Following news that Sony will be possibly filming Sinister Six in Vancouver, a Sinister Six teaser image has been found as well.
Sony Brazil posted the following Sinister Six image a couple of weeks ago on Facebook, which reads (translated): "We have plans for you."
Accompanying the image was the following text (translated): "many plans. #Spiderman"
There has been mention of Spider-Man going back to Marvel in Sony leaked e-mails, but most recently Sony and Marvel both shot down the rumor.
With the mention that Sony is looking to film Sinister Six in Vancouver and now Sony Brazil releasing the teaser image with mention of Spider-Man, it seems likely Sony is moving forward with Sinister Six, and possibly also will retain the rights to Spider-Man.
We see on the post that the Brazil fans are well aware of Spider-Man going back to Marvel as the top comment reads (translated): "We want him in Avengers. If this is the plan, I support ... "