US firms are taking a growing share of London’s biggest court battles

US firms including Quinn Emanuel, Cleary, Reed Smith and Jones Day are increasingly dominating the highest-stakes disputes in London.

New analysis from litigation analytics platform Solomonic found that while US firms accounted for only around 4% of all claims by volume over the past five years, the median claim value for those firms last year was roughly £10 million - around 13 times the all-firm average.

The data points to how aggressively US firms have moved upmarket in London disputes, focusing on large commercial litigation, collective actions and arbitration-related claims rather than volume work.

US firms are also steadily increasing their presence in the Commercial Court, the specialist division handling many of the City’s largest disputes.

According to the analysis, US firms were involved in 15.9% of Commercial Court claims between 2014 and 2019, 15.5% between 2020 and 2022, and 18.9% between 2023 and 2025.

In other words, almost one in five Commercial Court claims now involves a US firm.

The US build

The findings highlight the outcome of US firms investing heavily in London disputes capability in recent years through senior lateral hires, outsized pay packages and the expansion of specialist litigation and arbitration teams.

US firms also appear more willing to push cases to trial. Solomonic found US firms ended up in court in more than 20% of cases, compared with 9% across the wider market.

A small group of US firms stand out for their sustained volume of claims issued in the High Court over the past five years. Quinn Emanuel has been the most active, followed by Cleary and Reed Smith.

The biggest cases

Among the biggest cases before the courts in 2025, White & Case represented Vale, a co-operator of the Mariana dam in the £36 billion claim against BHP. Pogust Goodhead acted for group claimants, while Slaughters acted for BHP later replaced by HSF Kramer following BHP’s High Court loss in November.

The £14 billion Merricks v Mastercard collective action related to consumer overcharges - which ultimately settled for £200 million - involved several leading US firms. Quinn Emanuel originally acted for class representative Walter Merricks before Willkie Farr took over the mandate after partner Boris Bronfentrinker moved firms in 2021 with his team.