2025
M&A
Advised a European industrial group on its €18.4bn acquisition of a North American competitor.
Counsel to sovereigns,
institutions and the
boards of public companies.
Ashcroft & Weiss advises on transactions and disputes where the outcome is consequential — for the parties, their markets, and, on occasion, the treasuries of states.
We keep a small partnership by design. What we accept, we complete.
§ 01 — Recent Matters
A selection of work, lightly described.
2025
Sovereign
Counsel to a G20 sovereign on the restructuring of US$46bn external debt.
2025
Capital Markets
Advised the joint bookrunners on the €6.2bn dual-tranche issuance by a supranational.
2024
Arbitration
Represented a Gulf state in a US$4.3bn ICSID claim. Award rendered in favour of the respondent.
2024
Antitrust
Obtained unconditional EU clearance for a Phase II merger in the semiconductor sector.
§ 02 — Practices
Nine practices. One partnership.
§ 01
Mergers & Acquisitions
Board-level counsel on cross-border combinations, carve-outs and public takeovers.
Head
Helena Ashcroft-Marchetti
412
Matters
→
§ 02
Private Equity
Fund formation, acquisitions, and portfolio company matters across Europe, the US and Asia.
Head
Julian Weiss
287
Matters
→
§ 03
Capital Markets
Equity and debt issuances, sovereign and supranational offerings, hybrid instruments.
Head
Sadia Rahimi
196
Matters
→
§ 04
International Arbitration
Investment treaty claims and commercial arbitration before ICSID, ICC, LCIA and SIAC.
Head
Pierre Vaillancourt-Lenoir
148
Matters
→
§ 05
Antitrust & Competition
Merger control, abuse of dominance, cartel defence and EU General Court advocacy.
Head
Dr. Margarethe König
173
Matters
→
§ 06
White Collar & Investigations
Cross-jurisdictional investigations, FCPA, SFO, DOJ and DPA proceedings.
Head
Nathaniel Ogunyemi
94
Matters
→
§ 07
Sovereign & Public International Law
Counsel to states, central banks and international organisations.
Head
Pierre Vaillancourt-Lenoir
61
Matters
→
§ 08
Restructuring & Insolvency
Chapter 11, English schemes, and cross-border restructurings of sovereign and corporate debt.
Head
Iona McBride
82
Matters
→
§ 09
International Tax
Structuring, transfer pricing, and tax controversy across OECD jurisdictions.
Head
Thomas Halvorsen
119
Matters
→
§ 03 — Method
“We are not retained for volume. We are retained when the matter is unusual, the counterparty is formidable, or the timetable is unforgiving — and often when all three are true.”
— Helena Ashcroft-Marchetti, Managing Partner
§ 04 — Offices
Thirteen offices, one file room.
| City | Address | Zone | Since |
|---|---|---|---|
| London† | 14 Lincoln’s Inn Fields | GMT | 1912 |
| New York† | 425 Park Avenue | EST | 1919 |
| Paris | 9 Avenue Matignon | CET | 1926 |
| Frankfurt | Neue Mainzer Straße 52 | CET | 1933 |
| Brussels | Avenue Louise 326 | CET | 1941 |
| Zurich | Bleicherweg 33 | CET | 1948 |
| Geneva | Rue du Rhône 8 | CET | 1955 |
| Singapore | 8 Marina Boulevard | SGT | 1963 |
| Hong Kong | Two IFC, Central | HKT | 1970 |
| Tokyo | Marunouchi Trust Tower | JST | 1977 |
| Dubai | DIFC, Gate Village 4 | GST | 1985 |
| São Paulo | Avenida Brigadeiro Faria Lima | BRT | 1992 |
| Washington | 1050 K Street NW | EST | 1999 |
† Founding seatLast reviewed 01.IV.2026
§ 05 — From the firm
Briefings, memos, and the occasional essay.
Briefing · 24 April 2026
The revised EU Foreign Subsidies Regulation: implications for M&A timetables
Client Memo · 11 April 2026
English scheme of arrangement vs. Part 26A: choosing the right restructuring tool
Briefing · 02 April 2026