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Jon Cieslak

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Phone: +1-858-964-4589

4275 Executive Square #200
La Jolla, California 92037

Super Lawyers Rising Stars

Jon Cieslak represents clients in complex business litigation and white collar criminal defense, focusing on antitrust and competition law claims, prosecutions, and investigations.

He 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. Jon has represented clients large and small 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. Jon also has extensive experience litigating on behalf of foreign companies in US courts, including disputes involving the Foreign Trade Antitrust Improvements Act (FTAIA).

Jon also has substantial experience as a white collar criminal defense lawyer, in both antitrust and other matters. He has defended companies and C-level executives in price-fixing and bid-rigging prosecutions brought by the US Department of Justice (DOJ). He has represented clients in DOJ investigations involving no poaching claims, and persuaded DOJ to close investigations without charges. In addition, Jon has defended corporate clients in both federal and state courts against a variety of charges, including fraud, healthcare fraud, accounting fraud, and money laundering. Jon also routinely assists companies with internal investigations and whistleblower complaints related to antitrust, accounting, healthcare, Foreign Corrupt Practices Act (FCPA), and other issues.

In addition to antitrust litigation, Jon regularly represents clients in other complex business litigation, including those involving breach of contract, unfair competition, false advertising, Lanham Act, securities fraud, and trade secret claims.

Jon has always maintained 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.

Before joining Bona Law, Jon practiced antitrust law, complex business litigation, and white collar criminal defense at Cooley LLP for nearly a decade. He started his legal career as a clerk to the Honorable Jeffrey T. Miller, United States District Judge for the Southern District of California.


J.D., UCLA School of Law

A.B., Princeton University

Judicial Clerkship

United States District Court for the Southern District of California for Hon. Jeffrey T. Miller

Representative Matters
  • Antitrust Litigation
    • In re Lithium Ion Batteries Antitrust Litigation - Defended a global electronics company in direct purchaser and indirect purchaser MDL class actions asserting price-fixing and bid-rigging claims.
    • Prosterman v. ATPCO, et al. - Defended technology company in class action alleging price-fixing claims related to airline fares, resulting in dismissal of all claims (affirmed on appeal).
    • Bona Fide Conglomerate, Inc. v. SourceAmerica, et al. - Defended non-profit organization against price-fixing claims related to government procurement program, resulting in dismissal of all claims (affirmed on appeal).
    • In re California Bail Bonds Antitrust Litigation - Defended clients in consolidated class actions alleging price fixing of bail bonds.
    • In re Local TV Advertising Antitrust Litigation - Defended media company in MDL class action alleging price-fixing and unlawful information sharing by local television stations.
    • Represented client in litigation and arbitration asserting monopolization and unfair competition in trademark registration services industry.
    • Defended major gig-economy company against monopolization claims, resulting in dismissal of claims.
  • White Collar Criminal Defense and Internal Investigations
    • Defended CEO of a major electronics manufacturer in a precedent-setting antitrust prosecution involving price-fixing claims brought by DOJ.
    • Represented Fortune 500 company in no-poach investigation by DOJ, resulting in closure of investigation without charges.
    • Defended CEO of payment processing company against money laundering charges, resulting in dismissal of all charges.
    • Defended healthcare company and CEO against healthcare fraud charges.
    • Represented drug development company regarding investigation of potential misstatements to investor.
    • Represented technology company regarding investigation of potential accounting fraud.
    • Represented technology company regarding whistleblower complaint alleging accounting fraud.
    • Represented development company regarding FCPA investigation.
Jurisdictions Admitted to Practice California
United States District Court for the Southern District of California
United States District Court for the Central District of California
United States District Court for the Eastern District of California
United States District Court for the Northern District of California
United States Court of Appeal for the Ninth Circuit