Matthew Thomas v. UBS AG

POSNER, Circuit Judge.

The three appellants are the named plaintiffs in a class action suit that seeks damages from UBS, Switzerland’s largest bank, which specializes in managing the assets of wealthy persons from all over the world. Federal jurisdiction is based on the alienage branch of the diversity jurisdiction.

The parties have not made clear the source or sources of the law applicable to the case. The plaintiffs advance a variety of common law claims without indicating the state or nation whose law gives rise to them. They mainly cite law from states in which the three plaintiffs reside…