Only one exchange: BITTREX. BITTREX do support the segwit and provides the comfortable situation for the customers and they have also claimed that all of their customers are allowed to hold bitcoin and bcc after first of august
Ok, but will be BCC trade open or just deposit?
BIttrex is proven and tested for a couple of years, if I am going to choose between Poloniex or Bittrex, I would rather choose Bittrex because for now this is the main exchange platform where I am using it since I started here.