I kind of expect all three to match but no such luck. Why are SPY and IVV different? Today, 4/27 SPY: Open: 120.65, Close: 118.48 IVV: Open: 121.04, Close: 118.87 It seems that SPY is a bit lower than IVV for some reason. ^GSPC: Open: 1209.92 Close: 1183.71 which doesn't match even after adjusting by 10. I have an inside bar strategy that works on the index data but not on either of the ETFs. Are the futures they way to go?