Greg Heltzer, recognized by The Legal 500, named a Super Lawyers Rising Star, and rated a Thomson Reuters Stand-Out Lawyer, has extensive experience counseling clients on antitrust matters, with particular focus on transactional antitrust matters and mergers and acquisitions. Greg has successfully defended mergers for ABC Supply, Baxter, Constellation Brands, DaVita, JAB Partners, Mars, Martin Marietta Materials, Motorola Solutions, Olam, TreeHouse Foods, Worthington Industries, and many private equity firms among others.
- Lockheed Martin in multiple acquisitions (aerospace/defense)
- Constellation Brands in multiple transactions including the sale of 30+ brands to E. & J. Gallo, the sale of Svedka, the sale of several brands to The Wine Group, the sale of Nobilo Wine to E. & J. Gallo, and the acquisition of Sea Smoke
- ABC Supply in its acquisition of Feldman Lumber, Rosen Materials, Wallboard Supply, and Coastal Roofing Supply (interiors and roofing)
- Chambers USA, 2026
- The Legal 500 US
- Super Lawyers, Rising Star
- Thomson Reuters, Stand-out Lawyer – independently rated lawyers



- American Bar Association, Antitrust Section
- Georgetown University Law Center, JD, cum laude
- Dartmouth College, AB
- District of Columbia
- Maryland
- US District Court for the District of Columbia

Grégoire Andrieux
Mergers and acquisitions
Leveraged buyouts
Cross-border private equity transactions
Refinancings and divestitures
Debt restructurings
Grégoire Andrieux advises on mergers and acquisitions with a particular emphasis on leveraged buyouts and other complex private equity transactions.
He represents private equity institutions, family shareholders and entrepreneurs in domestic and cross-border acquisitions, refinancings, divestitures, build-ups and debt restructurings.
- Legal 500 EMEA, Leading Individual in France: Private Equity: LBO, 2022-2026
- The Best Lawyers in France, Lawyer of the Year, Private Equity Law, 2026
- Chambers France, Band 1 in Private Equity: Mid-Market, 2026
- The Best Lawyers in France, Private Equity, Corporate Law and Mergers & Acquisitions, Private Equity Law, 2020-2026
- Chambers Europe, Band 2 in France: Private Equity: Mid-market, 2022-2024
- Mergermarket M&A Deals, Highlighted Individual, 2020
Head of the Paris office
- The University of Texas at Austin, LLM
- Paris 1 Panthéon-Sorbonne University, LLM, Business Law, cum laude
- Nantes University, LLM, summa cum laude
- Nantes University, LLB, cum laude
- Paris
- New York
- English
- French

Britt Haxton
Britt Haxton focuses her practice on international corporate tax matters. She advises clients on the new international tax provisions of the Tax Cuts and Jobs Act of 2017 (TCJA). Britt has substantial experience advising multinational corporations on post-acquisition integration strategies and implications of the GILTI regime, FDII, section 245A, and foreign tax credit planning under TCJA. She advises clients on the application of the participation exception under section 245A and the impact on repatriation strategies.
- Structured and managed the post-acquisition integration of 20 subsidiaries in 20 different countries to enable implementation of an integrated workforce
- Provided advice and analysis regarding a multibillion-dollar separation of a multinational corporation into three separate publicly traded companies by means of tax-free stock dividends to shareholders
- Legal 500 US, 2022
- Super Lawyers Rising Stars, 2017 to 2021
- McDermott Lesbian, Gay, Bisexual and Transgender (LGBT) Diversity Committee
- McDermott Associate Recruitment Committee
- McDermott Pro Bono Committee
- Georgetown University Law Center, JD, cum laude
- Creighton University, BS, summa cum laude
- District of Columbia

Debra A. Harrison
As a member of the Corporate Department, Debra focuses her practice on renewable energy transactions, general corporate matters, franchising, licensing and distribution matters, as well as other business growth strategies.
Debra’s corporate practice includes counseling clients, both publicly and privately held, on transactions related to capital formation, mergers and acquisitions, reorganizations, brand extension programs, joint ventures and strategic alliances in a variety of industries. She has extensive experience advising clients on renewable energy transactions, including the structuring, development and financing of renewable projects throughout North America and Europe. Debra has served as counsel for major investment banking clients, large developers, sponsors, utilities, and other lenders and investors in the development, implementation, acquisition, structuring and financing of renewable assets, including the negotiation of acquisition and financing documents (including tax equity and back leverage), strategic investments, PPAs, EPCs, and various agreements related to state and local incentives and renewable energy credits.
- Representing a leading US utility in the acquisition of two large wind energy projects under development and in the negotiation of multiple power purchase agreements relating to utility-scale wind projects
- Representing a leading US utility in the acquisition of a large solar + storage facility under development
- Representing a leading French apparel company in its expansion into the United States
- Best Lawyers in America, Energy Law, 2026-2027
- Legal 500 US, Recommended, 2015, 2017, 2021-2024
- District of Columbia Courts, Capital Pro Bono Honor Roll, 2023
- IFLR1000 Energy & Infrastructure 2015 Guide , Renewable Energy, Latin America
- National Association of Women Business Owners, former counsel
- DC Bar Landlord Tenant Resource Center, firm coordinator
- Children’s Science Center (NOVA), founding member
- George Washington University Law School, JD
- The Ohio State University, BA
- District of Columbia
- Maryland
- Virginia

