I’m learning about futures now (not trading, but plan to trade one day). I’ve see that the Russell index futures are transitioning from ICE to CME (http://www.reuters.com/article/cme-lse-ice-idUSL1N10E2JZ20150803).
“Derivatives based on the Russell 1000 indexes will be listed on CME in the fourth quarter and will trade on both CME and ICE until July 1, 2017”.