Who owns the rights for mamma mia the musical?

The rights for "Mamma Mia!" the musical are owned by Universal Music Group and the producers of the show, including Judy Craymer, who is one of the original creators. The musical is based on the songs of the Swedish pop group ABBA, and the rights to those songs are also managed by Universal Music. The combination of these rights allows for the continued production and licensing of the musical worldwide.