Leo Caseria is Co-Chair of both the firm’s Antitrust and Competition Practice Group and Governmental Practice and a partner in the Washington, D.C. and Los Angeles offices.

Areas of Practice

Leo represents clients in complex antitrust litigation, federal and state antitrust investigations, and government merger reviews. He has favorably resolved numerous matters for defendants at an early stage, including cases or investigations involving claims of conspiracy, monopolization, and price gouging. He has represented clients in a broad variety of industries, including cement, concrete, grocery, multifamily, automotive software, consumer electronics, fashion, beauty, and apparel.

Leo has particular expertise in the construction materials sector, where he has led the representation of producers of cement, ready-mixed concrete, and aggregates in connection with merger investigations brought by DOJ, FTC, and state enforcers. He has met with and presented to leaders at both DOJ and FTC in merger investigations, including FTC commissioners in connection with a Second Request. He has also represented clients in the construction materials industry in antitrust litigation and conduct investigation matters, and has provided compliance training presentations tailored to the construction materials industry on dozens of occasions. Leo’s representative clients in this space include CalPortland Company, Knife River, Chaney Enterprises, Builder’s Supply, and NRMCA

Leo has been ranked as a leading antitrust lawyer by Super Lawyers, Global Competition Review’s Who’s Who Legal, and Legal 500. He also serves as co-chair for the Books and Treatises Committee of the 9,000 member ABA Antitrust Law Section, a position he has held since 2016.



Representative Engagements:


  • Defending Realty One Group, Inc. against antitrust claims relating to alleged conspiracy to fix buyer broker commissions on residential real estate transactions. 
  • Defending Essex Property Trust (NYSE: ESS) against antitrust claims relating to alleged conspiracy to fix rental rates for multifamily apartment units. Competitors allegedly carried out the conspiracy using industry software and algorithm provided by RealPage. In re RealPage, Inc. Rental Software Antitrust Litigation (No. II), Case No. 23-3071 (M.D. Tenn.)
  • Defending Cyient, Inc. against antitrust claims brought by a putative class of aerospace engineers alleging a “no-poach” conspiracy between employers not to hire from each other from 2011 to the present. Borozny et al. v. Raytheon Technologies Corporation, Pratt & Whitney Division, et al., Case No 3:21-cv-01657 (D. Conn.).
  • Defending Hartford HealthCare Corporation against monopolization claims brought by competitor Saint Francis Hospital and Medical Center in federal court, and also against related class action brought by a putative class of individuals enrolled in commercial health plans. Saint Francis Hospital and Medical Center, Inc. v. Hartford Healthcare Corporation, Case No. 3:22-cv-00050-AVC (D. Conn.) and John Brown et al. v. Hartford HealthCare Corp., Case No. HHD-CV22-6152239-S (Superior Court of the Judicial District of Hartford).
  • Defending honey importer Export Packers Company Limited dba Odem International against an antitrust and RICO class action brought by a putative class of U.S. domestic beekeepers, relating to a purported conspiracy to sell foreign fake honey. All claims dismissed. Henry’s Bullfrog Bees v. Sunland Trading, Inc., Case No. 2:21-CV-00582-TLN-CKD (E.D. Cal. Order dated Feb. 23, 2022).
  • Defended The Reynolds and Reynolds Company against state and federal antitrust claims relating to data management system access. Monopolization and attempted monopolization claims dismissed at pleading stage. Motor Vehicle Software Corporation v. CDK Global, Inc., Case No. 17-896 (C.D. Cal. Order dated Oct. 2, 2017). Motion for summary judgment on conspiracy claims partially granted, eliminating majority of remaining potential liability. In re Dealer Management Systems Antitrust Litigation, Case No. 18-864 (N.D. Ill. Order dated Jun. 29, 2023).
  • Defending JRK Residential Group, Inc. against putative class action alleging price gouging of apartment rental rates in California following wildfire emergencies. Felker v. JRK Residential Group, Inc., Case No. SCV-267587 (Sonoma County Superior Court).
  • Representing cement producer CalPortland Company in antitrust case against four major railroads accused of allegedly price-fixing rate-based rail fuel surcharges. CalPortland Company v. BNSF Railway Company, Case No. 2:20-cv-03659 (C.D. Cal.).
  • Co-lead trial counsel for defendants in two-month antitrust trial in 2019 before Judge Edward Davila in case involving alleged price-fixing and market allocation claims relating to telescopes. Successfully obtained summary judgment on below-cost pricing and refusal to deal issues prior to trial. Optronic Technologies Inc. v. Ningbo Sunny Electronic Co. Ltd. et al., Case No. 5:16-cv-06370 (N.D. Cal. Order dated Sept. 20, 2019).
  • Defended CalPortland Company against False Claims Act claims premised on alleged conspiracy to fix prices and allocate markets relating to cement, concrete and asphalt. All claims dismissed; affirmed by Ninth Circuit. S. ex rel. Rune Kraft v. CalPortland Construction, Case No. 16-4479 (C.D. Cal. order dated Mar. 9, 2018), aff’d, Case No. 18-55594 (9th Cir. opinion dated Apr. 7, 2020).
  • Defended Save Mart against putative class action alleging price gouging of eggs in California. Plaintiff asserted a single claim under California’s Unfair Competition Law, Cal. Bus. & Prof. Code section 17200, predicated upon an alleged violation of California Penal Code section 396, which prohibits price gouging. Claim against Save Mart was voluntarily dismissed after Save Mart filed a motion to dismiss. Fraser v. Cal-Maine Foods, Inc., Case No. 20-2733 (N.D. Cal.).
  • Defended Amerifoods against putative class action alleging price gouging of eggs in California. Plaintiff asserted claims under California’s Unfair Competition Law, Cal. Bus. & Prof. Code section 17200, predicated upon an alleged violation of California Penal Code section 396, which prohibits price gouging. Claims against Amerifoods voluntarily dismissed. Elander v. Rose Acre Farms, Inc., Case No. 20STCV33673 (Los Angeles County Superior Court).

