I actually have two questions here and I'll take a answer for either one of them or both. What's the difference between global and U.S. Exchanges. I.E. why can't people just buy/sell on either? If I have a stock that is already going higher before the US market opens, what kind of sign can I take this as?
The first question on buy/sells off any exchange is due to currency differences. Rates change minute by minute. Some companies on foreign exhanges do trade through the new york exchange by the exchange having a system to convert the currency correctly. Those stocks are listed as ADR. A stock going up in pre-market is a good "indication" it will open up. So you worded your question perfect, it is a "sign" not an assurance.
So the confusion continues as yesterday the stock traded even and I wake up today and it's back up 17% in the other markets.
