From 4,889 to 7,710 Lawyers – How US Firms Took Over London
Tom Borman, LawFuel contributing editor
US law firms have turned London into their most important international bridgehead, increasing their lawyer ranks in the City by nearly 60 percent over the past decade and reshaping the U.K. legal market in the process.
The number of lawyers working in London offices of U.S.-headquartered firms rose from 4,889 in 2015 to 7,710 by the end of 2024, a 58 percent increase over ten years.
In total, 84 U.S. firms now have a London presence, underlining the City’s role as the key European hub for U.S. practices.
Standout Market Leaders
Kirkland & Ellis not only hits mind-blowing earnings, but also recorded the largest net increase in London headcount over the decade, adding around 360 lawyers to reach 502 by the end of 2024.
Latham & Watkins now stands as the largest U.S. firm in London by lawyer count, with 535 lawyers in 2024, while Baker McKenzie posted the third-highest 10‑year net increase after previously holding the top spot in 2020.
Goodwin Procter and Paul Weiss, Rifkind, Wharton & Garrison delivered the fastest annualized growth rates over the decade, at approximately 27 percent and 23 percent respectively.
By contrast, firms such as Reed Smith and Jones Day saw their relative London headcount share decline over the same period, underlining how growth has been uneven across the U.S. cohort.
Real estate, office launches and international entrants
U.S. firms have also flexed their muscles in the London office market, taking on average 40 percent more space when signing for new premises between 2014 and Q2 2025, while U.K. firms have taken 23 percent less over the same period.
Between Q1 2021 and Q3 2025, 15 firms opened London offices, 13 of which are headquartered outside the U.S., predominantly from Asia and Continental Europe, highlighting London’s continued appeal as a global legal hub.
Transatlantic mergers and consolidation
Recent high‑profile transatlantic mergers, including combinations such as A&O Shearman and other major U.S.–U.K. tie‑ups, illustrate how firms on both sides of the Atlantic are using consolidation to deepen their reach in each other’s markets.
The data suggests more combinations are likely, with mergers increasingly seen as a defensive strategy for some U.K. firms seeking to maintain market share against aggressive U.S. expansion in London.
Deal work, talent wars and London’s role
U.S.-headquartered firms now dominate the top tiers of the U.K. M&A adviser rankings in the high‑value transactional space for the first half of 2025, reflecting their strong pull with private equity and blue‑chip corporate clients.
These firms continue to engage in assertive lateral hiring and team moves from leading U.K. practices, intensifying competition for key partners, associates and deal mandates in London.
London remains one of the world’s premier transactional centres, offering a diverse client base ranging from global corporates and private equity sponsors to scaling technology and fintech startups.
For U.S. firms, that combination of deal flow, capital and talent has made London the strategic “must‑win” market in their international growth strategy. Nothing looks like it’s going to stand in the way of continued growth in the so-called “London-New York” corridor any time soon. So expect more American firms to eye openings or expansion into the City.
