.D.N.Y. July 19, 2017).
  • United States ex rel. Garbe v. Kmart Corp. Kmart pharmacies charged low, flat-rate prices for certain generic drug prescriptions but charged significantly higher prices to customers with Medicare or Medicaid coverage. One of its pharmacists brought this whistleblower action, alleging that this practice violated the False Claims Act and defrauded federal and state governments of millions of dollars each year. The district court denied Kmart’s motions for summary judgment. 73 F. Supp. 3d 1002 (S.D. Ill. 2014). The Seventh Circuit affirmed, finding that the price given to Kmart pharmacy customers paying out-of-pocket should have been passed along to government payors. 824 F.3d 632 (7th Cir. 2016). Following additional motions practice, the case settled on the eve of trial, with Kmart agreeing to pay $59 million.
  • City of Greenville v. Syngenta Crop Prot., Inc. A class of public and private water providers throughout the country alleged that the herbicide atrazine—one of the most-used herbicides in the United States and one that has been linked to hormonal changes in animals—persistently invaded their water supplies. After almost eight years of litigation in state and federal court, the matter settled for $105 million. 904 F. Supp. 2d 902 (S.D. Ill. 2012).
  • Hoormann v. SmithKline Beecham Corp. A nationwide class of purchasers alleged that SmithKline Beecham promoted Paxil and Paxil CR for prescription to children and adolescents, despite actual knowledge that these drugs exposed children and adolescents to dangerous side effects while also failing to treat their symptoms. The settlement established a $63.8 million fund to reimburse class members 100% of their out-of-pocket expenses. 2007 WL 1591510 (Ill. Cir. Ct. May 17, 2007). The New York Attorney General’s Office settled its lawsuit concerning the same conduct for a $2.5 million fine.
  • Prather v. Pfizer Inc. Pfizer marketed its anti-diabetes drug Rezulin as a “breakthrough” that was as “safe as a placebo.” But over the course of the three years Rezulin was on the market, many people died and many more were seriously injured as a result of its use. Because of the harmful effects of Rezulin, thousands of personal injury cases and 50 class action cases were filed. Of the class actions, only this one—alleging unfair business practices under the New Jersey Consumer Fraud Act—lead to any recovery. The settlement established a $60 million fund to pay 85% of plaintiffs’ out-of-pocket expenses for Rezulin and an additional $20 million cy pres award to finance diabetes research. No. 02-L-480 (Ill. Cir. Ct. Dec. 2, 2004). This settlement was used on the floor of the Senate as an example of why state-court class actions serve the public good. See 150 Cong. Rec. 92, S7714-17 (July 7, 2004 statement of Sen. Durbin); 151 Cong. Rec. 12, S1082-85 (February 8, 2005 statement of Sen. Durbin).

Aaron earned his J.D. from St. Louis University School of Law and his undergraduate degrees from Columbia College.