Who has clout?

Who? I am not interested in power, I think real power is to be able to give it up. But that is kind of hard to do for most. I personally think that banks are the most powerful because they make demands to distributors-studios. Another question is who in Hollywood has clout, who's yes means anything, who is maping the world? Celebrities and producers may have a lot of clout and make the banks move with the production?