Here's the comparison between S&P500 and XJO over the last 12...

Here's the comparison between S&P500 and XJO over the last 12 months. The charts are very similar, but went a bit off in mid-February, and the trends have actually gone in opposite directions since the start of May. Even so, when there's a big overnight move we still followed to some extent, as you say. But this is a CFD chart, which definitely follows US overnight.