It's always tough when you hear about the possibility of a sequel to a movie you love. While there is usually that thirst for more, it's rare that a sequel ever matches (let alone exceeds) the original. With a budget around $1 million Insidious has grossed over $69 million globally, so naturally, there are some talks about the possibility of a sequel.
Shock Till You Drop caught up with Insidious producer Jason Blum and asked him if there are any sequel plans. While he says there is nothing official, he does mention that there is a possibility:
"If Leigh comes up with a story that's inventive and you feel like there's a story to tell - as opposed to 'let's make another movie and make money' - and he comes up with something James feels is worth making we would do it. And if Leigh doesn't, we won't."
Without going into story detail spoilers, if they decide to do a sequel, I'd like an all new story with an all new cast as opposed to a direct sequel or prequel. In the meantime, everyone involved with the development of Insidious is currently working on multiple horror projects, so they they have plenty of original material to work on before looking into a sequel.