An economic or non-economic factor that affects the forex market at any given time. Fundamentals affect the supply of a currency, and likewise the demand for it. There are actually thousands of fundamental factors that could have an impact on the forex market. For example, the performance of a major stock exchange, the oil price, natural catastrophes (droughts, hurricanes, tsunamis, etc), wars and armed conflicts, etc.

Nobody could possibly keep track of all influential factors. Some forex investors may be interested in tracking commodity prices, while others may keep a watchful eye on the stock market. Therefore, what one investor finds pivotal to his strategy might not be important to another investor. In short, a good forex trader need not monitor everything, trivial and substantial, that takes place everywhere around the globe all the time. Instead, it is particularly important to concentrate on the main fundamental factors or the big stuff. The most influential factors could be enlisted as follows:

• Government policies: especially in terms of interest rates and sovereign debt sales to foreigners.
• Inflation: as measured by the consumer price index (CPI).
• Stock market: any major stock exchange such as S&P500 (U.S.), Nikkei (Japan), CAC40 (France), etc.
• Oil price: as measured by crude oil futures.
• Breaking news: as broadcast and published by major news agencies.