Merger Review

Conduct Investigations

  • 2022: Representing client in connection with confidential investigation by Washington attorney general relating to alleged antitrust conspiracy.
  • 2022: Representing third parties in connection with federal antitrust investigations concerning alleged anticompetitive conduct by technology companies.
  • 2022: Represented Smart & Final Stores, LLC and favorably resolved California attorney general investigation relating to alleged price gouging of eggs. People v. Smart & Final Stores, LLC, Case No. 22CIV01378 (Superior Court of the State of California, County of San Mateo).  https://www.law360.com/articles/1481365/grocery-chain-pays-175k-in-calif-s-covid-price-gouge-suit
  • 2020-2021: Represented several grocery store chains and favorably resolved confidential investigations by CA, NV, OR, and WA attorneys general, as well as local district attorneys, relating to alleged price gouging of eggs, water, toilet paper, and other food and grocery items.



  • Competition Future Leader, GCR Who’s Who Legal, 2021-2023
  • Next Generation Lawyers, Legal 500, 2019-2023
  • Antitrust, Legal 500, 2015, 2017, 2019-2023
  • Southern California Super Lawyer, Super Lawyers, 2021-2023
  • Southern California Rising Star, Super Lawyers, 2018-2020
  • Legal500 US Next Generation



Antitrust Law Blog Posts

Media Mentions

Speaking Engagements

  • “Antitrust…Opening the Gates,” National Ready-Mixed Concrete Association’s ConcreteWorks conference, Denver, Colorado, October 1, 2022
  • “Non-Competes and Non-Solicitation Clauses: What You Need to Know,” Association of Corporate Counsel New York chapter Annual Meeting, New York City, New York, September 21, 2022
  • “The Price is Right: Examining Antitrust and Pricing Issues in the Hospitality Industry,” Sheppard Mullin Webinar, May 25, 2021
  • "B2B Noncompetes and the Rule of Reason," Los Angeles County Bar Association Webinar, October 8, 2020
  • “Trending Legal Issues in the Retail Industry,” Sheppard Mullin Webinar, June 16, 2020




  • Co-Chair, Books and Treatises Committee, ABA Section of Antitrust Law, 2016-2024


J.D., Columbia Law School, 2005, Harlan Fiske Stone Scholar

B.A., University of California, Los Angeles, 2002


  • California
  • District of Columbia
  • U.S. Court for the Ninth Circuit
  • U.S. District Court, Central District of California
  • U.S. District Court, Eastern District of California
  • U.S. District Court, Northern District of California
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