Jon Cieslak focuses on antitrust and white collar criminal defense litigation. Mr. Cieslak has extensive experience with all manner of civil antitrust claims, including claims under the Sherman Act, California’s Cartwright Act, and other state competition laws. Mr. Cieslak has substantial experience as a white collar criminal defense lawyer, particularly in antitrust matters. He has defended companies and C-level executives in price-fixing and bid-rigging prosecutions brought by the US Department of Justice (DOJ), has represented clients in DOJ investigations involving no poaching claims, and persuaded the DOJ to close investigations without charges.

Mr. Cieslak has represented clients in litigation asserting both cartel and monopolization claims in a variety of industries, including electronics, manufacturing, travel, media, and the gig economy. He has defended clients in multidistrict litigation, direct purchaser class actions, indirect purchaser class actions, individual actions, and on appeal. He also has extensive experience litigating on behalf of foreign companies in U.S. courts, including disputes involving the Foreign Trade Antitrust Improvements Act.

In addition, Mr. Cieslak has defended corporate clients in both federal and state courts against a variety of charges, including fraud, healthcare fraud, accounting fraud, and money laundering. He also routinely assists companies with internal investigations and whistleblower complaints related to antitrust, accounting, healthcare, the Foreign Corrupt Practices Act, and other issues.

Mr. Cieslak started his legal career as a clerk to the Honorable Jeffrey T. Miller, United States District Judge for the Southern District of California.

Mr. Cieslak maintains a healthy pro bono practice as well. He has represented children in immigration custody seeking due process rights, victims of fraudulent mortgage modification services, clients seeking Social Security benefits, and veterans, among others.


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