Former investors in the movie theater chain Regal Entertainment Group on Tuesday filed a petition in the Delaware Court of Chancery seeking appraisal of their shares in connection with the movie theater chain’s $3.6 billion merger with U.K.-based Cineworld Group.

In the filing, hedge fund manager Blue Mountain Credit Alternatives Master Fund and its affiliates asked the court to determine the fair value of more than 6.5 million shares it said it held when the deal closed in late February. The investors had withheld their support from the merger, which created the world’s second-largest theater operator and better positioned the combined company to compete with industry-leader AMC Entertainment Inc.