Sheppard‘s antitrust and competition practice is based in its Washington DC office and is led by Leo Caseria and Ann O’Brien, co-chairs of the firm’s Antitrust & Competition Group. The team is noted for defending complex civil and criminal antitrust matters, including cartel, no-poach, wage-fixing, and monopolization claims, as well as high-profile government investigations and class actions. Caseria brings deep experience in bet-the-company litigation and regulatory strategy, while O’Brien leads the firm’s criminal antitrust and cartel work, regularly handling parallel civil, criminal, and agency proceedings
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Testimonials
Collated independently by Legal 500 research team.
- In the complex and rapidly evolving landscape of antitrust litigation—particularly as it pertains to the multifamily housing industry, the following attorneys stand out: Leo Caseria is consistently available for high-level strategy and granular questions alike. This 1:1 relationship ensures that the legal advice is never "templated"; it is always filtered through a deep understanding of our specific organizational needs as they relate to the current status of antitrust matters in the multifamily housing industry. His understanding of antitrust and cartel matters is exceptional. His capabilities go beyond traditional antitrust litigation; he understands the mechanics of how property owners and managers use technology and how those practices are viewed by regulators. Mark Rackers stands out not just for his depth of understanding of commercial litigation, but for the depth of the partnership he builds with his clients. Tom Dillickrath's former experience as Deputy Chief Trial Counsel at the Federal Trade Commission (FTC) allows him a "look behind the curtain" that few other attorneys can match. Each of these attorneys invests the time to understand the specific pressures of the multifamily sector, making them feel like an extension of my own team rather than an outside vendor. While other firms might prioritize volume, they prioritize the long-term health of our organization, providing sophisticated counsel that is as authentic as it is effective.
- In the complex and rapidly evolving landscape of antitrust litigation—particularly as it pertains to the multifamily housing industry, the following attorneys stand out: Leo Caseria is consistently available for high-level strategy and granular questions alike. This 1:1 relationship ensures that the legal advice is never "templated"; it is always filtered through a deep understanding of our specific organizational needs as they relate to the current status of antitrust matters in the multifamily housing industry. His understanding of antitrust and cartel matters is exceptional. His capabilities go beyond traditional antitrust litigation; he understands the mechanics of how property owners and managers use technology and how those practices are viewed by regulators. Mark Rackers stands out not just for his depth of understanding of commercial litigation, but for the depth of the partnership he builds with his clients. Tom Dillickrath's former experience as Deputy Chief Trial Counsel at the Federal Trade Commission (FTC) allows him a "look behind the curtain" that few other attorneys can match. Each of these attorneys invests the time to understand the specific pressures of the multifamily sector, making them feel like an extension of my own team rather than an outside vendor. While other firms might prioritize volume, they prioritize the long-term health of our organization, providing sophisticated counsel that is as authentic as it is effective.
- In the complex and rapidly evolving landscape of antitrust litigation—particularly as it pertains to the multifamily housing industry, the following attorneys stand out: Leo Caseria is consistently available for high-level strategy and granular questions alike. This 1:1 relationship ensures that the legal advice is never "templated"; it is always filtered through a deep understanding of our specific organizational needs as they relate to the current status of antitrust matters in the multifamily housing industry. His understanding of antitrust and cartel matters is exceptional. His capabilities go beyond traditional antitrust litigation; he understands the mechanics of how property owners and managers use technology and how those practices are viewed by regulators. Mark Rackers stands out not just for his depth of understanding of commercial litigation, but for the depth of the partnership he builds with his clients. Tom Dillickrath's former experience as Deputy Chief Trial Counsel at the Federal Trade Commission (FTC) allows him a "look behind the curtain" that few other attorneys can match. Each of these attorneys invests the time to understand the specific pressures of the multifamily sector, making them feel like an extension of my own team rather than an outside vendor. While other firms might prioritize volume, they prioritize the long-term health of our organization, providing sophisticated counsel that is as authentic as it is effective.
- What sets this practice apart is the transition from a standard attorney-client dynamic to a true professional partnership. In a field where interactions can often feel transactional, I have developed a one-on-one, collaborative relationship with a subject matter expert who is deeply embedded in the antitrust sector. Potential clients should know that the team’s strength lies in their deep understanding of antitrust laws. They don’t just identify legal roadblocks; they provide the "how-to" for navigating them and how to avoid them.
Key clients
- Fluor Federal Services, Inc.
- National Pipe & Plastics, Inc. (a CRH Company)
- Progressive Insurance
- CalPortland
- Essex Property Trust
- Strava
Work highlights
Representing Fluor Federal Services, Inc. in the defense of a no poach antitrust class action filed in early October 2025 alleging that Fluor and five other disaster response contractors providing Federal Emergency Management Agency (FEMA) Technical Assistance Contracting services under Fluor’s prime contract colluded not to poach or solicit each other’s employees and fix wages in violation of both the Sherman Act and the Florida Antitrust Act.
Representing National Pipe & Plastics, Inc. (a CRH Americas Company) in the consolidated civil antitrust class actions In re: PVC Pipe Antitrust Litigation in the Northern District of Illinois alleging a years-long, conspiracy among major PVC pipe and fittings manufacturers and distributors to fix prices using OPIS, a Dow Jones publication, as a conduit to share information and collude.
Defending Progressive in the cases, Ferrier et al. v. State Farm Fire and Casualty Co. et al. and Canzoneri v. State Farm Fire and Casualty Co. et al, in Los Angeles Superior Court against dozens of insurance carriers on behalf of property owners impacted by the wildfires that devastated the Pacific Palisades, Malibu, and Altadena in January 2025.
Lawyers
Leading partners
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Practice head
Leo Caseria; Ann O'Brien