DC is owned by Warner, and I believe Warner has kept all its licences in-house, rather than farm them out like Marvel used to do.
Marvel is owned by Disney. It has its own studio, Marvel Studios, that is responsible for all the "Marvel Cinematic Universe" films (Iron Man through to The Avengers). Aside from those, there are some Marvel characters that Marvel does not currently hold the rights to (X-Men = Fox, Spider-Man = Columbia/Sony).
So I don't see how any other studios could jump in with other DC/Marvel characters.