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John Holler

John Holler

Senior Associate

John Holler's practice focuses on helping clients navigate complex antitrust issues. He represents clients across a range of industries in government merger and conduct investigations and in civil antitrust litigation. Prior to joining Arnold & Porter, John worked as a trial attorney at the Antitrust Division of the U.S. Department of Justice (DOJ). While at DOJ Antitrust, he played a key role in nearly a dozen civil antitrust investigations and two merger litigations (Anthem-Cigna and Sabre-Farelogix).

John maintains an active pro bono practice, focused on representing clients in immigration-related proceedings.

John is a graduate of The University of Chicago Law School and Pomona College. While in law school, he interned at DOJ Antitrust's Chicago office. Between college and law school, he was an honors paralegal in the Federal Trade Commission's Bureau of Competition, working on antitrust matters and for the Director of the Bureau of Competition.


  • Thermo Fisher Scientific Inc. in its US$17.4 billion purchase of PPD Inc.
  • Penguin Random House in its US$2.2 billion attempted acquisition of Simon & Schuster.
  • Penguin Random House in defense of purported class actions alleging that Penguin Random House and other publishers conspired with Amazon to restrain competition in the sale of eBooks and physical books, as well as a Robinson-Patman Act price discrimination claim related to the sale of physical books to booksellers.
  • Kroger in successfully defending against federal and state litigation brought by state attorneys general to enjoin a US$4 billion special dividend payment by Albertsons announced concurrently with its proposed merger with Kroger.


  • U.S. Department of Justice, Attorney General’s Award for Distinguished Service (2019)
  • U.S. Department of Justice, Antitrust Division, Award of Distinction (2017, 2018)



  • J.D., with honors, University of Chicago Law School, 2016
  • B.A., International Relations, Pomona College, 2011, cum laude


  • New York
  • Illinois
  • U.S. District Court, Southern District of New York

Government & Military Service

  • Trial Attorney, U.S. Department of Justice, Antitrust Division (2016–2020)
  • Honors Paralegal, Federal Trade Commission, Bureau of Competition (2011–2013)


  • Co-author of Thomson Reuters’ Antitrust Adviser chapter focused on DOJ Antitrust’s civil and criminal non-merger enforcement