TIM TREANOR is Managing Principal of the Treanor Law Firm. He founded the firm after 17 years as a partner of Sidley Austin LLP where he served for more than ten years as Global Co-Leader of the White Collar Defense and Investigations practice (ranked #2 in the world by Global Investigations Review in 2024 and 2025) until his departure from the firm at the end of 2024. Before Sidley, Tim served for nearly a decade as a federal prosecutor and senior unit supervisor in the Office of the U.S. Attorney for the Southern District of New York.
“Tim’s judgment is unassailable and impeccable.” Chambers USA
Tim has been recognized by numerous industry publications, including Law360’s national list of five White Collar MVPs. He is ranked by Chambers Global for FCPA and Chambers USA for both New York White-Collar Crime & Government Investigations and for Nationwide FCPA. In Chambers Global, he was described as a “very capable lawyer who is very responsive in terms of client demands. He is very experienced in interacting with authorities as well as able to handle the pressure that comes from high-stakes investigations.” Clients remarked to Martindale-Hubbell that “Tim is a first-rate lawyer. Very fine legal mind and very ethical.” Tim has been recognized since 2015 in Who’s Who Legal for Investigations and Business Crime Defence of Individuals and Corporates and since 2020 in The Best Lawyers in America for Criminal Defense: White-Collar Law. He has been listed in The Legal 500 US for Compliance and Investigations in Latin America; in Ethisphere among its “Attorneys Who Matter;” in Latinvex as an “FCPA and Fraud Leader” for Latin America; in the Irish Legal 100 as a leading lawyer of Irish heritage; and in Super Lawyers as a top-rated white collar crimes lawyer in New York.
Tim brings a thoughtful and tailored approach to his representations of clients. He is a forceful advocate who can fight tenaciously for his clients in court proceedings and before his adversaries, but when appropriate, can employ a practical, problem-solving approach. Tim regularly represents companies and executives before the U.S. Department of Justice (DOJ), including its various U.S. Attorney’s Offices, the Securities and Exchange Commission (SEC) and other federal civil enforcement agencies (FinCEN, OFAC, and BIS), banking regulators (Federal Reserve, OCC, and NYDFS), and state attorneys general. He has represented clients in a variety of industries, including financial services, insurance, life sciences, energy, and technology, and often has managed parallel criminal and civil proceedings and multi-jurisdictional matters involving foreign government agencies. Tim has helped many clients avoid adverse consequences in enforcement actions and has negotiated favorable dispositions with a range of agencies. He also has advised companies on the development of internal compliance programs and counseled clients in connection with potential compliance violations, particularly in the financial services industry or where there are national security implications, including in the areas of anti-money laundering (AML), including the Bank Secrecy Act (BSA), and anti-corruption (Foreign Corrupt Practices Act (FCPA)). Tim also has significant experience managing civil litigation under RICO, the Anti-Terrorism Act, and the False Claims Act.
Tim “rolls up his sleeves and gets to the facts. He is also a tough and very effective leader”
– Chambers Global
Prior to joining Sidley in 2008, Tim was an Assistant U.S. Attorney in the Office of the U.S. Attorney for the Southern District of New York (SDNY) for nine years, serving as Deputy Chief of the Organized Crime Unit, and at times, as Acting Chief of the Violent Crimes and Narcotics Units. For several years, he was a member of the Organized Crime and Terrorism Unit, and in that capacity, helped to execute the DOJ’s response to the terrorist attacks of September 11, 2001. Tim also worked closely with other prosecutors’ offices in New York, serving as Special Assistant Deputy Attorney General for the State of New York and earlier as a student prosecutor in the U.S. Attorney’s Office for the Eastern District of New York.
During his tenure at the U.S. Attorney’s Office, Tim established himself as one of the government’s most experienced and successful trial lawyers. He tried a dozen criminal cases and led the government teams in three major multi-month, multi-defendant trials. Tim also briefed and argued numerous cases before the U.S. Court of Appeals for the Second Circuit.
Tim was a founding partner of Law Preview LLC, an educational services company, which he operated for 15 years before selling it to a portfolio company of a private equity firm.