ES finishes near the low of the trading day of 1271.50 and Russell is pinned to it's high. What a bizarre day.
The Japanese need their money back. This is why assuming correlations will remain intact is very dangerous thinking even if founded on rational principles.
expiration Friday... and a triple witch expiry at that Russell futures have always been erratic and haywire during expiry week... dating back to the ER2 contract. Just because a trading session is open does not mean all are equal to one another. Each trading day is highly unequal to another, many times. TF and expiry days are usually erratic and pinned. Friday was textbook for that. Expect the same thing to repeat most months, and your expectations will be squarely met over time
I have been with RUT for many many years and indeed more than 50% of my trade are related to RUT & IWM Things "change" since last Sep..