UK M&A legal market sees resurgence

In the first quarter of 2026, the UK-involved M&A legal landscape exhibited a remarkable transformation. According to data compiled by LSEG a provider of financial markets infrastructure and financial data, this period saw a sharp rise in overall deal value, escalating from $94.3 billion in Q1 2025 to a substantial $133.0 billion this year. Contrastingly, the number of deals took a significant hit, declining from 1,205 to 884. This notable divergence in data highlights a strategic shift towards fewer, larger transactions that are increasingly defining the market.

Slaughter and May took centre stage by capturing the top position among legal advisors, achieving an impressive $42.9 billion in deal value, which equated to a commanding 32.24% market share. The firm accomplished this feat with just five deals, underscoring a growing trend where high-value mandates outweigh total deal volumes. This leap from 10th place in 2025 reaffirms Slaughter and May's resurgence in premium transactions that have proven vital in the current economic climate.

Trailing closely behind were Herbert Smith Freehills Kramer LLP and Linklaters, which ranked second and third, respectively. Both firms showcased significant growth, with their deal values soaring more than fourfold compared to the previous year. Linklaters, in particular, displayed a balanced tactic by combining robust value growth with a relatively higher number of completed deals.

Freshfields and Allen Overy Shearman Sterling LLP completed the top five, maintaining strong standings despite divergent paths. Freshfields, while experiencing a decline from last year's rankings, still delivered solid deal values. In contrast, Allen Overy Shearman exhibited consistent growth in both value and deal count, indicating a strong footing in cross-border transactions that remain vital in today’s market.

The data for 2026 also illuminated a decline for firms that had previously dominated the landscape. White & Case and Latham & Watkins, once in the top four in 2025, encountered substantial drops in both market share and deal value. Meanwhile, Kirkland & Ellis plummeted from the first position in 2025 to 14th in 2026, illustrating a notable reduction in UK-involved activity or a strategic pivot away from the region altogether.

Additionally, mid-tier and international firms made meaningful advancements, with Norton Rose Fulbright breaking into the top 10. De Brauw Blackstone Westbroek and J Sagar Associates also emerged within the upper rankings through fewer but high-value deals. This evolution signifies a growing competitive dynamic where non-traditional players and a globally diversified advisory landscape are increasingly challenging established norms.

A striking trend within the data was the rise of firms securing high rankings with minimal deal counts. For example, Lenz & Staehelin attained a top-15 position with just a single deal, emphasising the outsized influence of mega-transactions in this climate. This indicates a growing polarization of the market, where triumph is increasingly influenced by access to landmark deals rather than sheer volume.

Conversely, several firms faced steep declines or were eliminated from rankings entirely. The likes of Gibson Dunn & Crutcher, CMS, and Travers Smith reported diminishing deal values and market shares, which points to intensified competition and evolving client demands.

In conclusion, the first quarter of 2026 represents a UK M&A legal market that is both recovering and reshaping itself. The increase in total deal value alongside a drop in the overall number of transactions suggests a strategic pivot towards high-impact deals. Elite firms continue to solidify their dominance, while emerging players introduce further competition, paving the way for a more dynamic and value-driven landscape in the future.