US firms are dominating high-value litigation in London despite only handling a relatively small number of claims, according to litigation data from Solomonic.
Median claim value for US firms was around £10m in 2025, compared to £740,000 for other firms – a 13x gap, Solomonic data show. That is despite handling only 4% of claims between 2020 and 2025, and just 2.7% in 2025.
That strategic positioning at the top end of the market is reflected in the number of cases that go to trial. US firms reached a judicial outcome 21% of the time, compared to a market average of 9%.
Solomonic said: “The figures suggest that US firms are disproportionately involved in the most hard-fought, high-stakes disputes. Whether that reflects client profile, litigation strategy, case selection or practice focus, it points to a requirement for... trial case strategy and management capabilities.”
Quinn Emanuel Urquhart & Sullivan leads the top 30 US firms by number of claims issued between 2020 and 2025, followed by Cleary Gottlieb Steen & Hamilton, Reed Smith, Jones Day and Morgan Lewis & Bockius.
The data shows that almost one in five cases in the Commercial Court now involves a US firm, with a notable increase since 2023.
Solomonic said at the top end of the market, value is concentrated in mass group litigation, competition class actions and sovereign or arbitration-related disputes, flagging the £36bn BHP dam proceedings (involving White & Case) and the Merricks v Mastercard case (involving Quinn Emanuel, Willkie Farr & Gallagher, Jones Day and Milbank) as examples.
It added that cases such as Nigeria v P&ID (involving Quinn Emanuel) and Law Debenture v Ukraine (also involving Quinn Emanuel) show how arbitration awards and sovereign debt exposures continue to produce large claims in English courts.
Solomonic said: “US firms are perceived as more aggressive litigators, particularly given their reputation in the US market and their growing involvement in funded disputes, class actions and competition claims.”
Between 2020 and 2025, US firms were involved broadly equally on the claimant (51%) and defendant sides (49%).
A report last month from Lex Machina found that the bulk of US class action cases never reach trial, with about 95% of cases resolved through settlement or procedural outcomes.
Click here to read Solomonic's blog on the US law firm data.
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