Sidley Austin LLP

Co-led by New York-based Ellen Dunn and Chicago-based Thomas Cunningham, the insurance practice at Sidley Austin LLP is known for handling reinsurance disputes, regulatory investigations, and coverage litigation concerning COVID-19 business interruption cases. The team often represents insurers in court proceedings. Dunn specializes in advising on the regulatory aspect of disputes, while Cunningham has expertise concerning property and casualty, and life insurance matters, as well as asbestos-related claims. Other significant members of the team based in Chicago are Brian Kavanaugh, who is regarded as an expert in advising clients in health insurance disputes, and Christopher Assise, who boasts strong knowledge of rental reimbursement coverage litigation. In 2025, Eric Mattson retired from the firm, after longstanding experience defending insurers in class action lawsuits.