For example, if I am trading a SP500 ETF on the NYSE, the stock exchange opens at 3:30pm CET. Due to the time shift, the stock exchanges in the EU open at 9am CET, meaning I can already gather chart information from SP500 ETFs that are traded here.
Real life example: The SP500 ETF (even though it's the one traded on an EU stock exchange) gains a lot of value again after the corona virus crash. Is it practically possible to use this information to my advantage by immediately buying shares at the NYSE when it opens later? I know that technically the charts aren't connected with each other as each stock exchange trades it's own shares but in reality they are still correlating.
To be fair, due to the duration of an order I think it wouldn't be possible to take advantage of this small marge, but what about big banks with higher volume and high speed trading?