Simpson Thacher’s Meteoric Climb (Image Credits: Pexels)
European mergers and acquisitions gained momentum in the opening quarter of 2026, spotlighting the law firms that guided the largest transactions. Simpson Thacher & Bartlett captured the top position among legal advisers by deal value, handling $48.2 billion in deals, a sharp leap from its 21st place the previous year.[1][2] CMS, meanwhile, held firm at the forefront by volume, advising on 37 deals despite a dip from the prior period. These shifts underscore how blockbuster transactions can reshape league table standings overnight.
Simpson Thacher’s Meteoric Climb
A pivotal $33.4 billion deal propelled Simpson Thacher & Bartlett to the pinnacle of the value rankings. The firm advised on the acquisition of AES by a consortium of buyers, marking a standout moment in its European practice.[1] This involvement alone highlighted the firm’s prowess in high-stakes cross-border work.
Overall, Simpson Thacher advised on deals totaling $48.2 billion, outpacing rivals and demonstrating its appeal for megadeals. The rankings, drawn from GlobalData’s Financial Deals Database, reflect the firm’s strategic focus on premium transactions. Such performance also aligned with separate accolades, including Bloomberg’s top ranking for European private equity deals by volume, where Simpson Thacher handled transactions worth $58.8 billion.[2]
CMS Holds Volume Crown Despite Headwinds
CMS defended its position as the most active adviser by number of deals, completing 37 assignments in Q1 2026. The firm had led this category in the first quarter of 2025 as well, cementing its reputation for breadth across the market.[1]
Even as overall deal counts fell year-over-year for CMS, the firm stayed ahead of competitors. This resilience points to deep client relationships and a versatile practice spanning multiple sectors and jurisdictions. White & Case trailed closely with 32 deals, followed by DLA Piper at 30.
Top Performers Across Value and Volume
The league tables revealed a mix of US and UK-based firms dominating both metrics. Kirkland & Ellis secured second place by value with $45.5 billion, while A&O Shearman took third at $37.2 billion.
| Rank | Firm | Value ($bn) |
|---|---|---|
| 1 | Simpson Thacher & Bartlett | 48.2 |
| 2 | Kirkland & Ellis | 45.5 |
| 3 | A&O Shearman | 37.2 |
| 4 | Herbert Smith Freehills Kramer | 21.6 |
| 5 | White & Case | 18.0 |
Volume leaders showed similar concentration, with A&O Shearman and Latham & Watkins rounding out the top five at 27 and 22 deals, respectively.[1]
“CMS was the top adviser by volume in Q1 2025 and retained its leadership in position by this metric in Q1 2026 as well, despite registering a year-on-year (YoY) drop in the number of deals advised. Meanwhile, Simpson Thacher & Bartlett’s ranking by value jumped from the 21st position in Q1 2025 to the top position in 2026. The involvement in $33.4 billion deal for the acquisition of AES by consortium of acquirers played a pivotal role in Simpson Thacher & Bartlett securing the top spot by value in Q1 2026.”
Aurojyoti Bose, Lead Analyst at GlobalData
Implications for the European M&A Landscape
These rankings signal a market favoring firms equipped for large-scale, complex deals amid economic uncertainties. Simpson Thacher’s dual success in M&A value and private equity volume suggests growing investor confidence in private markets. CMS’s volume lead, by contrast, reflects steady demand for mid-market advisory.
Firms like White & Case appeared prominently in both categories, underscoring their balanced approach. The data from GlobalData captures a dynamic period where strategic positioning yielded clear advantages.
As Q2 unfolds, these early leaders set a benchmark for peers chasing similar heights. European dealmakers will watch closely to see if momentum sustains or if new challengers emerge.
