There are a couple of elements; such as new events or the possibility of a negative outcome that can affect a major industry or regions currency that could have a powerful repercussion over the currency's trading rate, regardless the fundamental and technical trading interpretations that are often used to determine the approach to take on the currency market.
What Makes the Market Move?
The variation of the USD is usually considered against the Euro because it is the most popular currencies exchanged pair, so it's the one most used as an example, we took the market indicators that move the market more and update it every year to be considered.
Economic data, although not always of the same kind, has proven to be one of those elements to cause an impact or help predict over the USD movements. With that being said, there are 5 types of the news released on the Forex market that could make the value of the US dollar fluctuate.
1. Non-Farm Payrolls: this is a monthly statistic that shows the total number of US paid workers (except for farms, government, private household and non-profit organization employees). It has recently become more influential over the USD than other indicators.
2. ISM Non-Manufacturing: an index showing the growth or contraction of the non-manufacturing industry.
3. Consumer Spending: also measured monthly, it is the amount of money spent (durables and non-durables) by households in the US.
4. Inflation: the rate at which the price of basic items and services rises, hence the purchasing power of the currency falls.
5. Existing Home Sales: calculated every month, it is the indicator of both, number and prices, of home sales.The Indicators Impact
These indicators do not always keep the same level of impact over the USD. Depending on many different aspects, the order of significance changes every year, but they always manage to be in the top of the lists. For example, a crisis in the housing market could change the categorization of the indicators and impact differently that a U.S. stock market plumb.
Although the impact of the events of the world over the US dollar has progressively lessened, technical and fundamental trading will always be affected by the indicators mentioned before, as they are the ones who make the prices move. Fundamental trading analysis always goes through highs and lows betting on foreign risks. In spite of that, people will most likely consider the risks but fall back on the fundamentals to ensure results, or at least increase chances.