Mark Nadeau is an advocate involved in complex commercial cases throughout the United States and has represented clients in many high-profile disputes.

Amongst the cases is significant industry focused work involving television, aviation, real estate hospitality, energy, trade secret and unfair business practice matters. His work in the energy sector has involved disputes concerning off-shore platform construction and insurance issues, nuclear plant and rod exchange programs, pipeline line siting and failures, drilling and extraction issues, as well as take or pay litigation. He successfully defeated a natural gas "cost of service gas" program involving long-term hedging of gas before five state public utilities commissions. He has served as lead counsel in high-profile satellite television multibillion-dollar disputes involving retransmission and antitrust issues. On behalf of several aviation and launch-system clients, he has worked on issues involving rocket technology, joint venture disputes, cockpit avionics, license and patent claims, airworthiness, airframe and engine performance financing. With an extensive background in all types of real estate disputes, Mark has acted as lead counsel on several multi-party construction and hospitality cases involving the acquisition, development, financing, operation, and management of hotels, resorts, spas and golf courses. He has defended many class action suits.

Mark received recognition by Martindale Hubbell as an AV Preeminent Lawyer with the highest possible rating in both Legal Ability and Ethical Standards reflecting the confidential opinions of members of the Bar and Judiciary. He was also named a Top 100 Lawyer in Arizona for 2020.

Beyond a very active litigation practice in the United States, his international arbitration practice spans Europe, Asia and South America. Mark is widely recognized as a leading commentator and has chaired numerous symposia on international dispute resolution.

At DLA Piper, Mark is the founding partner of the Phoenix office, where he now acts as the co-managing partner and chair of the office's litigation department. He is currently on DLA Piper's North American Pro Bono Committee. He is a former member of DLA Piper's Policy Committee and was the National Co-Chair for Business and Commercial Litigation.