I've noticed a discrepancy between data vendors for Fridays SPY chart. Everyone shows SPX cash having a doji day, closing higher than Thursday's high. Some data vendors show SPY as having a doji day, but closing in the lower half of Thursday's range. I've added a chart which shows stockcharts vs thinkorswim. In SC they show Friday as a doji closing above Thursday's high, in TOS they show Friday as a doji closing well below Thurs close. So far everything else I've seen is the same as TOS, only stockcharts shows SPY matching SPX on Friday.