Travis Harrison
Travis Harrison focuses his practice on counseling individuals and families with regard to their wealth management and estate planning needs. He advises clients on the preparation of wills, trust agreements, powers of attorney, advance healthcare directives and prenuptial agreements. He provides legal counsel in connection with probating estates, analyzing estate and gift taxation matters, advising fiduciaries in connection with the administration and investment of estate and trust assets, and forming partnerships and limited liability companies.
- Best Lawyers in America, Trusts and Estates, 2023-2027
- University of Virginia School of Law, JD
- Brigham Young University, BA, cum laude
- District of Columbia
- Maryland
- Virginia

Kevin Hall
Kevin Hall concentrates his practice on the tax aspects of complex domestic and cross-border transactions and the formation and operation of private equity funds and family offices. Kevin has extensive experience advising buyers, sellers, and joint venture partners on the tax aspects of complex transactions, with a special emphasis on transactions involving healthcare companies. He also regularly represents fund sponsors in structuring funds across a variety of strategies, including buyout, real estate, credit, growth equity and venture capital, co-investment, fund-of-funds, and secondaries.
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- The Best Lawyers in America, Lawyer of the Year in Miami: Tax Law, 2027
- Best Lawyers in America, Tax Law, 2026-2027
- University of Miami School Of Law, adjunct professor
- Florida Law Review, member
- Tax Law Review, Graduate Editor, 2013 – 2014
- New York University, LLM
- University of Florida, JD, summa cum laude
- Wake Forest University, MS
- Wake Forest University, BS
- District of Columbia
- Florida

Steffen Woitz, LL.M.
Steffen Woitz advises German and international clients on intellectual property, antitrust and competition law issues.
He has in-depth litigation experience in all major German courts and assists clients in cross-border disputes and transactions. He represents German and international clients in infringement and other contentious matters relating to trademarks, patents, unfair competition and antitrust law as well as in other commercial law matters. In addition, Steffen is active in the area of cartel damages, having successfully defended clients against cartel damages claims brought by competitors and commercial customers.
Steffen advises clients on cooperation and distribution agreements from a German civil law and an antitrust perspective. He has deep knowledge in the area of competition law compliance. He also advises on a broad range of intellectual property and antitrust issues in connection to national and international mergers & acquisitions.
Steffen advised:
- A leading South Korean manufacturer of solar modules in cross-border arbitration
- The operators of world-leading and well-known health resorts in a trademark, copyright, and unfair trade law dispute.
- A famous Bavarian brewery in trademark infringement litigation
- Handelsblatt/Best Lawyers™, Germany: Litigation, 2027
- Handelsblatt/Best Lawyers™, Germany: Litigation and Intellectual Property Law, 2021-2025
- The Legal 500 EMEA, Recommended, Germany: Patent Law and Dispute Resolution, 2024
- The Legal 500 EMEA, Recommended, Germany: Patent Law, 2021-2023
- The Legal 500 EMEA, Recommended, Germany: Dispute Resolution, 2021
- AmCham Germany NextGen
- Court of Appeal, Berlin, Second State Exam
- Victoria University of Wellington, LL.M.
- Free University of Berlin, First State Exam
- Germany
- German
- English
- French
- Russian

Llewelyn M. Engel
Llewelyn Engel focuses her practice on government investigations, government contracts, lobbying, political contributions, government ethics, and public policy matters. Llewelyn has successfully represented clients in high-profile investigations by the Department of Justice and Congress that entail significant legal, political and reputational risks. Llewelyn is experienced in navigating the political vetting process and has helped a high-profile client nominated by the President undergo the confirmation process.
- District of Columbia Courts, Capital Pro Bono Honor Roll, 2023
- Legal 500 US, Recommended Lawyer: Government Contracts, 2024-2025
- Georgetown University Law Center, JD
- Colgate University, BA, magna cum laude
- Virginia
- District of Columbia
- English

Jonathan Ende
Jonathan (Jon) Ende counsels clients on complex privacy, cybersecurity, and artificial intelligence (AI) questions, helping organizations navigate rapidly evolving regulatory landscapes.
- Assisted numerous companies with global ground-up construction of privacy compliance programs for US state privacy laws in California
- Counseled many companies on cookie litigation and enforcement risk and maximizing value of online data collection technologies
- Supported companies across the automotive ecosystem with complex privacy and data security compliance issues, including connected vehicle services, driver assistance systems, mobile application development, consumer insurance programs, and others
- District of Columbia Courts, Capital Pro Bono Honor Roll, 2023
- University of Virginia School of Law, JD
- University of Virginia, BA, Economics
- District of Columbia
- Virginia
- English
- Japanese

Joshua M. Ellenberg
Joshua (Josh) M. Ellenberg focuses his practice on US and international tax matters.
Josh was previously a judicial intern for the Honorable Shirley M. Watts of the Maryland Court of Special Appeals and for the Honorable Rudolph Contreras of the US District Court for the District of Columbia. While in law school, Josh earned a CALI Award for academic excellence and was recognized for “truly extraordinary academic performance.” He was also a member of the Georgetown Journal of Law & Public Policy.
- Best Lawyers: Ones to Watch in America, Tax Law, 2024-2027
- District of Columbia Courts, Capital Pro Bono Honor Roll, 2023
- Georgetown University Law Center, JD, magna cum laude
- Ner Israel Rabbinical College, MTL
- Ner Israel Rabbinical College, BTL
- Maryland
- District of Columbia
