Today is the day for equity index futures traders to rollover from the March contract to the June contract . The reason for the change is that as of the opening bell the June contract becomes the front month and therefore the most liquid month.

Given that different charting services and trading platforms use different symbols for the index futures, the easiest way to move to the June contract is to change the Month designator in the symbol from H to M for equity index futures charts and trading platform references.