After an onslaught of negative reviews and a dismal opening weekend box office, the future of the Fantastic Four is obviously in doubt. But don't expect to see the characters revert back to Marvel any time soon. Fox's chief of domestic distribution Chris Aronson told THR:
While we're disappointed, we remain committed to these characters and we have a lot to look forward to in our Marvel universe.
By referring to it as "our Marvel universe", you can read between the lines that they have no intention of giving up any of what they have. And they don't necessarily have to. Fox has quite a few options here. They can sit back and wait, letting the memory of the movie fade all the way until 2022 before they have to put another film into production. As long as they do that and release it by 2023, they will continue to retain the rights.
Aronson wouldn't commit to Fox keeping the already scheduled sequel date of June 2017 though.