There is no Global Foreign Exchange Rate
There are no official exchanges for trading currencies because they are traded in the over-the-counter market. This explains why there is no official global exchange rate.
The exchange rates that traders often watch in the news and on the Internet come from various sources, but when they decide to open a trade, the exchange rate will most of the time be different. Firstly, all FX brokers set their prices according to the buy and sell orders that they are currently receiving.
Secondly, prices are also dependent upon the flow of quotation received from the liquidity providers on the interbank market. Consequently, different dealers will report different rates slightly. Moreover, an arbitrage plays a vital role in eliminating major discrepancies of the different markets.
How a Forex Broker’s Server Plays a Role
Another important thing that creates a difference in the quotes is the time on broker's server. Sometimes two different brokers can have different times set on their servers and traders can see that difference on 4-hour or daily charts. It is because price charts represent a change in price in a certain time period. So, while at one broker chart traders have the 4-hour candle already closed, at other brokers chart it is still forming. It is same for a daily candle. For example, with one broker the daily candle closes at 00:00 and with others, it can be 23:00.