In the latest sign that commercial litigation finance is shaping global litigation, Quinn Emanuel Urquhart & Sullivan said Wednesday that it is readying a novel $25 billion U.K. claim against MasterCard Inc. on behalf of British debit and credit card holders.

The action, which Quinn Emanuel said it expects to file in a specialized competition tribunal in late July or August, will be the largest case by far under a year-old U.K. law that expands the ability of private parties to seek collective redress for violations of U.K. competition law. It also marks the largest investment in a non-U.S. litigation by Gerchen Keller Capital LLC, a Chicago-based commercial litigation financier that has vaulted into the top ranks of third-party funders in size since its founding in 2013. Gerchen Keller has committed up to $55 million to the case.