Mainly the exchange rate of the currencies controlled by the big central banks of the countries and they are the big players in forex and so most of the moves of the market happens by them then the economic crisis or big events has a great effect also on the market and so we find that the market has big volatility and this makes the winning and loses have the same chances and the trader may win or lose any trade, the trader that can read the news well and read for the big traders or analyzers will understand how the market works and how he can expect its next movements and so he will fall in the traps that sometimes made in the market nd will become a good trader and will protect his money and makes profits at the same time