John M. Tanski
{ Bio Portrait }

John Tanski is a skilled courtroom advocate with deep experience litigating antitrust, commercial and intellectual property claims. Leading domestic and international companies rely on John’s sound advice to help them navigate their most consequential business disputes. John has litigated some of the largest and most complex lawsuits in recent years, successfully defending multibillion-dollar individual and class claims in federal and state courts across the country and in multidistrict litigation. Clients praise John's “intellectual firepower” and describe him as “a valuable counselor” for “business clients as they weigh the pros and cons of the possible paths to follow.”

In the antitrust field, John is currently defending Tyson Foods against billion-dollar output reduction and index manipulation claims brought by three classes, more than one hundred individual plaintiffs, and multiple state attorneys general in the In re Broiler Chicken Antitrust Litigation and related matters. He has also represented international clients in the sprawling In re Automotive Parts Antitrust Litigation cartel case and defeated a nine-figure boycott claim against Stanley Black & Decker on summary judgment.

In commercial litigation, John is lead counsel for Alvogen in the multi-billion-dollar National Prescription Opiate multidistrict litigation and in related proceedings across the country. He has also successfully represented defendants in class actions involving a variety of products, from infant formula to financial products to insurance, and he regularly litigates claims of unfair trade practices, breach of contract, breach of fiduciary duty, and fraud.

John has a wide-ranging intellectual property litigation practice in which he has fought off claims of patent infringement, trade secret misappropriation and breach of patent license. Early in his Axinn career, John was part of the trial team that successfully defended Actavis against a ten-figure patent damages claim involving the blockbuster drug Neurontin®. More recently, John defeated a multi-billion-dollar lost profits claim against Hubbell in a case alleging the theft of wireless lighting technology trade secrets. 

John also maintains an active pro bono practice. The Second and Tenth Circuits have appointed John to represent indigent clients in federal appeals, and he has served as pro bono trial counsel in discrimination matters for the Connecticut Commission on Human Rights and Opportunities. In addition, John is the Vice Chairman of the Glastonbury Water Pollution Control Authority and a member of the Connecticut State Advisory Committee to the United States Commission on Civil Rights.

John is recognized in Best Lawyers in America in the areas of commercial litigation and antitrust litigation. He is a member of the Hartford Business Journal’s “40 Under Forty” class of 2019, and he was honored as a “New Leader in the Law” by the Connecticut Law Tribune in 2013. Before entering private practice, John served as a law clerk to the Honorable Paul J. Kelly, Jr. of the United States Court of Appeals for the Tenth Circuit.

More » « Less

Professional Activities

  • Connecticut Bar Association, Executive Committee Antitrust and Trade Regulation Section (2021-2022)
  • American Bar Association, Section of Litigation
  • US Court of Appeals for the Second Circuit, Pro Bono
  • Panel (2019 – 2022)


Antitrust Litigation

  • Represents Tyson Foods in the Broiler Chicken antitrust litigation in the United States District Court for the Northern District of Illinois.
  • Represents Nishikawa Rubber Company in the Auto Parts antitrust MDL in the United States District Court for the Eastern District of Michigan.
  • Won dismissal of all claims against Friedrich Boysen GmbH & Co. KG in the Auto Parts antitrust class action MDL in the United States District Court for the Eastern District of Michigan.
  • Won unanimous affirmance in the Fourth Circuit of summary judgment defeating a nine-figure antitrust claim alleging that Stanley Black & Decker and other table saw manufacturers engaged in a group boycott of table saw safety technology.

Intellectual Property Litigation

  • Won summary judgment of no lost profits for Hubbell erasing a ten-figure trade secret damages claim relating to wireless lighting control systems in the United States District Court for the District of Connecticut.
  • Won a temporary restraining order preventing Lego from blocking the import of construction toys by Canadian manufacturer Mega Brands in the United States District Court for the Central District of California.
  • Served on a trial team that obtained a favorable resolution for Actavis of ten-figure patent infringement claims by Pfizer relating to the drug Gabapentin in the United States District Court for the District of New Jersey.

Other Complex Commercial Litigation

  • Represents a generic pharmaceutical manufacturer in the Opioid litigation In the United States District Court for the Northern District of Ohio and in Pennsylvania state court.
  • Successfully briefed an appeal on behalf of national insurance broker Brown & Brown, winning unanimous affirmance in the Connecticut Supreme Court of summary judgment on all claims brought by Blumberg Associates Worldwide. He previously briefed and argued the case successfully in the Connecticut Appellate Court.
  • Won a preliminary injunction in the United States District Court for the Western District of Washington for health care benefit and payment solutions provider WEX Health (formerly Evolution1) requiring benefits administrator Flex-Plan Services, Inc. to continue to perform the parties’ contract after Flex-Plan sued WEX Health seeking early termination.
  • Won permission from the United States Court of Appeals for the Eleventh Circuit to take an interlocutory appeal of an order certifying a class for claims of false advertising against Mead Johnson, the maker of Enfamil LIPIL infant formula. Then persuaded the Judicial Panel on Multidistrict Litigation to transfer and consolidate similar class actions filed in districts across the country. Then obtained court approval of nationwide settlement of the consolidated claims, and then won unanimous affirmance of the settlement's approval in the Eleventh Circuit.


  • The Hartford Business Journal 40 Under Forty Class (2019)
  • Best Lawyers (2019 – 2023)
  • Super Lawyers (2013 – 2022)
  • In February of 2018, Axinn was nominated for Global Competition Review "Litigation of the Year – Cartel Defence" for its work on behalf of Nishikawa Rubber Company in the Auto Parts litigation. This award recognizes "creative, strategic and innovative litigation on behalf of a defendant in a private action for cartel damages."

  • In February of 2017, Axinn was nominated for Global Competition Review “Litigation of the Year – Non-Cartel Defence” for its work in winning summary judgment for Stanley Black & Decker in a lawsuit alleging that leading table saw manufacturers had conspired to boycott saw safety technology.
  • Connecticut Law Tribune – "New Leader in the Law" (2013)

Thought Leadership



  • JD – Columbia Law School (2006) Managing Editor, Columbia Journal of Transnational Law. James Kent Scholar. Harlan Fiske Stone Scholar. Simon H. Rifkind Prize. Lawrence S. Greenbaum Prize.
  • AB, cum laude – Princeton University (2003)


  • Connecticut
  • New York
  • US Court of Appeals for the Second Circuit
  • US Court of Appeals for the Fourth Circuit
  • US Court of Appeals for the Seventh Circuit
  • US Court of Appeals for the Tenth Circuit
  • US District Court District of Colorado
  • US District Court District of Connecticut
  • US District Court Southern District of New York
  • US District Court Eastern District of Michigan
  • US Supreme Court

By using the Axinn, Veltrop & Harkrider LLP website with cookies enabled on your browser, you agree to our use of cookies during your browsing experience. Learn more about our privacy policy.