The creators of South Park, Trey Parker and Matt Stone, are planning a big-screen version of their hit musical The Book of Mormon after setting up a new $300m production company.

Important Studios, which has been funded by revenue from the popular stage show as well as the long-running South Park TV series, will produce film, TV and theatre projects. Parker and Stone said they were going it alone for creative reasons. "Having worked with several different studios over the years, we came to realise that our favourite people in the world are ourselves," the pair told the New York Times in a statement.

The Book of Mormon currently has New York and Chicago productions running as well as a production touring the US and another about to open in London. The Tony award-winning satire, which centres on two young Mormon missionaries sent to a remote village in northern Uganda, has made more than $200m worldwide so far and continues to pull in almost $5m a week.

Around one fifth of the investment for Important Studios has come from merchant bank the Raine Group, which holds 20% of the company's shares. Stone played down suggestions that the new firm might emerge as a successor to famous independent studios such as Steven Spielberg's DreamWorks or George Lucas's Lucasfilm. "In some ways it's a stupid comparison because they are gargantuan," he said. "We want to be a smaller, more humble version of that."

Stone and Parker, who brought both 1999's South Park: Bigger Longer & Uncut and 2004's Team America: World Police to the big screen, also hope to use the new money to allow them to "be more prolific with less struggle".

"We want to have a little control over our life," Stone explained. "We used to walk into a studio and try to become an employee. We're done with that. We are too grown up for that."

The Book of Mormon opens in London at the Prince of Wales theatre on 25 February.