The claim of a British private equity investment firm that Citigroup Inc. duped it into making a disastrous bid for the record company EMI Group has been revived.

In a 10-page order issued on May 31, the U.S. Court of Appeals for the Second Circuit vacated a 2010 verdict and ordered a new trial, finding that Southern District Judge Jed Rakoff had incorrectly instructed the jury on relevant U.K. law.