Earlier this year, a rumor surfaced that Legendary Pictures would be making a film about Namor the Sub-Mariner. The rumors suggested that the rights to the character were owned by Universal/Legendary. But, according to Marvel Studios president Kevin Feige, that's not really the case and it's more complicated than that.
When asked by IGN if there was any truth to these rumors, he said no. Feige was then asked if Marvel would make the movie, and this was his reply:
"Yes, but it’s slightly more complicated than that. Let’s put it this way – there are entanglements that make it less easy. There are older contracts that still involve other parties that mean we need to work things out before we move forward on it. As opposed to an Iron Man or any of the Avengers or any of the other Marvel characters where we could just put them in."
It doesn't sound like a Sub-Mariner movie is going to happen anytime soon, but maybe one day it will happen. It sounds like they would if they could right now.