Michael P. Mayer

Michael Mayer is a litigation partner in Winston & Strawn’s Chicago office, focusing on complex commercial cases, antitrust disputes, class actions, intellectual property cases, tax disputes, securities cases, and white-collar criminal matters and investigations. He is also an adjunct professor at Northwestern University School of Law and teaches a course regarding pre-trial strategies.

Recognized by Chicago magazine and Super Lawyers as an Illinois “Rising Star” from 2009 through 2013. Mr. Mayer frequently represents highly visible clients in high-stakes litigation in federal and state courts around the country, including consumer electronics companies, retailers, technology companies, private equity firms, hedge funds, real estate investment trusts, pharmaceuticals, and manufacturers. Among his engagements, Mr. Mayer has successfully represented Motorola, LG Electronics, Ford Motor Company, and General Electric Company, among many other Fortune 500 companies, in matters ranging from less than $1 million to representations involving several billions of dollars.

Mr. Mayer has argued in front of various federal and state courts around the country. His experience includes the representation of clients in grand jury proceedings, civil and criminal appeals, and parallel proceedings and enforcement actions before a variety of federal regulators, including the Federal Trade Commission, the U.S. Securities and Exchange Commission, and the Department of Justice.

Representative Clients and Matters:


  • RockTenn CP, LLC: Defense of Section 1 Sherman Act claims regarding the containerboard industry. Kleen Products LLC v. Packaging Corporation of America, 1:10-cv-05711 (N.D. Ill.)
  • Motorola, Inc.: Defense of Section 1 Sherman Act claims with respect to technology intended to be used in the wireless communications industry. Prevailed on summary judgment, which was subsequently upheld by the Fifth Circuit Court of Appeals. Golden Bridge Technology, Inc. v. Motorola, Inc., 547 F.3d 266 (5th Cir. 2008); Golden Bridge Technology, Inc. v. Nokia, Inc., 2007 WL 2688487 (E.D. Tex. Sept. 11, 2007).
  • Chicago Bridge & Iron: Defense of merger case brought by the Federal Trade Commission, alleging violations of Section 7 of the Clayton Act and Section 5 of the FTC Act after CB&I purchased certain assets of Pit-Des Moines, Inc. Was part of the core trial team in the first consummated merger case tried in font of the FTC in more than two decades. In the Matter of Chicago Bridge & Iron Company et al., Docket No. 9300 (F.T.C.)
  • Adesa Inc.: Defense of antitrust claims brought under Sections 1 and 2 of the Sherman Act and Section 3 of the Clayton Act in the vehicle auction operator industry. After dismissing various claims at the outset of the case, the matter settled on favorable terms to Adesa. Kasp, Inc. v. Adesa, Inc., 2006 WL 385310 (E.D. Ky. Feb. 17, 2006).
  • Smurfit-Stone Container Corporation: Defense of federal nationwide class action and thousands of follow-on opt-out cases alleging price fixing claims in the corrugated container industry. In re Linerboard Antitrust Litigation, MDL 1261 (E.D. Pa.)
  • PPG Industries: Defense of federal nationwide class action lawsuit and six state class action lawsuits alleging price fixing claims in the automotive refinish paint industry. In re Automotive Refinishing Paint Antitrust Litig., MDL No. 1426 (E.D. Pa.)
  • Morton Grove Pharmaceuticals: Representation of drug manufacturer in pursuit of Walker Process antitrust claims against competitor in connection with megestrol acetate drug. Morton Grove Pharmaceuticals v. Par, 04-cv-7007 (N.D. Ill.)

