Diane Hazel is a former government enforcer with the Federal Trade Commission’s Bureau of Competition and the Colorado Attorney General’s Office. She advises companies in complex, high-stakes antitrust litigation and investigations, drawing on her enforcement background to anticipate agency priorities and shape effective defense strategies from the outset.

Diane represents clients in major antitrust class actions and multidistrict litigation, as well as in investigations brought by the FTC, DOJ, and state attorneys general. She leads high-stakes matters through all phases of litigation, including case inception, dispositive motions, discovery, class certification, trial, and appeals. She practices in Colorado state courts and federal courts throughout the country. Poised and responsive in the courtroom, she is a clear and persuasive advocate. Diane is particularly adept at advancing case strategies that are both effective and nimble in response to evolving case dynamics. She is known for her creative approach to litigation, developing innovative arguments and analyzing complex issues from multiple angles to deliver strategic and effective advocacy. As part of her overall case management, Diane proactively identifies and explores alternative paths to resolution when they align with the client’s objectives and business needs.

She defends clients against allegations of price-fixing, market allocation, monopolization, and other antitrust claims, guiding matters from initial inquiry through discovery, dispositive motions, and trial. She works with companies across industries, including technology, life sciences, healthcare, manufacturing, and energy, and counsels on antitrust and consumer protection issues that arise in the ordinary course of business. Her work includes advising on competitor collaborations, information-sharing, distribution arrangements, pricing practices, and merger-related requirements, including Hart-Scott-Rodino filings and regulatory review. Diane partners with clients to understand their business goals and assess legal risks to inform strategic decision-making.

Diane’s experience inside government informs how she approaches advocacy and risk. Before returning to private practice, she served as first assistant attorney general in the Colorado Attorney General’s Office, where she led the Antitrust Unit. In that role, she supervised complex investigations and merger reviews, coordinated with federal and multistate enforcement partners, and helped shape the state’s competition enforcement priorities. She also served in the FTC’s Bureau of Competition, where she investigated and litigated antitrust matters in the healthcare and pharmaceutical sectors, including merger challenges and conduct investigations. She brings a practical understanding of how agencies assess and evaluate competitive effects and make enforcement decisions, and she uses that insight to position clients effectively.