John Nathanson


John is Global Co-Head of Investigations & White Collar and focuses on United States Department of Justice (DOJ) inquiries, Securities and Exchange Commission (SEC), Commodity Futures Trading Commission (CFTC) and other regulatory matters, internal investigations and financial litigation.

John maintains an active trial practice in both criminal and civil financial misconduct cases.

Prior to joining the firm in 2009, John served for five years as an Assistant United States Attorney in the Eastern District of New York, where he was assigned to the Business and Securities Fraud Unit for four years and served as Deputy Chief of the General Crimes Unit. During his time at the U.S. Attorney’s Office, John investigated and prosecuted numerous securities fraud matters, including cases involving CDOs (Bear Stearns asset managers), options backdating, private investment in public equity (“PIPE”), insider trading and other complex accounting and securities frauds.

Before the U.S. Attorney’s Office, from 2001 to 2004, John served as an Assistant District Attorney (ADA) in the Frauds Bureau of the Manhattan District Attorney’s Office. While an ADA, John investigated and prosecuted securities and other business fraud cases, including the successful prosecution of brokerage D.H. Blair & Co., Inc. and several of its executives. Prior to becoming an ADA, John worked as an associate at global law firm primarily on complex securities litigation and investigation matters.


Representative matters

Citigroup in 2022 trial relating to alleged negligent misrepresentations in connection with foreign exchange hedging contracts.

Deutsche Bank in litigation involving its role as arranger of $725 million loan to SunEdison through 2023 eve-of-trial settlement. 

The independent directors of Wells Fargo in connection with internal and DOJ, SEC and other agencies’ multi-year sales practices investigations.

Todd Newman, formerly of Diamondback Capital Management, at trial and on appeal and achieved complete victory when the US Supreme Court declined to rehear the government’s case after the Second Circuit’s landmark decision to overturn Mr. Newman’s conviction for insider trading and subsequent denial of the government’s petition for rehearing.

Christopher Worrall, former employee of the Centers for Medicare and Medicaid Services, in the trial and appeal of charges that he passed confidential rule-making information to hedge fund managers.

CFOs of two public brand management companies in DOJ and SEC investigations relating to alleged improper disclosures relating to accounting for goodwill.

KuCoin Crypto Exchange in a New York Attorney General petition alleging sale of unregistered digital asset securities.

Gemini Trust Company in connection with an investigation and CFTC enforcement action alleging misrepresentations relating to listing of first Bitcoin futures contract and multi-agency investigation of Gemini’s Earn crypto yield product.

A European construction company in a DOJ FCPA matter involving investigations in multiple countries.

Citigroup in investigation of $400 million fraud at Banamex subsidiary, including internal investigation and representation of the company before DOJ, SEC and other regulatory agencies as well as related civil litigation.

A major financial institution in a DOJ’s FIFA anti-corruption investigation.

A major financial institution and individuals in DOJ FIRREA investigations into mortgage lending practices.

Individuals in investigation of insider trading by US-based asset manager in stocks of overseas companies on foreign exchanges.

Galleon Management in all criminal, SEC, fund wind-down and governance matters arising from alleged insider trading at Galleon.

A major building services company in the Manhattan District Attorney’s Office investigation into alleged improper billing.

A major media company in the Manhattan District Attorney’s Office investigation into employee embezzlement.

Two major financial institutions in separate SEC investigations concerning structuring/underwriting CDOs.

A major financial institution in a DOJ and CFTC investigation into certain market practices related to interest rates.

Investment managers in alleged “pay-for-play” criminal and civil investigations related to state pension funds by the Department of Justice, SEC and New York Attorney General.

An investment manager in all criminal and governance matters related to highly-publicized federal bank fraud charges against a major campaign fund-raiser.

A financial institution in an SEC “pay-for-play” investigation of municipal securities dealer.

An individual defendant in DOJ prosecution of bulk cash smuggling charges.

Pro bono

Conduct regular trial advocacy training programs for prosecutors at the International Criminal Court in the Hague, the Netherland.

Represent class of current and former inmates in litigation with Suffolk County New York alleging inhumane conditions in Suffolk County jails.

Represent class of impacted individuals in litigation over New York City’s “stop and frisk” policing methods.

Published Work

  • Nathanson, John, Co-author, (2023) “Witness Interviews in Internal Investigations: The US Perspective”, Global Investigations Review
  • Nathanson, John, Co-author, (2022) “Latest Ripple Development Highlights SEC’s Crypto Approach”, Law360
  • Nathanson, John, Co-author, (2014) “Trends and Strategies in Today’s White Collar Law Cases”, Inside the Minds: Managing White Collar Legal Issues
  • Nathanson, John, Co-author, (2013) “Strange Bedfellows: Insider Trading and Political Intelligence”, Bloomberg BNA


  • Recognized for his work in “Corporate Investigations & White-Collar Criminal Defense” by The Legal 500 United States in 2021 and 2023.
  • Named a “Litigation Star” and “National Practice Area Star” by Benchmark Litigation in 2022.



New York, 1994


United States Supreme Court

United States District Court for the Southern District of New York, 1999

United States District Court for the Eastern District of New York, 1999

United States Court of Appeals for the Second Circuit, 2005


B.A., Williams College, 1989

J.D., University of Pennsylvania Law School, 1993, Journal of International Business Law

A&O Shearman was formed on May 1, 2024 by the combination of Shearman & Sterling LLP and Allen & Overy LLP and their respective affiliates (the legacy firms). Any matters referred to above may include matters undertaken by one or more of the legacy firms rather than A&O Shearman.