Complex Commercial Disputes

  • LR Nelson Inc.: Successful defense of fraud claims brought against board members of LR Nelson Inc. Rubbermaid Incorporated v. Robert Bosch Tool Corporation et al., Case No. 09-1395 (C.D. Ill.)
  • Motorola: Prosecuted breach of contract claims against satellite phone manufacturer. Motorola, Inc. v. Iridium Satellite LLC et al., 2010 CH 05684 (Cook County Circuit Court).
  • Del Frisco’s Restaurant Group: Successful prosecution of claims against general contractor arising from construction defects in connection with the opening of a new restaurant.
  • Ford Motor Company: Defense of a contract claim brought by Ford’s diesel engine supplier. International Truck & Engine Co. v. Ford Motor Company, Case No. 2008 L 002148 (Cook County Circuit Court).
  • Aon Corporation: Defense of federal and state securities actions brought by shareholder, resulting in take nothing verdict. Anderson v. Aon Corp., 2012 WL 1034539 (7th Cir. March 29, 2012); Anderson v. Aon Corp., 2008 WL 4865574 (N.D. Ill. June 16, 2008); Anderson v. Aon Corp., 2008 WL 5388321 (N.D. Ill. Dec. 22, 2008); Anderson v. Aon Corp., 2011 U.S. Dist. Lexis 111217 (N.D. Ill. Sept. 29, 2011).
  • Aon Corporation: Prosecuted breach of contract claims against former Aon officer, resulting in favorable settlement. Aon Corp. v. Utley, 371 Ill. App. 3d 562, 863 N.E.2d 701 (Ill. App. Ct. 2006).
  • General Electric Company: Prosecuted breach of contract claim and replevin action against medical company, resulting in favorable judgment for GE. General Electric Company v. Apollo MRI, Inc., Case No. 2007 L 8336 (Cook County Circuit Court).
  • Motor Coach Industries International, Inc.: Defense of contract claim brought by its former parent, Viad. After a receiving a partial summary judgment award, the Motor Coach entities settled on favorable terms. Viad v. Motor Coach Industries Int’l, 2003 WL 22853414 (Del. Sup. Ct. 2003).

Intellectual Property

  • CPI Card Group: Successful defense in case asserting patent infringement claims involving gift card technology. Travel Tags Inc. v. UV Color, Inc. et al., 09-1619 (D. Minn.)
  • Morton Grove Pharmaceuticals: Successful defense of patent infringement claims involving patents relating to megestrol acetate, an appetite stimulant drug, resulting in a take nothing dismissal with prejudice. Morton Grove Pharmaceuticals v. Par,04-cv-7007 (N.D. Ill.)
  • Thomson Inc.: Obtained temporary restraining order in connection with a license dispute over patents relating to digital video recorders. Thomson, Inc. v. Macrovision Corp., No. 29D03-0611-PL-1144 (Hamilton Superior Court, Indiana).

White-Collar Criminal/Internal Investigations

  • Represented a high net-worth individual in connection with a federal grand jury investigation involving allegations of fraud.
  • Represented a hedge fund in connection with a SEC investigation involving insider trading.
  • Represented large institution in connection with a DOJ grand jury investigation involving federal RICO counts.
  • Represented private equity firm in connection with DOJ grand jury investigation.
  • Represented an engineering construction firm in connection with a DOJ grand jury investigation involving alleged price fixing and bid rigging.

Mr. Mayer received a B.S. in Aviation Technology and Operations, magna cum laude, from Western Michigan University in 1997 and a J.D., cum laude, from the University of Wisconsin Law School in 2000, where he was note and comment editor of the Wisconsin International Law Journal.

Honors & Awards

Mr. Mayer has been named by Chicago magazine and Super Lawyers as a “Rising Star” from 2009 through 2013. He also received recognition by the Coalition for the Homeless for his pro bono service for the homeless, and in 2014, Winston & Strawn was awarded “Chicago Litigation Department of the Year” in the National Law Journal for white collar defense.


In addition to his practice, Mr. Mayer is an active teacher. Since 2009, Mr. Mayer has served as an Adjunct Professor at Northwestern University School of Law, teaching a Pre-Trial Advocacy course that focuses on strategies involving pre-litigation, motion practice, discovery, and case development. Mr. Mayer frequently conducts training courses for summer associates on matters relating to taking depositions and providing oral arguments. He has also been a guest lecturer at the Kellogg School of Management, Northwestern University, speaking on antitrust issues.

Mr. Mayer is a member of the American Bar Association (including the Antitrust Section of the ABA) and the Chicago Bar Association. He serves as an investigator for the CBA’s Judicial Evaluation Committee.

Mr. Mayer actively participates in pro bono representation. He recently secured a sizeable settlement on behalf of an inmate seeking redress under a 42 U.S.C. 1983 claim. He also successfully represented a client as co-counsel with the Coalition for the Homeless in an appeal relating to a judgment in favor of his client in a sexual harassment suit against a former landlord. Mr. Mayer has also briefed and argued a criminal appeal before the Illinois Court of Appeals and represented pro bono clients in summary suspension hearings. In addition to his pro bono work, Mr. Mayer has served as a mentor in the firm’s Associate Mentoring Program and as an adviser in the firm’s Summer Associate Program.