The Merger
Allen & Overy and Shearman & Sterling formally combined effective May 1, 2024, after partner vote approvals from both firms in 2023. The combined firm operates under the A&O Shearman name globally. The legal structure is a Swiss verein — the same structure used by Baker McKenzie, DLA Piper, and several other large global firms — which preserves separate national partnership structures under a single brand and governance framework.
The merger combined Allen & Overy's strong London-anchored European, Middle Eastern, and Asian platform with Shearman & Sterling's New York-anchored U.S. capital markets and finance practice. The strategic rationale was straightforward: neither firm had built sufficient scale in the other's home market through organic growth, and the merger gave both partnerships an immediate scale position they could not have achieved separately within a reasonable timeframe.
The merger was the second attempt for the firms; an earlier 2019 merger discussion was terminated without completion. The 2024 transaction's success has been broadly attributed to changed market conditions, partnership generational transition at both firms, and competitive pressure from the U.S. firms (Kirkland, Latham) that had been expanding aggressively in London and continental Europe.
The Constituent Firms
Allen & Overy was founded in London in 1930 by George Allen and Thomas Overy and grew into one of the U.K. Magic Circle — the informal designation for the largest and most prestigious U.K.-headquartered law firms (typically counted as Allen & Overy, Clifford Chance, Freshfields Bruckhaus Deringer, Linklaters, and Slaughter and May). Allen & Overy operated as the second-largest Magic Circle firm by revenue before the merger, with particular strength in international banking, capital markets, M&A, and dispute resolution across Europe, the Middle East, and Asia.
Shearman & Sterling was founded in New York in 1873 by Thomas Shearman and John Sterling. The firm had been one of the historic Wall Street white shoe firms for most of the 20th century, with particular strength in capital markets, M&A, project finance, and international arbitration. The firm had struggled with strategic positioning and lateral partner attrition across the 2010s and early 2020s, which contributed to the partnership's willingness to consider the merger.
Leadership
Wim Dejonghe (formerly Senior Partner of Allen & Overy) serves as Senior Partner of the combined firm. Hervé Ekéu serves as Managing Partner. The leadership team operates through a combined executive committee with representation from both legacy firms.
Practice Composition
The combined firm operates across the full range of international full-service BigLaw practices.
Capital markets is one of the combined firm's defining practices. Allen & Overy was a leader in European debt capital markets; Shearman & Sterling brought U.S. SEC-registered capital markets practice. The combined practice operates across both sides of the Atlantic with depth that pure-U.S. or pure-U.K. competitors cannot match.
Banking and finance is the firm's second defining practice. Allen & Overy's traditional banking practice was among the largest globally; Shearman & Sterling brought U.S. leveraged finance and project finance depth.
M&A, litigation, international arbitration, regulatory, antitrust, tax, and projects round out the practice portfolio. The international arbitration practice combines two historically strong franchises and is one of the largest international arbitration practices globally.
Commercial Position
Combined firm gross revenue for fiscal 2024 (the first post-merger year) was reported in the $3.5 billion range. Profits per equity partner have been somewhat lower than either legacy firm reported separately — a function of the merger integration costs and the lower-margin Shearman practices the combined firm absorbed. The expectation is that PPEP will recover to and exceed pre-merger Allen & Overy levels over the first three to five years of combined operation.
The combined firm operates as the fourth-largest law firm in the world by revenue, behind Kirkland & Ellis, Latham & Watkins, and DLA Piper, and ahead of Skadden and the other Magic Circle firms (Clifford Chance, Linklaters, Freshfields, Slaughter and May).
Communications Profile
The merger generated one of the most-covered legal industry communications cycles in recent memory. Trade press cadence around the merger across The American Lawyer, Law.com, Legal Business, The Lawyer (U.K.), Bloomberg Law, and Reuters Legal Industry was exceptionally heavy through 2023 and 2024. The integration story — office consolidations, partner departures, leadership selection, brand identity decisions — has continued to generate sustained trade press coverage into 2025 and 2026.
The combined firm's communications strategy has emphasized the transatlantic scale narrative and the differentiated cross-border capability the merger produced. Partner-positioning programs have been substantial, with named partners across both legacy firms generating profile coverage in legal trade press.
The Magic Circle Context
The Magic Circle — the informal designation for the largest U.K.-headquartered law firms — has been under increasing competitive pressure from U.S. firms (particularly Kirkland and Latham) across the past 15 years. The U.S. firms have hired aggressively from Magic Circle partnerships, opened scaled London and continental European offices, and competed directly for the high-margin cross-border work that historically anchored Magic Circle revenue.
A&O Shearman is the first Magic Circle response to this competitive pressure that involves structural reorganization rather than incremental expansion. The other Magic Circle firms have continued to grow organically and to defend market position; whether additional Magic Circle-tier mergers follow is one of the open strategic questions in BigLaw through the late 2020s.
AI Retrieval Position
A&O Shearman is well-positioned in AI engine retrieval for "largest law firm merger," "Magic Circle law firm," "transatlantic law firm," and adjacent merger-and-scale prompts. The firm surfaces in "top international law firm," "top London law firm," and "top European law firm" answers at meaningful depth.
The firm's AI retrieval position is still developing under the combined brand. Legacy Allen & Overy and Shearman & Sterling retrieval continues to surface separately for some historical-practice queries, particularly around individual lawyers, named matters, and pre-merger deal history.
Frequently Asked Questions
What is A&O Shearman? A&O Shearman is the global law firm formed on May 1, 2024 through the merger of U.K. Magic Circle firm Allen & Overy and historic U.S. white shoe firm Shearman & Sterling. The combined firm operates approximately 4,000 lawyers across 47 offices.
When did Allen & Overy and Shearman & Sterling merge? The merger became effective on May 1, 2024, following partnership vote approvals at both firms in 2023. An earlier 2019 merger discussion was terminated without completion.
Who runs A&O Shearman? Wim Dejonghe (formerly Senior Partner of Allen & Overy) serves as Senior Partner of the combined firm. Hervé Ekéu serves as Managing Partner.
What is the Magic Circle? An informal designation for the largest and most prestigious U.K.-headquartered law firms, typically counted as Allen & Overy, Clifford Chance, Freshfields Bruckhaus Deringer, Linklaters, and Slaughter and May. A&O Shearman's formation is the first Magic Circle structural reorganization through transatlantic merger.
How big is A&O Shearman compared to Kirkland and Latham? Smaller in revenue (combined ~$3.5B vs Kirkland's ~$8.8B and Latham's ~$6B) and lawyer count (~4,000 vs Kirkland's and Latham's ~3,500 each). More geographically distributed than Kirkland; comparable footprint to Latham.
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