Last year, rumors circulated that Natalie Portman didn't want to return for the Thor sequel, and Marvel was forcing her to honor her contract and come back for Thor: The Dark World. Whether the rumors were true or not, Natalie Portman appears to be actively promoting Thor: The Dark World for Marvel and is showing no signs of a dispute.
In fact, Natalie Portman even seems happy about the fact that she thinks a Thor 3 is happening. When asked by EOnline about co-star Anthony Hopkins saying he would love to make a Thor 3, Natalie Portman said, "Yeah, well I think they are going to make a Thor 3, so I think Anthony will be pleased."
While the future of the Thor franchise will likely depend a lot on how well Thor: The Dark World does at the box office, it certainly sounds like Marvel Studios is at least planning like it will do well. Could Thor 3 be one of the mystery films already scheduled for release in 2016 and 2017 as part of Marvel Studios Phase 3?