Greg Leonard

Senior Vice President


  • Washington | Europe


Greg Leonard coheads Cornerstone Research’s finance practices. He also heads the firm’s London office. Dr. Leonard has nearly two decades of experience consulting for clients in complex litigation and regulatory proceedings. On behalf of clients, he has led regulatory investigations on both sides of the Atlantic, managing teams and simultaneously supporting experts across multiple related matters. Dr. Leonard has substantial experience directing analyses of large and complex high-frequency financial data sets, from both private entities and trading exchanges.

Dr. Leonard’s expertise includes high-profile matters at the intersection of finance and competition. He has evaluated a range of alleged anticompetitive activities in financial and commodities markets, including collusive conduct by various market participants, at both the class certification and merits stages.

Market manipulation

An expert on market manipulation, Dr. Leonard addresses issues that include allegations of benchmark manipulation, banging the close and other manipulation of settlement indices, misreporting of trade information, front-running client orders, trading to trigger stop-loss orders, spoofing and disruptive trading, wash trading, and inappropriate sharing of proprietary information.

In financial markets, Dr. Leonard has led engagements to evaluate risk management practices and the valuation of complex portfolios of trade positions. He has assessed Last Look features of FX client trading platforms, as well as FX algorithmic trading. In addition, Dr. Leonard has substantial experience in analyzing the execution, fulfilment, and hedging of client orders, from complex, market-moving transactions to smaller, routine orders.

Dr. Leonard’s expertise spans a broad range of financial instruments and physical commodities, both on futures exchanges and in over-the-counter markets. In finance, these include fixed income instruments and interest rate products such as LIBOR and other IBOR-linked instruments, FX, and swaps and swaptions. In commodities, he has led matters involving crude oil, natural gas, natural gas transportation contracts, liquefied natural gas, refined petroleum products, electric power, metals, and agricultural products, among others.

Financial investments and valuation

Dr. Leonard has consulted on issues involving investment activities across various financial instruments, notably auction rate securities, mutual funds, convertible stock, high-yield bonds, and private equity. He has applied real options valuation techniques to assess long-term structured power contracts, and employed other valuation methods to assess aspects of multiyear liquefied natural gas contracts. In addition, Dr. Leonard has conducted valuation analyses of alleged breaches of contract in a variety of contexts.

U.S. natural gas trading research

Dr. Leonard is the former head of Cornerstone Research’s energy and commodities practice. In that capacity, he managed the firm’s research on trading activity and pricing methods in the U.S. natural gas trading markets, based on Form 552 submissions to the Federal Energy Regulatory Commission (FERC).


Order and Trade Data Analysis in Recent Spoofing Investigations


City & Financial Global Market Abuse and Market Manipulation Summit 2024


Expert Forum: Market Abuse 2023—Global Regulatory Priorities and Focus Areas


The Role of Economic Analysis in UK Shareholder Actions


Cross-Market Manipulation Allegations: Economic Implications

Press Release

Liam Colley Joins Cornerstone Research’s London Office


Characteristics of U.S. Natural Gas Transactions: FERC Form 552 Submissions as of July 2021

Press Release

U.S. Natural Gas Physical Trading Volume and Marketed Production Remain High

  • Expert Forum: Market Manipulation and Disruptive Trading Enforcement, Cornerstone Research, 17 January 2019
  • Damages 2018: Recognising Your Options Beyond Discounted Cash Flow, Cornerstone Research, 26 June 2018
  • FERC Technical Conference on Developments in Natural Gas Index Liquidity and Transparency, 29 June 2017
  • “Price Indices, Price Reporting, Price Reporting Agencies (PRAs), and Recent Changes in the Process,” New Risk in Energy 2017, 4 April 2017
  • Antitrust and Regulation in Financial Markets: Navigating New Challenges, Cornerstone Research and the NYU Pollack Center for Law & Business, 19 May 2016
  • “‘Spoofing:’ How to Deal with This Tricky Offense & Its Regulatory Guidelines,” FIA Law & Compliance Division, 14 January 2016
  • “CFTC Enforcement Update,” 2015 Energy and Commodities Conference, 28 October 2015
  • “Spoofing in Commodity Markets: How to Spot the Trading Landmines and Manage the Regulatory Tinderbox,” Roundtable forum at Cadwalader, Wickersham & Taft (London), 24 September 2015
  • “Common Trading Practices: Disruptive or Not?,” Roundtable forum at Cadwalader, Wickersham & Taft (Houston), 13 May 2015
  • “An In-Depth Look at Recent Spoofing Allegations,” Tenth Annual Energy Conference, 10 March 2015
  • “(Not) Breaking Bad: Developing Your FERC and CFTC Compliance Formula,” 2013 Energy & Commodities Conference, Cadwalader, Wickersham & Taft, 10 October 2013